Research Marcel Eens

Abstract

Natal dispersal contributes to the viability of populations in rapidly changing environments. The quick assessment of environmental conditions is beneficial as it reduces individuals' dependency on phenological cues during a narrow settlement phase. Considering the evolutionary dependency of nocturnal species on natural light, skyglow – a pervasive and rapidly expanding form of sensory pollution – emerges as a potential new determinant in the decision-making during natal dispersal. My project is among the first to investigate natal dispersal in nocturnal free-living birds and correlate this with skyglow-mediated nocturnal sky brightness. Using a novel approach, I will track individual differences in pre- and post-migratory movements in response to daily variation in natural and artificial light across a population-level gradient of skyglow exposure. The whereabouts of juveniles will be tracked in a breeding-range-wide network of the species in Belgium, while I combine activity and space use data with detailed measurements and simulations of nocturnal sky brightness. Using the European Nightjar, a visually-orienting insectivore sensitive to subtle changes in ambient light, my project is a unique opportunity to unravel the role of nocturnal light on natal dispersal while playing a pivotal role in a largely unexplored research frontier.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Creemers Jitse

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

How do animals, including humans, and plants cope with stress under altered environmental conditions (e.g., warming, drought), or in the presence of specific contaminants (e.g. PFAS, pesticides) originating from a variety of diverse sources? These are our main running research questions. In this biological/environmental research, it is crucial to trace and quantify different compounds of interest in a broad range of samples ranging from water, soil, and sediments over animal/human- and plant tissues. On the one hand, compounds of interest are hormones, which are well-known signal molecules altered in organisms during stress and being active in a very low concentration range. On the other hand, the ecotoxicological applications require research that keeps pace with the dynamic changes in the new generation of molecules used in industry and the evolution towards raised restriction levels in the environment determined by EU and local governments. Therefore, to claim a worldwide leading position in this field, it is important that we invest in the development of innovative sensitive analytical techniques which allow us to trace and quantify extremely low amounts of different compounds of interest. This project application aims to purchase a sustainable, new generation UPLC-TQD-MS, to improve the analytical platform available. This opportunity will not only support ongoing joint collaborations but will also bring the UAntwerpen to an acknowledged leading position in this field.

Researcher(s)

• Promoter: Prinsen Els
• Co-promoter: Bervoets Lieven
• Co-promoter: Covaci Adrian
• Co-promoter: Eens Marcel
• Co-promoter: Groffen Thimo

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Infectious disease outbreaks can cause massive mortality episodes in both wild and domestic animals. Yet, the mechanisms through which environmental sources of stress underlie such outbreaks remain poorly investigated. Because they are situated high in food webs and aggregate at high densities, seabirds represent excellent study species as they accumulate large amounts of mercury and suffer changes in food availability. In this project, I plan to use an experimental approach to investigate, for the first time, whether mercury exposure, nutritional stress, or their potential combined effect i) promote disease occurrence; ii) disrupt key physiological pathways; and iii) impact on parental care provisioning during the chick-rearing period. I will combine the collection of correlational and experimental data using a population of Magnificent frigatebirds breeding in French Guiana as main model species. This population is exposed to both high mercury levels and to nutritional stress, and it is subjected to massive mortality episodes of chicks likely associated with a herpesvirus infection, offering an unprecedented opportunity to address the above-mentioned research gaps. Never has it been more crucial to understand the potential connection between exposure to environmental stressors and viral disease occurrence in wildlife, as it represents a long-term threat for marine top-predators and biodiversity worldwide, and has been never been investigated experimentally in the wild.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Sebastiano Manrico
• Fellow: Hernández González Miguel

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Astronomical light pollution (skyglow) is a pervasive, broad-scale sensory pollutant which extends far into natural areas. It artificially increases the nocturnal sky brightness and alters natural light cycles which have been relatively constant through evolutionary history. To date, most studies focused on direct light sources affecting nocturnal habitats, while the biological consequences of skyglow on nocturnal communities remain unknown. My project is the first to investigate the impact of skyglow on acoustic and visual communication in free-living birds. I will investigate individual-level communication in response to daily variation in natural and artificial light across a population-level gradient of skyglow pollution (ranging from near-pristine to heavily polluted skies). I will achieve this by using novel, animal-borne tracking technologies combined with highly-detailed measurements and simulations of nocturnal sky brightness. Experimental approaches will also be used. Using the European Nightjar, a nocturnal bird sensitive to subtle changes in ambient light, my project is a unique opportunity to unravel the role of nocturnal light on animal communication while playing a pivotal role in a largely unexplored research frontier.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Evens Ruben
• Fellow: Schnürmacher Richard

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Despite their close phylogenetic relationship and phenotypic similarities, bonobos (Pan paniscus) and chimpanzees (Pan troglodytes), humans closest living relatives, show a distinctive behavioral divergence. Bonobos show a remarkable reduction in aggressiveness, which is hypothesized to co-evolve with a larger suit of correlated traits, the "domestication syndrome". As selection targets gene variants that lower aggression, simultaneous alterations are seen in other behavioral traits. While reactive behaviors (aggression, anxiety) decrease, prosocial behaviors (grooming, play, sex) simultaneously increase. Which genes were targeted remains largely unknown. Here I investigate the role of serotonin as a potential modulator of the behavioral divergence in Pan, a neurotransmitter with a well-documented role in the regulation of both reactive and prosocial behaviors. I will systematically compare aggression, anxiety, grooming, sex and play between the two species and investigate to what extent variation in four largely unstudied serotonergic genes impacts behavioral variation within and between the two species. In addition, I will examine a novel and largely unexplored pathway by expanding our investigation to the hologenome, or the combined set of genomes of the host and its cohabiting gut microbes, the gut microbiome (GM). The GM directly impacts host social behavior through interaction with the gut-brain axis, and plays an important regulatory role in serotonergic signaling.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Staes Nicky

Research team(s)

• Behavioural Ecology & Ecophysiology

Project website

Project type(s)

• Research Project

Abstract

Per- and polyfluoroalkyl substances (PFAS) are chemicals globally present in the environment and biota, as a result of their massive production and use in numerous applications, such as food contact paper, fire-fighting foams, textiles, construction and cleaning products. Their bioaccumulative and persistent properties have led to global regulatory measures for PFOS and PFOA. These are the most frequently detected legacy PFAS and their concentrations are still very high in the environment and biota. In addition, there are many emerging PFAS alternatives developed, with similar structures and chemical properties, not yet regulated and hence used unrestrictedly. However, very little or no information is available on the bioavailability, biomagnification and toxic effects of these emerging compounds, particularly for the terrestrial environment. PFAS may thus accumulate in the environment, posing risks to organisms. There are also many uncertainties on which factors might influence the bioavailability and biomagnification, especially of emerging PFAS. The identification of emerging PFAS, which have largely replaced the legacy PFAS, would allow us to investigate the environmental relevance of currently-used PFAS, as well as to characterize possible point sources. Detailed field studies on soil, plants, invertebrates (e.g. earthworms, woodlice, caterpillars, snails, slugs, and spiders), and great tits (Parus major; a songbird model species) planned in this project will provide us with: 1) an overview of the distribution of legacy and emerging PFAS present in the terrestrial environment near a fluorochemical polluting hotspot in Antwerp, 2) how the concentrations in the food chain are influenced by soil properties, and 3) their potential toxicity in key model species. In addition, experimental lab studies with PFAS and elevated temperature (T) as stressors on terrestrial invertebrates and plants will be performed to: 4) disentangle causal links from confounding effects regarding the soil properties, 5) verify whether or not increased T and PFAS have an additive toxic effect when combined, and 6) create a mechanistic framework explaining the underlying subcellular basis of root growth responses towards PFAS/increased T in the plant model species Arabidopsis thaliana. This project will allow us to understand the bioavailability and mechanism of the toxicity of emerging and legacy PFAS in plants, invertebrates, and birds and will offer instruments for regulators to assess the environmental risk and potential effects on human health.

Researcher(s)

• Promoter: Bervoets Lieven
• Co-promoter: Covaci Adrian
• Co-promoter: Eens Marcel
• Co-promoter: Prinsen Els
• Co-promoter: Vissenberg Kris

Research team(s)

• Ecosphere

Project type(s)

• Research Project

Abstract

Astronomical light pollution (ALP) is one of the most pervasive, rapidly-expanding pollutants causing a broad-scale illumination of the nocturnal sky. It infiltrates far into natural areas and fundamentally changes the natural night-time environment (e.g. lunar cycle) which has been consistent in evolutionary history and tightly controls animals' circadian rhythms. With a near-exclusive focus of research on light pollution caused by direct point sources, we urgently need to understand impact of ALP on nocturnal wildlife. This project is among the first to examine the impact of ALP on the behaviour of free-living nocturnal animals. I aim to investigate i) behavioural differences between natural sites and sites subjected to ALP, ii) behavioural responses across a gradient of ALP, iii) individual responses to daily fluctuations in ALP and iv) individual responses to experimentally-induced ALP. I will achieve this by using state-of-the-art tracking technologies, combined with site-specific light measurements, simulations and manipulations. This allows me to relate variation in daily behaviour (rest, sing, fly, forage) of a nocturnal insectivore, the European Nightjar, to fluctuations in ALP and natural light. Given the sensitivity of the nightjars to subtle changes in ambient light and ten years of experience with the model species in Europe, Africa and Asia, this is an unprecedented opportunity to investigate a research frontier that remains largely unexplored.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Evens Ruben

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Aggressive competition and the signals used during aggressive competition have historically been considered characteristics of male animals produced by sexual selection. Nevertheless, female competitive traits are common across a wide variety of taxa. In most cases, these female traits are understudied. A deeper understanding of how these competitive traits function in female lives is necessary to understand how these traits evolve. Therefore, the overall aim of this project is to study the costs and benefits of female competitive trait expression (female-female aggressiveness, plumage traits/colouration) within a life history and behavioural syndrome framework, answering to recent calls for an integrative and multivariate approach. More concretely, while there is increasing evidence that individual differences in the expression of traits that improve competitive ability ("competitive traits"; e.g. aggression, ornaments) might play a major role in life history trade-offs, this has rarely been examined in females. At the same time, it has become increasingly clear that individuals often consistently differ in a whole suite of behavioural traits, known as personality. This highlights that behavioural traits (like aggression) should not be studied in isolation given they might not be able to evolve independently under selection. Understanding the selective forces acting on competitive traits in females hence requires their integration within both a personality and life history framework, which will be done here for the first time. Using a population of individually-marked free-living blue tits (Cyanistes caeruleus; a songbird species), we will use both observational and experimental approaches to quantify a variety of female behaviours (female-female aggression, exploration, nest defence, maternal care) and ornaments (plumage traits) which are expected to influence reproductive fitness and survival. Solid integration within life history will be done by examining the link with life time fitness variation and telomere dynamics, a potential underlying proximate variable. At the end of this project we aim to have generated a better understanding of the costs and benefits associated with different female competitive phenotypes, and hence why they exist and how they are maintained.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: van Iersel Robin

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Mercury emission into the environment represents a globally relevant issue. The increased methylation rate of mercury due to global warming, and the projections suggesting that the amount of mercury in fish may double by 2050 jeopardize the future of top-predators worldwide. Now more than ever, we need to understand how exposure to mercury contamination affects life history traits of wildlife. I aim to investigate for the first time the consequences of mercury exposure on susceptibility to viral diseases. Specifically, the project aims to assess to which extent mercury exposure: i) causes physiological dysfunction and facilitates the manifestation of the disease; ii) accelerates telomere shortening during the viral disease; and iii) causes parental hormone displacement. The existing high levels of mercury and the annual viral outbreaks that cause the mortality of a large proportion of chicks of Magnificent frigatebirds at the study site (a small island in French Guiana) exploit an unprecedented opportunity to investigate a topic that remains largely unexplored. Not only will I combine the collection of longitudinal (within-individual variation over time) with experimental data, but I will benefit from hundreds of blood samples that I collected previously. The project has an extra value in terms of conservation because it will be carried out on a colony of frigatebirds that is considered one of the most important of South America.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Sebastiano Manrico

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

We will develop a pioneering holistic framework based on innovative approaches to explore the human exposome in terms of exposure leading to adverse effects with a focus on endocrine-modulated neurological and metabolic disorders by: i. Identifying and characterizing the exposure sources of relevant chemicals in the context of the xposome framework; ii. developing and applying in silico, in vitro and in vivo human and animal models to investigate the absorption, distribution, metabolism, and excretion processes after exposure to chemicals; iii. setting up relevant clinical/epidemiological exposure-wide association studies to better understand the associations between exposure and neurological and metabolic disorders in longitudinal and (nested) casecontrol cohorts and including birth cohorts to understand transgenerational mechanisms; iv. using targeted and untargeted omics techniques (e.g. metabolomics and transcriptomics) in human and animal biological systems to aid data-driven discovery of causal factors for adverse health effects; v. linking exposure to mixtures by integrating exposome research with the adverse outcome pathway concept, a novel toxicological framework structuring the cascade of biological events from an initial molecular-level perturbation of a biological system to an adverse health outcome.

Researcher(s)

• Promoter: Covaci Adrian
• Co-promoter: Bervoets Lieven
• Co-promoter: Blust Ronny
• Co-promoter: Eens Marcel
• Co-promoter: Jorens Philippe
• Co-promoter: Knapen Dries
• Co-promoter: van Nuijs Alexander

Research team(s)

• Toxicological Centre

Project type(s)

• Research Project

Abstract

Despite the growing realization that cognition is likely to play an essential role in the adaptation to urban environments, and despite the increased appreciation of profound differences in behaviour among individuals, these aspects have thus far not been aligned. We currently lack a comprehensive, empirically supported and adequate understanding of how individual phenotypes interact with the urban environment, how that is driven by cognition, and what the ensuing consequences for ecological and evolutionary processes are. This requires (i) to gather accurate and repeatable measures on a variety of cognitive traits (e.g. exploration, (social) learning, social and spatial cognition etc…) in a sufficiently large sample size in the wild at the individual level (and in relation to different anthropogenic stressors); and (ii) to investigate the fitness and hence population-level consequences of such intraspecific variation in cognitive abilities.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Müller Wendt

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

This scientific study uses human biomonitoring and environmental measurements to investigate how a group of 300 young people in the region around 3M are exposed to PFAS and what this exposure does in the body. The study design is interdisciplinary.

Researcher(s)

• Promoter: Loots Ilse
• Co-promoter: Bervoets Lieven
• Co-promoter: Eens Marcel
• Co-promoter: Schoeters Greta

Research team(s)

• Centre for Research on Environmental and Social Change

Project type(s)

• Research Project

Abstract

This funding enables the coordination of the different research activities of the Antwerp Primate Ethology & Evolution Lab within the Behavioural Ecology and Ecophysiology research group within the University of Antwerp

Researcher(s)

• Promoter: Eens Marcel

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

It has been known for a relatively long time that the microbes living in our gut play an important role in regulating our physical and mental health. However, recent literature emphasizes the potentially major role of the gut microbiome in the regulation of brain function and behavior. Gut microbes play an important role in the development and regulation of behavior and cognition, giving rise to a connection between the brain and the gut, also known as the gut-brain axis. Conversely, the social behavior of the host itself will directly influence the composition of the gut microbiome, indicating the axis is bidirectional. To date, very little is known about the gut-brain axis in animals, especially in non-human primates. Great apes are of particular interest, since they form an excellent study system to investigate the evolution of the gut-brain axis in humans because of their high evolutionary relatedness. Bonobos in particular form an interesting model-species due to their high overlap in socio-cognitive skills with humans, but surprisingly, their gut microbiome remains largely unstudied. Therefore, the aim of this study is to characterize the bonobo gut microbiome and to investigate which factors drive interindividual variation in gut microbiome composition and diversity, including behavior. Moreover, I will perform behavioral observations combined with experimental microbiome manipulations to closely examine the impact and dependence of the microbiome on bonobo sociality.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Staes Nicky
• Fellow: Torfs Jonas

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Per- and polyfluoralkylated substances or PFAS, which have been used in large quantities since the 1940s because of their applications such as food packaging, are receiving increasing attention since the early 2000s. The production and use of PFAS have led to the global detection in the environment. Despite regulatory measures for perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), the most frequently detected PFAS, there are concerns on many other PFAS that are similar in structure and properties and that are not regulated. Soils form the basis of the terrestrial food chain and PFAS uptake from contaminated soils is known to cause human exposure to PFAS. However, there are many uncertainties on the behaviour of PFAS in soils and the following bioavailability to and bioaccumulation in biota. The general objective of my project is to investigate the role of soil properties and temperature on the uptake and distribution of PFAS in the terrestrial food chain. Descriptive studies, close to a fluorochemical plant, will provide us with an overview of the concentrations of legacy, novel and unknown PFAS in the terrestrial food chain and how these concentrations are influenced by soil properties. In addition, experimental studies will be performed to disentangle causal links from confounding effects, but also to study the uptake and effects in terrestrial invertebrates and plants. This study will help policy makers to set new, or alter existing, PFAS criteria for soil.

Researcher(s)

• Promoter: Bervoets Lieven
• Co-promoter: Eens Marcel
• Co-promoter: Prinsen Els
• Fellow: Groffen Thimo

Research team(s)

• Ecosphere

Project type(s)

• Research Project

Abstract

Perfluoroalkyl acids (PFAAs) are a diverse family of anthropogenic chemicals with unique physicochemical properties that have resulted in numerous industrial and commercial applications. Their broad application and bioaccumulation potential has led to their worldwide presence in the environment and detection in biota including humans. Over the last decade, consuming food products by humans from self-cultivation has become a remarkable trend in rural, urban and even industrial areas. Nevertheless, PFAAs can enter the food chain due to their widespread use and food intake has been identified as a major pathway for human exposure to PFAAs. Despite the ubiquitous presence and known bio accumulation potential of PFAAs, there is no overview of their spatial distribution pattern or degree of exposure via dietary intake. Nevertheless, it is crucial to solve these two major knowledge gaps to reveal the health risks associated with PFAA exposure. Therefore, the objectives of this proposal are (I) investigate the accumulation of PFAAs in important food items (chicken eggs and vegetables) from private gardens and the influence of soil characteristics, (II) develop a biomonitoring tool that estimates the risks associated with PFAA contamination in food, (III) deliver novel insights in the toxic properties and effects of PFAAs in chickens and (IV) investigate if PFAA concentrations in the food items exceed safety threshold values for human consumption.

Researcher(s)

• Promoter: Bervoets Lieven
• Co-promoter: Eens Marcel
• Fellow: Lasters Robin

Research team(s)

• Ecosphere

Project type(s)

• Research Project

Abstract

Similar to humans, emotions in animals affect their daily lives in many ways. While human studies rely on verbal reports for measuring subjective emotions, we need to apply a different approach for measuring animal emotions. The intensity of emotions has long been studied using behavioural and physiological measures, but these measures fail to identify the emotional valence. Positive emotions appear especially challenging to identify. Recent findings suggest that emotions also affect cognitive processes like attention, judgement and memory and that biases in these performances may give insight in the valence of experienced emotions. This project focuses on studying emotions in man's closest living relative: the bonobo. The bonobo is considered the most suitable model for reconstructing our last common ancestor and hence is a keystone species in studying our evolution and identifying unique human traits. Bonobos have rich emotional lives and respond to the emotions of others in strikingly similar ways as humans. However, the degree to which emotions of bonobos affect their own behaviour, physiology and cognition is currently unknown. To this extent, this project aims to apply a multi-componential approach to study emotions, specifically positive ones, in the bonobo using behavioural, physiological and cognitive measures. Results will be integrated to better understand emotions in bonobos and how positive emotions affect their daily lives.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Stevens Jeroen
• Fellow: Laméris Daan

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Individual differences in the expression of traits that improve competitive ability ("competitive traits"; e.g. aggression, ornaments) might play a major role in life history trade-offs, but this is rarely examined in females. At the same time, it has become increasingly clear that individuals often consistently differ in a whole suite of behavioural traits, known as personality. This highlights that behavioural traits (like aggression) should not be studied in isolation given they might not be able to evolve independently under selection. Understanding the selective forces acting on competitive traits in females hence requires their integration within both a personality and life history framework, which will be done here for the first time. Using the great tit (a songbird species) as a model, I will examine whether females consistently differ in a wide variety of ecologically relevant behaviours (female-female aggression, nest defence, exploration) and whether this is associated with differences in melanin-based plumage traits and investment in parental care. Solid integration within life history will be done by examining the link with life time fitness variation and telomere dynamics, a potential underlying proximate variable. At the end of this project I aim to have generated a better understanding of the costs and benefits associated with different female competitive phenotypes, and hence why they exist and how they are maintained.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Pinxten Annie
• Fellow: Thys Bert

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Perfluoroalkyl acids (PFAAs) are a diverse family of anthropogenic chemicals with unique physicochemical properties that have resulted in numerous industrial and commercial applications. Their broad application and bioaccumulation potential has led to their worldwide presence in the environment and detection in biota including humans. Over the last decade, humans consuming food products from self-cultivation and local companies has become a remarkable trend in rural, urban and even industrial areas. Nevertheless, PFAAs can enter the food chain due to their widespread use and food intake has been identified as a major pathway for human exposure to PFAAs. Despite the ubiquitous presence and known toxic effects of PFAAs, there is no overview of their spatial distribution pattern or degree of exposure via dietary intake. Nevertheless, it is crucial to solve these two major knowledge gaps to reveal the health risks associated with PFAA exposure. Therefore, I will (i) develop a biomonitoring tool that estimates the risks associated with PFAA contamination in food, (ii) clarify the spatial distribution pattern of PFAAs and (iii) deliver novel insights in the toxic properties and effects of PFAAs. My research outcome will significantly improve the monitoring capabilities of regulatory agencies while the outcome of the studied PFAA effects will be of great relevance for the poultry industry, especially companies located within proximity of PFAA producing and processing industry.

Researcher(s)

• Promoter: Bervoets Lieven
• Co-promoter: Eens Marcel
• Fellow: Lasters Robin

Research team(s)

Project type(s)

• Research Project

Abstract

The difference in cognition between humans and apes is not simply a greater degree of general intelligence, but rather a quantitative difference in social cognition. Social cognition comprises the ability to understand and respond to social responses of others. This concept includes social skills related to self-knowledge and theory of mind, which indicates the ability to understand the emotions and behavior of a person from their perspective. This project focuses on our closest living evolutionary relatives: bonobos and chimpanzees. These two species diverged from the human lineage only 5-8 mya. This makes them keystone species for investigating our own evolutionary past and identifying unique human traits. Bonobos and chimpanzees diverged from each other between 1-2 mya, but show considerable differences in social cognition. Studies in bonobos have shown that they have higher social sensitivity and are better at tasks that require social tolerance and cooperation. To date, very little is known about the mechanisms behind these behavioral differences. Therefore, this study aims to contribute to our understanding of the evolutionary origins of human sociality by studying the genetic mechanism underlying these differences in these two closely related ape species. More specifically, I aim to investigate variation in candidate genes that play an important role in the regulation of the social brain, and how they impact sociability, cooperation and social tolerance.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Stevens Jeroen
• Fellow: Staes Nicky

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Artificial light at night (ALAN) or light pollution is an increasing and worldwide problem. There is growing concern that because of the disruption of natural light cycles, ALAN may pose serious risks for wildlife. While laboratory studies have shown that ALAN affects many aspects of animal behaviour and physiology, few studies have experimentally tested how free-living animals respond to ALAN. Furthermore, new lighting strategies are being used as these are considered to be ecologically friendly. However, the effects of ALAN are largely unexplored and even less is known about mitigating strategies. I will for the first time experimentally study, in an integrated way, the effects of long term exposure to ALAN in adult and developing free-living great tits, an important model species. Furthermore I will quantify the effectiveness of part-night lighting (e.g. lights off from midnight till 05:00) and low light intensities as potential mitigating strategies. In adults, I will study to what extent ALAN compromises the immune system. I will also examine the disruption of sleep by ALAN, and how this may affect food provisioning. Finally, I will study the effects of ALAN on early development and physiology of nestlings. At the end of this project, I aim to have a better understanding of the behavioural and physiological consequences of ALAN exposure in adult and developing animals and the effectiveness of emerging mitigating strategies.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Raap Thomas

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

key driver of land-use changes in tropical areas is commercial logging. Recent assessments of biodiversity have shown that there is a decrease of biodiversity in logged tropical forests, but also that there is large variation in how species are affected, indicating that some species are more vulnerable to logging than others. An important question then is which traits affect the species' capability to persist in degraded habitats. The answer to this might lie with the physiological mechanisms governing an organism's response to stressful stimuli. In this project, I will assess for the first time whether the capability to physiologically cope with stress is a mechanism driving the adaptive response of birds to the novel environmental conditions created by selective logging. To this end, I will carry out experimental investigations and comparative studies on birds in both unlogged (i.e., primary) and logged tropical forests of Borneo, a biodiversity hotspot severely impacted by selective logging. The complementary expertises of the (co-)promoters and the foreign collaborator and an established tropical field system with plots of both unlogged and logged forest guarantee the feasibility of my proposal.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Messina Simone

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Sleep is an adaptive state of inactivity, which plays critical functions including replenishing energy and neurological recovery. Artificial light at night (ALAN) is ubiquitous in the urbanizing world, and has the potential to substantially alter sleep patterns. Our understanding of how ALAN affects sleep in wild animals is seriously limited, because past studies have relied on behavioural metrics of sleep, which cannot distinguish different types of sleep (rapid eye movement (REM) versus slow wave sleep (SWS)), or accurately quantify sleep intensity (amount of slow waves within SWS). In this study (CitySleep), the Experienced Researcher (ER) will use state-of-the-art neurologgers to obtain electroencephalogram (EEG) data on sleep in wild great tits (Parus major) exposed to ALAN. She will obtain data from free-living nestlings and from adults in semi-natural aviaries. Great tits sleep in nest boxes that can be experimentally exposed to ALAN, and have served as a model species in behavioural sleep studies. The ER will work with the University of Antwerp's Behavioural Ecology and Ecophysiology (BECO) Group, which has developed methods to manipulate ALAN inside boxes, and has high-quality publications on how ALAN affects sleep behaviour. She will receive expert training on implanting neurologgers from Prof. A. Vyssotski (University of Zurich), and training on interpreting EEG data from Dr. N. Rattenborg's Avian Sleep Research Group (Max Planck Institute). She will contribute expert knowledge of urban ecology, stress physiology and bird handling, and introduce neurologgers to the BECO Group, facilitating a major advance in research methodology. Results will be disseminated through top-tier publications, international conferences and public engagement, and used to advance scientific knowledge and motivate environmental policy changes. The ER will gain skills that will propel her research to a higher level and allow her to secure a permanent research position.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Grunst Melissa

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Culture is a central theme in understanding variation between human societies and a hallmark of the human species. In recent years, culture has been identified in non-human animals as well. These accounts, however, merely evidence cultural traditions (i.e. delineated behaviours like cracking nuts with wooden instead of stone tools), while human cultures also differ from one another in terms of group-level sociality, i.e. the very proclivity to be near and interact with others. Importantly, in humans, it is not any cultural tradition, but this group-level sociality (henceforth "social culture") that results in marked variation in the expression of adaptive behaviour, e.g. cooperation. My project investigates whether differences in sociality across great ape populations can be understood in terms of "social culture" (e.g. by focusing on genetics), and whether these differences explain variation in cooperation. I will study both sanctuary- and zoo-housed populations of bonobos and chimpanzees. I will test the hypotheses that great ape groups differ in their sociality, that this variation can be ascribed to "culture", and that social groups are better poised to cooperate. Chimpanzees and bonobos are our closest living relatives, having diverged from the human lineage only 5–8 mya. As such, both species form a unique window into our evolutionary past, i.e. into gaining an understanding of the behavioural phenotype of our last common ancestor and identifying uniquely human traits.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Stevens Jeroen
• Fellow: van Leeuwen Edwin

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Perfluoroalkyl acids (PFAAs) are substances which have been produced for more than five decades. Their unique properties of repelling both water and oil, make them suitable for many industrial and consumer applications such as water and dirt repellents for cloths and carpets, active components in firefighting foams or precursors in Teflon® production. Its extended use, together with their high persistence, resulted in a global contamination of the environment, wildlife and even humans. This ubiquity contrasts sharply with the limited information about their effects on organisms. With this study I will contribute to finding answers to fill some of the most important knowledge gaps in the toxicity mechanisms of these compounds. For this purpose, I will use two model bird species: great tits (Parus major) and canaries (Serinus canaria). Firstly, I will study the PFAAs exposure levels and the fitness consequences in free-living great tits along a PFAAs gradient from a fluorichemical plant in Antwerp, Belgium. Secondly, I will reproduce the exposure levels in captive canaries in order to replicate the results, found in the field, in a more controlled environment. The studied biomarkers will cover several levels of biological organization, from molecular to individual responses. As a result of my study, the PFAAs toxicity mechanisms will be better understood and their impact at an individual and population level can be more accurately forecasted.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Bervoets Lieven
• Fellow: Lopez Antia Ana

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Individual differences in the expression of traits that improve competitive ability ("competitive traits"; e.g. aggression, ornaments) might play a major role in life history trade-offs, but this is rarely examined in females. At the same time, it has become increasingly clear that individuals often consistently differ in a whole suite of behavioural traits, known as personality. This highlights that behavioural traits (like aggression) should not be studied in isolation given they might not be able to evolve independently under selection. Understanding the selective forces acting on competitive traits in females hence requires their integration within both a personality and life history framework, which will be done here for the first time. Using the great tit (a songbird species) as a model, I will examine whether females consistently differ in a wide variety of ecologically relevant behaviours (female-female aggression, nest defence, exploration) and whether this is associated with differences in melanin-based plumage traits and investment in parental care. Solid integration within life history will be done by examining the link with life time fitness variation and telomere dynamics, a potential underlying proximate variable. At the end of this project I aim to have generated a better understanding of the costs and benefits associated with different female competitive phenotypes, and hence why they exist and how they are maintained.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Pinxten Annie
• Fellow: Thys Bert

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Ecosystems around the globe are heavily affected by anthropogenic influences, threatening especially long-lived organisms like seabirds. Besides climate-change-induced shifts in the marine food web, many seabirds get killed as bycatch in fisheries, but fishery discards are also valuable food. Previous research has shown that even in dietary generalists individual birds can be specialised on food sources. This can be linked to personality (e.g. whether birds are bold or shy), age or sex, potentially making fishing vessels more attractive for some individuals than others. In this proposal, I aim to 1) explore among-individual differences in foraging behaviour, diet and interactions with fishing vessels in northern fulmars (NF; Fulmarus glacialis), and whether these are related to the birds' personality, age and sex as well as offspring growth, physiology and survival, thereby comparing NF from the North and South of Iceland as these populations experience different oceanographic conditions and population trends; 2) as an additional step compare the foraging behaviour of Icelandic NF with that of their southern counterparts, making use of existing data from southern fulmars (F. glacialoides), which breed at a similar latitude as Iceland, yet experience different ecological conditions (lower temperatures, sea ice, no fisheries). This project will deliver fundamental information about individual specialisation in long-lived seabirds and is highly relevant for species conservation.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Dehnhard Nina

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Artificial light at night (ALAN) has been underexplored as an anthropogenic stressor compared to chemical and noise pollution and it can be considered a threat to biodiversity. Because organisms have evolved with the periodicity of light dark cycles, ALAN may affect multiple aspects of behaviour and physiology. Changes in behaviour and physiology associated with ALAN may have particularly strong effects early in life, when developmental trajectories are sensitive to stressful conditions. Yet, a major gap in knowledge involves the effects of ALAN during development, particularly in natural populations. Using birds as a model, we will perform the first study to comprehensively examine how exposure to ALAN affects physiological stress in nestlings in the short- and long-term. We will examine whether early life light exposure affects aging rate, as indicated by telomere dynamics. Finally, we will assess whether exposure to ALAN early in life has enduring effects on the phenotype and fitness (reproduction, survival) of adults. We will use experimental approaches, involving manipulations of light inside nestboxes and cross-fostering experiments. We will also collect correlational data, using a population exposed to heterogeneous light regimes. By elucidating effects of ALAN on developing organisms and assessing mitigating strategies (such as part-night lighting), our study will motivate action to cope with the consequences of living in lighted environments.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Pinxten Annie

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Toxic pollutants increasingly threaten the integrity of natural populations. Metal pollution can have particularly detrimental effects on organisms and entire ecosystems. One potent means by which metal pollution may affect organisms is by elevating oxidative stress, resulting in biomolecular damage and fitness declines. However, the long-term behavioral and fitness implications of metal-induced oxidative stress are poorly understood. Using great tits (Parus major) as a model species, I propose to comprehensively explore how metal pollution affects oxidative stress, aging rate, behavior and fitness. I will perform the first study to examine whether metal-induced oxidative stress affects aging rate, on the molecular level as indicated by telomere degradation, and in terms of sexual signals and fitness traits. I will also explore effects of metal pollution on risk-taking behavior, which may be altered via effects of oxidative stress on neural function and life history decisions. I will study nest box populations of great-tits located across a metal pollution gradient. Experimental approaches will include exposing nestlings to metals and antioxidants, a parental risk-taking experiment, and measuring exploratory behavior in the laboratory. This study will make a pioneering contribution to evolutionary biology by testing the oxidative stress theory of aging in the context of metal pollution, and have critical importance to ecotoxicology and conservation biology.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Pinxten Annie
• Fellow: Grunst Andrea

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

In this project, I therefore plan to investigate for the first time the relationships among environmental changes, stress hormones (corticosterone), oxidative stress, immune cell counts and herpes virus infections, using nestling Magnificent frigatebirds living on the Ile du Grand Connétable as my model system.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Costantini David
• Fellow: Sebastiano Manrico

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Light pollution is likely to have a diverse and complex impact on individual animals. It can influence multiple biological systems simultaneously both directly and indirectly. The overall aim of this project is therefore to study the effects of light pollution and emerging mitigating strategies (part-night and adaptive lighting) on songbirds (great tits) in an integrated way.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Pinxten Annie
• Fellow: Raap Thomas

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

A key driver of land-use changes in tropical areas is commercial logging. Recent assessments of biodiversity have shown that there is a decrease of biodiversity in logged tropical forests, but also that there is large variation in how species are affected, indicating that some species are more vulnerable to logging than others. An important question then is which traits affect the species' capability to persist in degraded habitats. The answer to this might lie with the physiological mechanisms governing an organism's response to stressful stimuli. In this project, I will assess for the first time whether the capability to physiologically cope with stress is a mechanism driving the adaptive response of birds to the novel environmental conditions created by selective logging. To this end, I will carry out experimental investigations and comparative studies on birds in both unlogged (i.e., primary) and logged tropical forests of Borneo, a biodiversity hotspot severely impacted by selective logging. The complementary expertises of the (co-)promoters and the foreign collaborator and an established tropical field system with plots of both unlogged and logged forest guarantee the feasibility of my proposal.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Costantini David
• Fellow: Messina Simone

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Perfluoroalkyl acids (PFAAs) are substances which have been produced for more than five decades. Their unique properties of repelling both water and oil, make them suitable for many industrial and consumer applications such as water and dirt repellents for cloths and carpets, active components in firefighting foams or precursors in Teflon® production. Its extended use, together with their high persistence, resulted in a global contamination of the environment, wildlife and even humans. This ubiquity contrasts sharply with the limited information about their effects on organisms. With this study I will contribute to finding answers to fill some of the most important knowledge gaps in the toxicity mechanisms of these compounds. For this purpose, I will use two model bird species; great tits (Parus major) and canaries (Serinus canaria). Firstly, I will study the PFAAs exposure levels and the fitness consequences in free-living great tits along a PFAAs gradient from a fluorichemical plant in Antwerp, Belgium. Secondly, I will reproduce the exposure levels in captive canaries in order to replicate the results, found in the field, in a more controlled environment. The studied biomarkers will cover several levels of biological organization; from cellular to population response. As a result of the study, the PFAAs toxicity mechanisms will be better understood and their impact at an individual and population level can be more accurately forecast.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Bervoets Lieven
• Fellow: Lopez Antia Ana

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

A major challenge for ecologists and evolutionary biologists is in understanding how organisms will face the ongoing environmental changes. A hitherto unconsidered route whereby organisms adjust their phenotype to their environment is through early life priming to stressful conditions. Although the importance of early life priming in ageing research is increasingly advocated, we lack experimental studies that test whether early life priming of stress responses improves resilience to later life stress exposure and whether this results in organisms better able to reproduce. In this project, I propose to examine experimentally for the first time whether early life priming to oxidative stress increases the capacity of individuals to withstand oxidative stress later in life, whether this early life priming increases lifetime reproductive success and whether this early life priming offsets any detrimental effects of maternal age on the offspring. This innovative project that integrates state of the art developments in ecology and physiology will be of key importance to develop models and to set new standard metrics to assess and predict the responses of natural animal populations to a changing world.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Costantini David

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Families in which two parents raise their offspring are currently no longer seen as a harmonious unit. They rather represent a battleground shaped by evolutionary conflicts of interest among its members that are not perfectly related. This is particularly true for parents. Although parents temporarily cooperate to enhance offspring survival, each parent can gain extra benefits by transferring the largest workload to the partner. Parents thus need to negotiate about their investment to reach optimal cooperation. However, it is currently unclear how such negotiation can contribute to evolutionary stable levels of care. This is largely due to a lack of empirical knowledge about (1) how the negotiation process develops throughout a reproductive event, (2) sex differences in the costs and benefits of negotiation and (3) potential physiological constraints on cooperation. The aim of this proposal is to fill and bridge these knowledge gaps via carefully designed experimental manipulations of parental exploitation opportunities, sexual conflict intensity and family structures. Meanwhile, I will include a proximate view to examine the extent to which hormone profiles constrain negotiated levels of care. Taken together, this proposed research will significantly increase our knowledge about the mechanisms that lead to conflict resolution and set the stage for the next generation of theoretical negotiation models explaining evolutionary stability of biparental care.

Researcher(s)

• Promoter: Müller Wendt
• Co-promoter: Eens Marcel
• Fellow: Iserbyt Arne

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

The aim of this project is to study condition-dependence of song and mate choice in canaries (Serinus canaria). So far, experimental studies have focussed on the effect of environmental quality in order to study condition dependence, in particular in the context of the 'developmental stress hypothesis'. The main focus of this study will be on (a) the effect of genetic condition on the expression of song and (b) the consequences of genetic quality for female mate choice.

Researcher(s)

• Promoter: Müller Wendt
• Co-promoter: Eens Marcel
• Fellow: De Boer Raïssa

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

This project represents a research contract awarded by the University of Antwerp. The supervisor provides the Antwerp University research mentioned in the title of the project under the conditions stipulated by the university.

Researcher(s)

• Promoter: Blust Ronny
• Co-promoter: Bervoets Lieven
• Co-promoter: Covaci Adrian
• Co-promoter: Eens Marcel

Research team(s)

Project type(s)

• Research Project

Abstract

A group of environmental chemicals that has received increasing attention the last two decades are the Perfluoralkyl Substances or PFAAs. Since the 1950s, PFAAs have been used in high quantities because of their excellent surfactant behaviour in applications such as carpet coatings and food packaging. Their broad application and bioaccumulation potential has led to their worldwide detection in biota. Few studies, however, have investigated the effects of PFAAs on terrestrial wild organisms at environmentally realistic concentrations. The general objective of this proposal is to investigate the accumulation and effects of the most prevalent PFAAs in terrestrial organisms, including soil invertebrates and songbirds. Sampling sites will be established along a pollution gradient in the neighbourhood of a fluorochemical plant. Levels of PFAAs will be measured in soil, rain water, soil invertebrates and in songbirds. Besides accumulation, effects will also be assessed on the biota in an integrated way. We will look at physiological, reproductive and behavioural responses. This will be combined with laboratory experiments enabling us to disentangle causal links from confounding effects between PFAAs exposure and effects. In the laboratory invertebrates and songbirds will be exposed to a selection of PFAAs based on the results of the field study. The same endpoints as in the field will be assessed. This study will help policy makers to set environmental quality standards (EQS).

Researcher(s)

• Promoter: Bervoets Lieven
• Co-promoter: Eens Marcel

Research team(s)

Project type(s)

• Research Project

Abstract

Light at night (LAN) is likely to have diverse and complex impacts on individual animals. It can influence multiple biological systems simultaneously both directly and indirectly. Therefore the overall aim of this project is to study the effects of LAN on songbirds in an integrated way. Great tits (Parus major) are highly suited to address our objectives.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Pinxten Annie

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

The aim of the proposed project is to study the space use strategies, foraging behaviour and diet of an assembly of four petrels during the breeding season in two regions within Eastern Antarctica. A major focus will be on the identification of habitat requirements within the two distinct regions and the effects of wind speed and wind direction on the space use decisions and flight costs of the different species.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Dehnhard Nina

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

In this project, I therefore plan to investigate for the first time the relationships among environmental changes, stress hormones (corticosterone), oxidative stress, immune cell counts and herpes virus infections, using nestling Magnificent frigatebirds living on the Ile du Grand Connétable as my model system.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Costantini David
• Fellow: Sebastiano Manrico

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Light pollution is likely to have a diverse and complex impact on individual animals. It can influence multiple biological systems simultaneously both directly and indirectly. The overall aim of this project is therefore to study the effects of light pollution and emerging mitigating strategies (part-night and adaptive lighting) on songbirds (great tits) in an integrated way.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Pinxten Annie
• Fellow: Raap Thomas

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

In this project, I propose to address the following hypotheses using the canary (Serinus canaria) and the great tit (Parus major) as model species: prereproductive oxidative stress reduces subsequent reproductive investment; high parental effort in chick-rearing increases parental oxidative stress and reduces survival or future investment in reproduction; oxidative stress experienced during incubation reduces subsequent investment in chick-rearing. To this end, I will use a combination of experiments that will manipulate the pre- or post-laying oxidative stress level or the oxidative stress induced by chick-rearing effort.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Costantini David

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

The central aim of my research project is to study how females may shape the phenotype of their offspring via the deposition of MAb into eggs, and how this maternal deposition is affected by their own body, physiological and immunological conditions (later referred to as female phenotypic quality). I will first examine the transfer of MAb from the mother to the eggs. Second, I will look at the effects of these MAb on the physiology, humoral immunity, growth and survival of the embryos and chicks. Finally, I will also examine the potential role of corticosterone, the main avian stress hormone, on these mechanisms. To this end, a combination of correlative and experimental approaches will be used.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Poisbleau Maud

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Interactions between caring parents and their offspring are one of the most widespread social behaviours in animals. These parent-offspring interactions involve two parties and its evolution is, therefore, dependent on the evolution of two traits, parental provisioning and offspring begging. From a quantitative genetic perspective both behaviours should co-adapt, which should ultimately lead to (genetic) co-variation. But evidence for co-adaptation, its underlying genetics and the potential fitness consequences is as yet very limited, especially in natural populations. To test predictions of the co-adaptation hypothesis I make use of wild blue tits (Cyanistes caeruleus)

Researcher(s)

• Promoter: Müller Wendt
• Co-promoter: Eens Marcel
• Fellow: Lucass Carsten

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

The aim of this project is to study condition-dependence of song and mate choice in canaries (Serinus canaria). So far, experimental studies have focussed on the effect of environmental quality in order to study condition dependence, in particular in the context of the 'developmental stress hypothesis'. The main focus of this study will be on (a) the effect of genetic condition on the expression of song and (b) the consequences of genetic quality for female mate choice.

Researcher(s)

• Promoter: Müller Wendt
• Co-promoter: Eens Marcel
• Fellow: De Boer Raïssa

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

The aim of this study is to investigate how environmental variability (measured as SST) across several years affects the condition of the same individual females and their timing of egg laying as well as their reproductive investment. I expect to find such effects as SST should affect the prey availability in general (through the availability of nutrients) and the timing of the peak in prey availability in special. As SST are expected to increase in the course of climate change, my study could help to understand the effects and identify successful strategies to adapt to environmental changes.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Dehnhard Nina

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

The main aim of this project is to study the impact of interactions between natural stressors and anthropogenic stress, caused by environmental contamination with OHCs, on the health of nestling birds of prey in (sub)Arctic regions. Birds of prey from (sub)Arctic regions have several characteristics that make them very useful to study OHC exposure in combination with natural stressors (see methodology).

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Covaci Adrian
• Co-promoter: Jaspers Veerle

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

The evolution of parental care is central to our understanding of among other social systems and sexual selection, which are main areas of research in evolutionary biology. However, virtually nothing is known about its genetic architecture. Parental care includes complex parent-offspring interactions and its evolution therefore depends on the evolution of two traits, parental provisioning and offspring begging. Both behaviours should ultimately become genetically correlated, since changes in one trait exert a selective pressure on the evolution of the other. To complicate matters, the evolution of parental care is also shaped by a conflict of interest over the degree of provided parental investment between parents and offspring. My proposed research project aims at studying the genetic basis and consequences of co-adaptation between parental provisioning and offspring begging. In a first step, I will separately look at the heritability and phenotypic plasticity of both, parental provisioning and offspring begging, which set the basis for any co-evolutionary process. Next, I will focus on the co-variance of both traits using an intra-individual and an intra-family approach. Finally, I will study the functional consequences of co-adaptation for both parents and offspring, which will also improve our understanding of who is winning the parent-offspring conflict.

Researcher(s)

• Promoter: Müller Wendt
• Co-promoter: Eens Marcel
• Fellow: Estramil Natalia

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

The general aim of the proposal is to test if the supplementation of carotenoids and/or cholesterol can promote the synthesis of T that regulate the uptake of carotenoids in the cells of the trait. This is in line with the finding that carotenoids can regulate the steroidogenic activity in humans (Wickenheisser et al. 2005; Angwafor and Anderson 2008) and other mammals (Folman et al. 1983; Chew 1993; Chew et al. 2001; Campbell et al. 2006). Indirect evidence shows that providing zebra finches Taeniopygia guttata with carotenoids enhances their escape flight ability (Blount and Matheson 2006), suggesting that carotenoids may stimulate the production of androgen with anabolic effects on the flight muscles. Similar evidence comes from a recent discovery that European starlings Sturnus vulgaris supplemented with carotenoids increase their song rate and that starlings supplemented with both carotenoids and T show an enhanced nest-oriented song compared to birds treated just with T (VanHout, Eens and Pinxten 2011). Moreover providing cholesterol to zebra finches enhances bill carotenoids (McGraw and Parker 2006) suggesting a promotion of T by cholesterol is the first step of the complex steroidogenic process.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Casagrande Stefania

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

The main aim of the proposed research is to study exposure and effects of organic pollutants in predatory birds, using the white-tailed eagle (Haliaeetus albicilla; WTE) as a model species. The proposed research can be subdivided in several objectives. Firstly, I will study exposure through the development of physiologically based pharmacokinetic (PBPK) bioaccumulation models. Since a high amount of species-specific information is required to develop such a model, I have chosen the WTE as a model species. This species has been monitored for years through international collaborations and I have access to databases providing sufficient information for the first objective (see methodology). The second objective aims to study the effects from the physiological up to the population level. The last objective deals with the study of exposure to organic pollutants in the light of varying climate and feeding conditions over time.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Covaci Adrian
• Fellow: Jaspers Veerle

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Using a pedigreed captive canary population, the proposed project applies a quantitative genetic approach to the mechanisms and function of bird song, a trait playing an important role in the study of sexual selection. We will estimate the genetic inheritance of bird song as well as potential environmental influences. In order to test predictions of evolutionary theory in the context of sexual selection, we will investigate whether bird song indicates genetic and/or environmental quality, and analyze genetic correlations among song parameters, condition and immunocompetence. Finally, we apply a quantitative genetic approach to the endocrine regulation of corticosterone and testosterone, as the evolution of the traits studied here may depend on indirect selection on the underlying mechanisms.

Researcher(s)

• Promoter: Müller Wendt
• Co-promoter: Eens Marcel

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Song in songbirds as a model system for studying complex behaviours: an integration of ecological, physiological and neurobiological data in an evolutionary framework [and also Causes and consequences of variation in complex secondary sexual song characteristics: a longitudinal and multidisciplinary approach by integrating behavioural, physiological and molecular data.

Researcher(s)

• Promoter: Eens Marcel

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Interactions between caring parents and their offspring are one of the most widespread social behaviours in animals. These parent-offspring interactions involve two parties and its evolution is, therefore, dependent on the evolution of two traits, parental provisioning and offspring begging. From a quantitative genetic perspective both behaviours should co-adapt, which should ultimately lead to (genetic) co-variation. But evidence for co-adaptation, its underlying genetics and the potential fitness consequences is as yet very limited, especially in natural populations. Furthermore, co-adaptation is not the only process shaping the evolution of parental care. Its evolution is also affected by a conflict of interest over the amount of parental care, since offspring is selected to seek greater parental investment than the parents are selected to give. In my PhD-project I will integrate approaches from behavioural ecology and quantitative genetics to study: (a) the (genetic) correlation between offspring solicitation and parental provisioning genes in a natural population of blue tits (b) the potential fitness consequences of a disruption of this correlation for both parents - in the light of the sexual conflict over parental care (c) whether maternal effects play a role in shaping the co-evolution of offspring solicitation and parental provisioning."

Researcher(s)

• Promoter: Müller Wendt
• Co-promoter: Eens Marcel
• Fellow: Lucass Carsten

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

This project represents a research contract awarded by the University of Antwerp. The supervisor provides the Antwerp University research mentioned in the title of the project under the conditions stipulated by the university.

Researcher(s)

• Promoter: Eens Marcel

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

A lot of research has already been performed on the function of maternal hormones in the eggs of birds. The observed effects have however always been described independently of the environment the birds live in, although an effect might be positive in one environment while being negative in another. This makes the environment an essential factor in this research topic. In addition, studies so far have mainly been done from the chicks' point of view. Nevertheless, what is positive for the parents does not necessarily need to be positive for the young, and vice versa. Despite this, the effects on the parents have received little attention and need to be studied in greater detail. Combining these two main principles, the adaptive value of maternal hormone deposition can only be determined in this broader context, with environment-dependent hormone deposition possibly being a mothers' optimal strategy to maximise her fitness.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Vergauwen Jonas

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

This project represents a formal research agreement between UA and on the other hand KMDA. UA provides KMDA research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Stevens Jeroen
• Co-promoter: Stevens Jeroen
• Fellow: Staes Nicky

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

The evolution of parental care is central to our understanding of among other social systems and sexual selection, which are main areas of research in evolutionary biology. However, virtually nothing is known about its genetic architecture. Parental care includes complex parent-offspring interactions and its evolution therefore depends on the evolution of two traits, parental provisioning and offspring begging. Both behaviours should ultimately become genetically correlated, since changes in one trait exert a selective pressure on the evolution of the other. To complicate matters, the evolution of parental care is also shaped by a conflict of interest over the degree of provided parental investment between parents and offspring. My proposed research project aims at studying the genetic basis and consequences of co-adaptation between parental provisioning and offspring begging. In a first step, I will separately look at the heritability and phenotypic plasticity of both, parental provisioning and offspring begging, which set the basis for any co-evolutionary process. Next, I will focus on the co-variance of both traits using an intra-individual and an intra-family approach. Finally, I will study the functional consequences of co-adaptation for both parents and offspring, which will also improve our understanding of who is winning the parent-offspring conflict.

Researcher(s)

• Promoter: Eens Marcel
• Promoter: Müller Wendt
• Co-promoter: Eens Marcel
• Co-promoter: Müller Wendt
• Fellow: Estramil Natalia

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

In this study we examine maternal yolk hormones in the budgerigar (Melopsittacus undulatus), which give the female the ability to modify offspring phenotype to their future environment. We study the variation of maternal yolk hormones within and between clutches. We search evidence for possible mechanism of variable hormone deposition in the yolk and we study the effects of variable deposition for the offspring, in the short term as well as in the long term.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Pinxten Annie
• Fellow: Lahaye Stefanie

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

The main focus of this project is to asses the signal value of carotenoid colouration in relation to oxidative stress levels and diet quality in the great tit (Parus major). The great tit has a carotenoid based signal, namely the yellow breast colour. The brightness of this colour is linked to the condition and the quality of the bearer. The research will be conducted in a well known metal pollution gradient. We expect that birds in polluted areas will fade under the influence of metal induced oxidative stress and/or lower food quality.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Geens Ann

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

During this project we aim to study, in an integrated manner, the causes and consequences of variation in a wide range of song characteristics in the great tit. By utilising automatic song recording systems, we will register and quantify all possible aspects of the song of at least 200 free-living great tits in full detail. We aim to monitor as many males as possible during their life time. The unique dataset obtained in this way will be used for further cross-sectional and longitudinal analyses. We will study the causes and consequences in song behaviour in an integrated way by using physiological, immuno-endocrine, and state-of-the-art molecular techniques, as well as personality and learning tests and heredity analyses.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Pinxten Annie

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

This project represents a research contract awarded by the University of Antwerp. The supervisor provides the Antwerp University research mentioned in the title of the project under the conditions stipulated by the university.

Researcher(s)

• Promoter: Eens Marcel

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

This project represents a research agreement between the UA and on the onther hand IWT. UA provides IWT research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Van Hout Alain

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

The central aim of this postdoc research project is to examine the sources of variation in maternal investment in eggs of rockhopper penguins (Eudyptes chrysocome) and potential effects of such investment on embryonic survival an development. We will study this variation at all possible levels: within the breeding population (i.e. among clutches), within clutches and among breeding seasons and different population.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Poisbleau Maud

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

This is a fundamental research project financed by the Research Foundation - Flanders (FWO). The project was subsidized after selection by the FWO-expert panel.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Müller Wendt

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Eens Marcel

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

A lot of research has already been performed on the function of maternal hormones in the eggs of birds. The observed effects have however always been described independently of the environment the birds live in, although an effect might be positive in one environment while being negative in another. This makes the environment an essential factor in this research topic. In addition, studies so far have mainly been done from the chicks' point of view. Nevertheless, what is positive for the parents does not necessarily need to be positive for the young, and vice versa. Despite this, the effects on the parents have received little attention and need to be studied in greater detail. Combining these two main principles, the adaptive value of maternal hormone deposition can only be determined in this broader context, with environment-dependent hormone deposition possibly being a mothers' optimal strategy to maximise her fitness.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Vergauwen Jonas

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

The main focus of this project is to asses what the effects are of testosterone (T) on the morphology, physiology and behaviour in the female great tit (Parus major) and in the end on their fitness. Additionally I will investigate if T-concentrations in females are a consequence of a correlated response on T-concentrations in males. At the end of this project I will integrate my results with the current literature on T in female birds. By combining the results of these studies we can generate higher order of conclusions on the relationship between T and behavioural, physiological and morphological parameters.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: De Jong Berber

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

The research objectives are - Examine the factors that determine concentrations of organic pollutants in feathers; - Study the relationship between levels of organic pollutants and effects in individual birds; - Assess sources of geographical variation for contamination with organic pollutants using feathers; - Integrate all results to resolve which factors explain variation in contamination among bird species.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Jaspers Veerle

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Brominated fire retardants (BFRs) are a large group of chemicals which are widely used in different materials (e.g. electronics, textile). There is however a lack of information on the toxicological profile of these pollutants. The aims of this research project are to study 1) maternal transfer, 2) reproductive, behavioural and health effects and 3) toxicokinetics and metabolism of brominated fire retardants (BFRs). To accomplish these objectives, both experimental and field studies will be performed in different songbird species.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Van Den Steen Evi

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

The main focus of this project is to asses the signal value of carotenoid colouration in relation to oxidative stress levels and diet quality in the great tit (Parus major). The great tit has a carotenoid based signal, namely the yellow breast colour. The brightness of this colour is linked to the condition and the quality of the bearer. The research will be conducted in a well known metal pollution gradient. We expect that birds in polluted areas will fade under the influence of metal induced oxidative stress and/or lower food quality.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Geens Ann

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

In this study we examine maternal yolk hormones in the budgerigar (Melopsittacus undulatus), which give the female the ability to modify offspring phenotype to their future environment. We study the variation of maternal yolk hormones within and between clutches. We search evidence for possible mechanism of variable hormone deposition in the yolk and we study the effects of variable deposition for the offspring, in the short term as well as in the long term.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Pinxten Annie
• Fellow: Lahaye Stefanie

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Pinxten Annie
• Co-promoter: Eens Marcel
• Fellow: De Jong Berber

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

The aim of this project is to address gaps in our understanding of intraspecific variation in animal behaviour, especially the movement behaviour of small bentic freshwater fish species. To achieve this, the proposed study integrates two closely-linked research components.

Researcher(s)

• Promoter: Eens Marcel

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Van Hout Alain

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

The main focus of this project is to asses the signal value of carotenoid colouration in relation to oxidative stress levels and diet quality in the great tit (Parus major). The great tit has a carotenoid based signal, namely the yellow breast colour. The brightness of this colour is linked to the condition and the quality of the bearer. The research will be conducted in a well known metal pollution gradient. We expect that birds in polluted areas will fade under the influence of metal induced oxidative stress and/or lower food quality.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Geens Ann

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

The objectives of the project are to investigate (i) the effect of malaria prevalence on sexual signalling; (ii) the potential physiological and genetic mechanisms that are responsible for the maintenance of reliable signalling of parasite levels; (iii) the interspecific relationship between disease risk and mating system using primates and birds; and (iv) the evolutionary relationship between parasite and host life history traits by focusing on the perspective of malaria parasites.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Garamszegi Laszlo

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Pinxten Annie
• Fellow: Van Hout Alain

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Van Der Linden Annemie

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Van Dongen Margot

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Human activities have lead to the release and worldwide distribution of various hazardous substances, such as heavy metals and persistent organic pollutants (POPs). Growing concern about possible harmful effects of these pollutants has encouraged the development of several biomonitoring programs. At the moment there is a lack of scientific data concerning (1) the occurrence of many pollutants in biota and (2) the usefulness of various bird species as a bio-indicator species. However, such research is necessary regarding birds and other animal groups. In my project, I will assess the concentrations of various heavy metals and POPs in internal tissue samples, feathers, blood samples and eggs of different bird species. Relatively little information is available about concentrations of recent POPs, such as PBDEs (fire retardants) and PFOS in terrestrial vertebrate animals (including birds) in Flanders. Moreover no comparative studies have investigated the usefulness of different bird species as a biomonitor of pollution with POPs and heavy metals. Brief, I will investigate whether there are differences in contamination between study areas, whether non-invasive biomonitoring methods (i.e. feathers) can be developed and whether differences in contamination levels between bird species of the same area can be related tot different feeding strategies, ecology, territory size etc. Finally, I will integrate the results of the different examinations to determine which bird species appear to be the most suitable biomonitors for both types of pollutants.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Jaspers Veerle

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

The aim of this project is to investigate the role of the 'male' sex hormone testosterone (T) in female vertebrates. This will be accomplished by (1) studying the effects of experimentally elevated T levels on behavioural, reproductive and physiological parameters in female great tits and European starlings in natural and controlled experimental conditions and (2) investigating to which extent T-sensitive parameters affect female fitness.

Researcher(s)

• Promoter: Eens Marcel

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Van Coillie Sara

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

In this project we examine the relative importance of a great variety of characteristics (song, personality, colour and plumage characteristics, morphological characteristics) in the context of mate choice and intrasexual competition. Furthermore, we will invest whether females invest more in reproduction if they are mated to an attractive partner (assessed by secondary sexual characters). We will examine whether females adapt the deposition of maternal hormones in their eggs in function of the quality of their mate.

Researcher(s)

• Promoter: Eens Marcel

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Maerten Evelien

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Müller Wendt

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Knaepkens Guy

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

The scope of this proposal is to study in an integrated and compre- hensive manner the role of carotenoids in all 3 above mentioned physiological functions (antioxidative potential, immuno-stimulation and expression of secondary sexual characteristics), with special attention on the possible trade-off among the different physiological functions of carotenoids. In concrete, we will study the mitigable effect of carotenoids on the amount and the effects of lead-induced oxidative stress in birds. Special attention will be given to the pos- sibility that the allocation of carotenoids as antioxidants may influ- ence the other functions of carotenoids. This proposal will thus contribute significantly to the study of carotenoid-based sexual traits as honest signals of condition and health status in birds and other vertebrates. Finally, we will investigate whether interspecific differ- ences in susceptibility to lead poisoning are caused by differences in antioxidant levels among species, which has recently been suggested. The objectives of our proposal will be met with experiments under laboratory and natural conditions. In the field study, great tits will be used as model species. Because great tits readily use nest boxes, they can be easily manipulated and studied. Janssens et al. (2003a) have found that great tits are susceptible to heavy metal poisoning, which resulted in an impaired reproductive success. Finally, the great tit is one of the few bird species in which a conspicuous carotenoid- based coloration is developed already during the nestling stage, which arises from unmodified deposition of lutein and zeaxanthin (fschirren et al., 2003). These characteristics render the great tit a very suitable study species. Because great tits are difficult to study in laboratory conditions however, we will use the zebra finch (T aeniopygia guttata) as model species in the laboratory experiments. This small passerine is an important study species in behavioural ecological research and has been used previously by ETHOL to investigate the accumulation of lead in tissues and feathers (Dauwe et al. 2002, Snoeijs et al., in prep.)

Researcher(s)

• Promoter: Eens Marcel

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Human impact on the environment has increased dramatically over the last decades. The technological and industrial development has resulted in the release of numerous hazardous substances into the environment, which in many cases have been distributed worldwide. The occurrence of contaminants in the environment poses a genuine threat to the quality of ecosystems and the organisms that live there (Merian 1997). Although a wide variety of chemicals have been detected in environmental samples, environmental chemistry is still virtually limited to two major classes of chemicals, the heavy metals and the poly halogenated aromatic hydrocarbons (PHAHs; PeakalI1992). The exposure to contaminants can result in negative effects at all levels of biological organisation: from a biQchemical I response to a decrease in population numbers. Although effects on molecular or cellular level are in many cases easily i detectable and often have a clear dose-response relationship, the ecological relevance is often very low. Effects of pollutants on individual or population level on the other hand, have a much higher ecological significance. Especially the impairment of normal reproduction is very important from an ecological point of view. Moreover, because successful reproduction requires the integration of endocrine, physiological and behavioural processes, it is very sensitive to pollution. In recent years concern about the effect of environmental changes on male reproductive health has grown to become a major preoccupation in some developed countries (Tieleman et al. 1999, Telisman et al. ,2000, Hauser et al. 2002). Sperm quality may be a rapid-measurement endpoint biomarker for measuring sublethal effects of chemical pollutants on reproduction (Boyle et al. 1992, Citutovic et al. 1993). Because a reduction in sperm quality does not have to result in an impaired reproductive success, sperm quality may function as an early warning system (Bonde et al. 1999). Studies on the effects of pollutants, both spermatotoxic chemicals and endocrine disruptors, on the sperm quality of mammals have increased markedly. Although several studies have shown that PHAHs and heavy metals may negatively affect sperm quality in mammals (Apostoli et al. 1998), few studies however have examined the effects of contaminants on avian §perm. In behavioural ecological studies and in poultry research a number of techniques have been developed and used to determine the sperm quality of birds non-invasively. An interesting, indirect measure of sperm quality is the number of spermatozoa in the perivitelline layer (membrane surrounding the yolk) of the egg (Birkhead 1989, Wishart 1997). Recently we have shown in a field study that heavy metal pollution can have a negative effect on the number of spermatozoa in blue tit (Parus caeruleus) eggs (Dauwe et al. 2004). In the framework of this proposal, this technique will be evaluated in more detail as a possible non-destructive indicator for the effects of contaminants on the sperm quality and the reproductive success. To do so, all factors that may have an influence on the number of spermatozoa in the egg will be studied. The possible effect of a reduced sperm quality on the re~roductive success (hatching success) will also be assessed. In this study we will use the zebra finch (Taeniopygia guttata) as model species, because they can be studied and bred relatively easily in captivity. Moreover, the zebra finch has been used intensively as model species in physiological, neurobiological and behavioural research (Scheuhammer 1996, Zann 1996). Finally, the number of spermatozoa in zebra finch eggs have already been used to determine sperm quality in numerous studies on sperm competition in birds (see Birkhead 1989). To meet the objectives of this proposal, the effect of lead and PCB 153 on the sperm quality of zebra finches will be studied. We have chosen for these two pollutants because they are among the most widespread and

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Dauwe Tom

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Garamszegi Laszlo

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Human activities have lead to the release and worldwide distribution of various hazardous substances, such as heavy metals and persistent organic pollutants (POPs). Growing concern about possible harmful effects of these pollutants has encouraged the development of several biomonitoring programs. At the moment there is a lack of scientific data concerning (1) the occurrence of many pollutants in biota and (2) the usefulness of various bird species as a bio-indicator species. However, such research is necessary regarding birds and other animal groups. In my project, I will assess the concentrations of various heavy metals and POPs in internal tissue samples, feathers, blood samples and eggs of different bird species. Relatively little information is available about concentrations of recent POPs, such as PBDEs (fire retardants) and PFOS in terrestrial vertebrate animals (including birds) in Flanders. Moreover no comparative studies have investigated the usefulness of different bird species as a biomonitor of pollution with POPs and heavy metals. Brief, I will investigate whether there are differences in contamination between study areas, whether non-invasive biomonitoring methods (i.e. feathers) can be developed and whether differences in contamination levels between bird species of the same area can be related tot different feeding strategies, ecology, territory size etc. Finally, I will integrate the results of the different examinations to determine which bird species appear to be the most suitable biomonitors for both types of pollutants.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Jaspers Veerle

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Covaci Adrian
• Co-promoter: Neels Hugo
• Co-promoter: Schepens Paul

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Blue Tits (Parus caeruleus), as many other bird species, show great geographic variation in song from northern Europe to the Mediterranean region, North Africa and the Canary Islands. For example, Blue Tit repertoire size (the number of different song types per individual) differs noticeably among populations and ranges from 3 to 19 song types. In the north, songs that include a trill (a series of rapidly repeated notes) are widespread, whereas trills are rare in southern Spain and Corsica and have never been reported in North Africa and the Canary Islands. This variation in repertoire size and repertoire composition might be the result of geographic variation in local selection pressures. Possible selection pressures are sexual selection among Blue Tits and interspecific competition with a close competitor, the Great Tit (Parus major). Since both species are able to produce sounds with a similar syntax (non-trills) and frequency range, acoustic competition between these species could have caused a shift in Blue Tit song syntax. By using trills (of different syntax), Blue Tits can avoid the problem of being misidentified by Great Tits and therefore trilled song might reduce the probability of energy-demanding, aggressive territorial interactions with the more dominant Great Tits. Song variation could also be the result of sexual selection. Many bird species use different songs for inter 'and intrasexual communication and repertoire size may be related to the intensity of sexual selection or population density. In this study we will investigate whether trills and non-trills have different functional meanings, whether there is a relationship between repertoire size and the intensity of sexual selection, whether acoustic competition between Blue and Great Tits exists and whether there is a problem of misidentification between both species. In order to address these questions, different experiments will be performed in various populations (in Belgium and southern Spain) that differ in repertoire size and Great Tit density. Integration of the obtained behavioural, hormonal and morphological data will help to reveal the factors responsible for the origin and maintenance of song diversity among Blue Tit populations and might reveal important insights into Blue Tit communication strategies.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Gorissen Leen

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Secondary sexual characteristic give signals about individual quality to potential mates- 'good genes' hypothesis. In the last years there is a growing interest in studies concerning evolution of secondary sexual traits in female species. In the literature there are more and more evidence signifying that the mate choice may not be limited to the female, but may occur bilaterally. Furthermore it has been suggested that secondary sexual traits in females can have an adaptive value. This research aims at better understanding of the function of secondary sexual traits in female individuals. It focuses particularly on song behavior in female starlings, which until now has not been studied in detail, and explores its endocrine and neurobiological basis. The study gives attention to the seasonal and individual variation in female song activity. By investigating the relationships between song characteristics (song complexity and/or song frequency) and other characteristics (immunocompetence, weight, timing of pair formation and clutch size) this research provides a better view at the adaptive significance of variation in female song behavior. Preliminary results suggest that female song in this species might be used as an honest signal advertising quality.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Pinxten Annie
• Fellow: Zaprianova-Pavlova Denitza

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

In this study, the accumulation of lead in a small passerine songbird, the zebra finch, will be investigated. Special attention will be paid to the use of non-destructive techniques (e.g. eggs and feathers) to determine the exposure to lead. Also the effects of lead on reproductive behaviour and success of the zebrafinch will be investigated. Apart from general reproductive parameters, such as clutch size and hatching success, the effect of lead on sperm quality will also be assessed.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Dauwe Tom

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Various hazardous substances, such as heavy metals and persistent organic pollutants (POPs), have been released into the environment, as a consequence of human activities and have been distributed worldwide. Growing concern about possible harmful effects of these pollutants has lead to the development of several biomonitoring programs. At the moment there is a lack of scientific data concerning (1) the occurrence of many pollutants in biota and (2) the usefulness of various bird species as bio-indicator species, although such research is necessary regarding birds and other animal groups. In my project, I will assess the concentrations of various heavy metals and POPs in internal tissue samples, feathers, blood samples and eggs of different bird species who live in the same study area, but vary in food preferences, ecology, territory size, body size ' Samples will be collected in two different study areas: one urban and highly polluted area (Hoboken-Wilrijk) and one rural area (presumably Peer). I will investigate whether there are differences in contamination between the two study areas, whether non-invasive biomonitoring methods can be developed, whether differences in contamination levels between bird species of the same area can be related tot different feeding strategies, ecology, territory size' and whether relations exist between concentrations of pollutants and biomarker responses. Finally, I will examine which bird species appear to be the most suitable biomonitors for both types of pollutants.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Jaspers Veerle

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Garamszegi Laszlo

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Several models of sexual selection predict that females choose males of high quality, an attribute that can be inherited by their offspring wich in turn enhances their survival (good genes models), on the basis of secondary sexual traits. However, over the years, it has been difficult to define this quality. In 1982, Hamilton and Zuk (1982) proposed that the resistance to infections and diseases (immunocompetence) could be used by females to choose a mate. For a few years now, possible tradeoffs between the individual immune system and fitness related traits like reproductive efforts and secondary sexual traits (ecological immunology) have become also more of interest.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Pinxten Annie
• Fellow: Snoeijs Tinne

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Van Der Linden Annemie
• Fellow: Van Meir Vincent

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

In thus study intrasexual and intersexual behavioural reproductive strategies of chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) will be studied in captivity and compared. On the other hand, the physiology of sperm production will be studied in both species. This will be useful to understand the differences in social organization of the of the two species.

Researcher(s)

• Promoter: Eens Marcel
• Promoter: Verheyen Rudi
• Fellow: Stevens Jeroen

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Pinxten Annie
• Fellow: Custers Inge

Research team(s)

Project type(s)

• Research Project

Abstract

In many primates, the mother is the primary caretaker. A mother, who can balance her investment in such a way as to promote her infant's independence without jeopardizing its survival, will deplete her energy reserves less en will be able to start reproducing within a shorter period of time. How much a mother will invest in her offspring will depend upon her age, dominance position and parity. Other factors that can influence maternal behaviour are the sex of the offspring and the absence or presence of siblings. Apart from these individual factors, species-specific characteristics of the social organization and mating system of a species will influence maternal behaviour. Although the mother-infant bond is the primary social relationship among primates, research on the relation between social organization, mating system and maternal behaviour on the one hand and the relation between maternal behaviour and development of infants on the other, is rare. To gain more insight concerning female reproductive strategies in primates, research on intra- and interspecific variation of maternal behaviour and investment is necessary. Two species that lend themselves perfectly for this research are the bonobo (Pan paniscus) and the chimpanzee (Pan troglodytes). Behavioural observations will allow us to determine the maternal styles and follow the development of behaviour of bonobo and chimpanzee infants. More specifically we will investigate the relation between the ontogeny of behaviour and the maternal style. The influence of individual varying factors of the mothers and the species-specific characteristics of the two Pan-species on maternal behaviour or style will be investigated. The data will be used to test the hypothesis that interspecific differences in maternal styles are an adaptive response to differences in social organization. Additionally, studbook analyses (ex. calculation of birth sex ratios, interbirth intervals, mortality and survival of infants) will allow us to compare the reproductive success and reproductive strategies of female bonobos and chimpanzees.

Researcher(s)

• Promoter: Eens Marcel
• Promoter: Verheyen Rudi
• Co-promoter: Van Elsacker Linda

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Eens Marcel

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Blue Tits (Parus caeruleus), as many other bird species, show great geographic variation in song from northern Europe to the Mediterranean region, North Africa and the Canary Islands. For example, Blue Tit repertoire size (the number of different song types per individual) differs noticeably among populations and ranges from 3 to 19 song types. In the north, songs that include a trill (a series of rapidly repeated notes) are widespread, whereas trills are rare in southern Spain and Corsica and have never been reported in North Africa and the Canary Islands. This variation in repertoire size and repertoire composition might be the result of geographic variation in local selection pressures. Possible selection pressures are sexual selection among Blue Tits and interspecific competition with a close competitor, the Great Tit (Parus major). Since both species are able to produce sounds with a similar syntax (non-trills) and frequency range, acoustic competition between these species could have caused a shift in Blue Tit song syntax. By using trills (of different syntax), Blue Tits can avoid the problem of being misidentified by Great Tits and therefore trilled song might reduce the probability of energy-demanding, aggressive territorial interactions with the more dominant Great Tits. Song variation could also be the result of sexual selection. Many bird species use different songs for inter 'and intrasexual communication and repertoire size may be related to the intensity of sexual selection or population density. In this study we will investigate whether trills and non-trills have different functional meanings, whether there is a relationship between repertoire size and the intensity of sexual selection, whether acoustic competition between Blue and Great Tits exists and whether there is a problem of misidentification between both species. In order to address these questions, different experiments will be performed in various populations (in Belgium and southern Spain) that differ in repertoire size and Great Tit density. Integration of the obtained behavioural, hormonal and morphological data will help to reveal the factors responsible for the origin and maintenance of song diversity among Blue Tit populations and might reveal important insights into Blue Tit communication strategies.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Gorissen Leen

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Vervaecke Hilde

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Pinxten Annie
• Fellow: Zaprianova-Pavlova Denitza

Research team(s)

Project type(s)

• Research Project

Abstract

The existing individual variation in behaviour can lead to variation in fitness. Hormones often form the basis of many behaviours. Individual differences in hormone concentrations thus can lead to variation in behaviour, and fitness. Being the most important male sex hormone, testosterone seems to have a strong influence on social and reproductive behaviour of male vertebrates. In great apes however, the relationship between testosterone and male social behaviour is not yet clear. Moreover, very little is known about the relationship between testosterone and behaviour of female great apes. In this study the influence of testosterone on the individual fitness will be investigated by studying the relationship between testosterone and some behavioural aspects of the bonobo (Pan paniscus). In a first part, the relationship between testosterone and the individual aggressiveness and dominance rank will be studied in both sexes. A second part will treat the relationship between testosterone and sexual behaviour of both males and females. A last part will deal with extended comparative studies on testosterone. A first, intraspecific comparison will be made between testosterone concentrations of captive and wild bonobos. A second, interspecific part will compare the testosterone concentrations of female bonobos and chimpanzees (Pan troglodytes).

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Sannen Adinda

Research team(s)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Doutrelant Claire

Research team(s)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Blust Ronny
• Co-promoter: De Coen Wim
• Co-promoter: Eens Marcel
• Co-promoter: Schepens Paul
• Co-promoter: Verhagen Ron

Research team(s)

Project type(s)

• Research Project

Abstract

In this project we will use molecular techniques to study reproductive behaviour of birds. In the framework of ongoing sexual selection research, we will determine the exact reproductive success of birds using microsatellites, and we will study factors that influence the sex ratio within a clutch.

Researcher(s)

• Promoter: Eens Marcel

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

In this project, mechanistic (proximate) and ultimate aspects of sexual selection are integrated and insights and techniques from different disciplines are incorporated to get to know more about the development of secondary sexual characters and the selective forces which may have led to their evolution

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Eens Marcel

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

The first objective of this project is to evaluate whether bird feathers of terrestrial songbird species (Great and Blue tit) can be used as indicators of heavy metal pollution in terrestrial ecosystems. To realize this objective we will establish 5 nestbox sites along a pollution gradient away from the pollution source (a non-ferro industrial plant) and collect the outermost tail feathers of both adult tits and nestlings. The second objective is to study the relationship between levels of heavy metals in bird feathers and the possible effects of heavy metal pollution on the reproduction and health status of songbirds by integrating behavioral, reproductive, morphological, physiological, immunological and endocrinological parameters.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Janssens Ellen

Research team(s)

Project type(s)

• Research Project

Abstract

Several models of sexual selection predict that females choose males of high quality, an attribute that can be inherited by their offspring wich in turn enhances their survival (good genes models), on the basis of secondary sexual traits. However, over the years, it has been difficult to define this quality. In 1982, Hamilton and Zuk (1982) proposed that the resistance to infections and diseases (immunocompetence) could be used by females to choose a mate. For a few years now, possible tradeoffs between the individual immune system and fitness related traits like reproductive efforts and secondary sexual traits (ecological immunology) have become also more of interest.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Snoeijs Tinne

Research team(s)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Van Meir Vincent

Research team(s)

Project type(s)

• Research Project

Abstract

Several studies indicate that testosterone influences reproductive and social behaviour, the expression of secondary sexual traits and the immune system. The possible effects of testosterone will be investigated coherently by following a double strategy. First the relations with the natural testosterone levels will be described. Secondly the consequences of experimentally elevated testosterone concentrations will be studied.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Pinxten Annie
• Fellow: Van Duyse Els

Research team(s)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Knaepkens Guy

Research team(s)

Project type(s)

• Research Project

Abstract

In recent years, bird feathers have been used as an indicator tissue of metal exposure in birds. Bird feathers are ideal for assessment of heavy metals because they accumulate certain heavy metals in proportion to blood levels at the time of feather formation. Studying the effect of heavy metals on terrestrial songbirds by integrating reproductive, endocrinological, immunological and behavioural parameters is innovating.

Researcher(s)

• Promoter: Eens Marcel

Research team(s)

• Behavioural Ecology & Ecophysiology

Project type(s)

• Research Project

Abstract

The spatial structure of natural populations is determined by the degree of interaction of individuals or social groups that occupy different parts of the habitat. The most influential factor in this spatial structuring is individual dispersal behaviour, defined as the movement between site of birth and site of reproduction. The aim of this project is to obtain more insight in the role of environmental variation and social structure in the dispersal process of a model species, the Great Tit. An essential element is the quantification of parameters of individual quality and condition.

Researcher(s)

• Promoter: Matthysen Erik
• Co-promoter: Eens Marcel

Research team(s)

Project type(s)

• Research Project

Abstract

The first objective of this project is to evaluate whether bird feathers of terrestrial songbird species (Great and Blue Tit) can be used as indicators of heavy metal pollution. To this end we will establish several nestbox populations along a pollution gradient away from a pollution source (a non-ferro industrial plant) and collect the outermost tail feathers of both adult and nestling tits. The second objective is to study the relationship between levels of heavy metals in bird feathers and the possible effects of heavy metal pollution on the reproduction and health status of songbirds by integrating behavioral, reproductive, morphological, physiological and immuno-endocrinological parameters.

Researcher(s)

• Promoter: Eens Marcel

Research team(s)

Project type(s)

• Research Project

Abstract

During the last two decades, birdsong has become a leading model in behavioral neuroscience to investigate the neural mechanisms that underlie defined species-specific behaviors by members of the order Passeriformes. These vocalizations are usually emitted by the male, in the context of territorial defense, courtship and mating. Song production is sensitive to gonadal steroid hormones, and it is generally accepted that, in adults, a rise in circulating testosterone level consecutive to increased day length stimulates singing. At the brain level, birdsong is controlled by discrete clusters of neurons, the song control nuclei, that coordinate environmental and endocrine cues with the appropriate vocal output. The neural web underlying singing behavior is also sensitive to gonadal steroid hormones and presents extensive plasticity. In general, many factors can be used to characterize songs (number of syllable types, song rate, number of new songs in open-ended learner, variation in perceptual memory) and the song control nuclei (gross volume, cell number, cell size, afferent and efferent connections, neurogenesis, neuritogenesis,...) and all these aspects should be considered in order to determine the relations between singing behavior and the song control system. This has not been achieved in any model species to this date and thus, the functional significance of brain plasticity remains partly unclear. Our project is designed to address this question.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Absil Philippe

Research team(s)

Project type(s)

• Research Project

Abstract

To the best of our knowledge, information about the extent and consequences of genetic erosion in endangered and rare fish species in the Flanders is lacking. Since the greatest understanding of molecular information will come when it is used in conjunction with ecological, demographic, and physiological data, we will link, in the present project proposal, expertises from population ecology, population genetics and ecophysiology to study the extent and consequences of genetic erosion in rare and endangered fish species. The obtained information will be useful for (1) documenting the genetic isolation and distinction of (vanishing) populations; (2) documenting how the genetic structure affects the responses of individuals and populations to stress; (3) develop measures to prevent (the consequences of) genetic pauperization; (4) tracing corridors of dispersal among populations; (5) identifying populations that might provide the source material for augmentation or reintroduction programs.

Researcher(s)

• Promoter: Eens Marcel

Research team(s)

Project type(s)

• Research Project

Abstract

In this project we try to elucidate the endocrine basis for individual variation in mate reproductive behaviour, reproductive success and survival in the European sterling (Sturnus vulgaris), a facultatively polygynous passerine.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Pinxten Annie
• Fellow: De Ridder Elke

Research team(s)

Project type(s)

• Research Project

Abstract

The existing individual variation in behaviour can lead to variation in fitness. Hormones often form the basis of many behaviours. Individual differences in hormone concentrations thus can lead to variation in behaviour, and fitness. Being the most important male sex hormone, testosterone seems to have a strong influence on social and reproductive behaviour of male vertebrates. In great apes however, the relationship between testosterone and male social behaviour is not yet clear. Moreover, very little is known about the relationship between testosterone and behaviour of female great apes. In this study the influence of testosterone on the individual fitness will be investigated by studying the relationship between testosterone and some behavioural aspects of the bonobo (Pan paniscus). In a first part, the relationship between testosterone and the individual aggressiveness and dominance rank will be studied in both sexes. A second part will treat the relationship between testosterone and sexual behaviour of both males and females. A last part will deal with extended comparative studies on testosterone. A first, intraspecific comparison will be made between testosterone concentrations of captive and wild bonobos. A second, interspecific part will compare the testosterone concentrations of female bonobos and chimpanzees (Pan troglodytes).

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Sannen Adinda

Research team(s)

Project type(s)

• Research Project

Abstract

In the face of continuous threats from parasites, hosts have evolved an elaborate series of preventative and controlling measures, the immune system, in order to reduce the fitness costs of parasitism. Recently, evolutionary ecologists are starting to pay more attention to immunology. The aim of this project is to develop immuno-endocrine techniques and to apply them for eco-ethological research (sexual selection, life history strategies) on passerine birds.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Snoeijs Tinne

Research team(s)

Project type(s)

• Research Project

Abstract

The first objective of this project is to evaluate whether bird feathers of terrestrial songbird species (Great and Blue tit) can be used as indicators of heavy metal pollution in terrestrial ecosystems. To realize this objective we will establish 5 nestbox sites along a pollution gradient away from the pollution source (a non-ferro industrial plant) and collect the outermost tail feathers of both adult tits and nestlings. The second objective is to study the relationship between levels of heavy metals in bird feathers and the possible effects of heavy metal pollution on the reproduction and health status of songbirds by integrating behavioral, reproductive, morphological, physiological, immunological and endocrinological parameters.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Janssens Ellen

Research team(s)

Project type(s)

• Research Project

Abstract

In this project, mechanistic (proximate) and ultimate aspects of sexual selection are integrated and insights and techniques from different disciplines are incorporated to get to know more about the development of secondary sexual characters and the selective forces which may have led to their evolution.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Eens Marcel

Research team(s)

Project type(s)

• Research Project

Abstract

Animals which live in permanent social groups have to deal with a high level of intraspecific competition. Often this competition is expressed as agonistic interactions between the group members. One strategy to cope with this kind of aggression is reconciliation. Affiliative interactions between former opponents seem to reduce the stress-response and restore the mutual tolerance. Although bonobos (Pan paniscus) are often regarded as real 'masters' of reconciliation, they were rarely the subject of research on peacemaking behaviour. A preliminary study revealed some indications that bonobos seem to cope with stress in a very individual manner. To have a clear insight into the inter-individual variation we have to take a closer look at the corresponding stress-physiology. The object in view is to formulate a proximate explanation for the extent to which bonobos use reconciliation. To realise this goal we endeavour to integrate behavioural and endocrinological data. Regarding the ethological part we will evaluate the effect of some variables on the conciliatory tendency. We especially expect rank, sex, kin and reproductive state of the females to be influential. The three most relevant methods for studying reconciliation-patterns in bonobos are the 'PC/MC'-method, the 'Rate'-method and the 'Time Rule'-method. The second part of this study investigates a possible correlation between the previous parameters and levels of a specific stress-hormone. The available method to test for this correlation is the determination of cortisol baseline levels in the urine of individual bonobos. The relation between conciliatory tendency and discussed variables on the one hand and the relation between cortisol-levels and the same parameters on the other hand allow us to connect the behavioural component with the endocrinological one.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Meuleman Birgen

Research team(s)

Project type(s)

• Research Project

Abstract

Several studies indicate that testosterone influences reproductive and social behaviour, the expression of secondary sexual traits and the immune system. The possible effects of testosterone will be investigated coherently by following a double strategy. First the relations with the natural testosterone levels will be described. Secondly the consequences of experimentally elevated testosterone concentrations will be studied.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Pinxten Annie
• Fellow: Van Duyse Els

Research team(s)

Project type(s)

• Research Project

Abstract

The existing individual variation in behaviour can lead to variation in fitness. Hormones often form the basis of many behaviours. Individual differences in hormone concentrations thus can lead to variation in behaviour, and fitness. Being the most important male sex hormone, testosterone seems to have a strong influence on social and reproductive behaviour of male vertebrates. In great apes however, the relationship between testosterone and male social behaviour is not yet clear. Moreover, very little is known about the relationship between testosterone and behaviour of female great apes. In this study the influence of testosterone on the individual fitness will be investigated by studying the relationship between testosterone and some behavioural aspects of the bonobo (Pan paniscus). In a first part, the relationship between testosterone and the individual aggressiveness and dominance rank will be studied in both sexes. A second part will treat the relationship between testosterone and sexual behaviour of both males and females. A last part will deal with extended comparative studies on testosterone. A first, intraspecific comparison will be made between testosterone concentrations of captive and wild bonobos. A second, interspecific part will compare the testosterone concentrations of female bonobos and chimpanzees (Pan troglodytes).

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Sannen Adinda

Research team(s)

Project type(s)

• Research Project

Abstract

In this project, the relationships between mate 'brightness' (measured by song and plumage characteristics) and the resistance to parasites will be studied by several complementory approaches, both empirical and experimental.

Researcher(s)

• Promoter: Eens Marcel

Research team(s)

Project type(s)

• Research Project

Abstract

In this project we try to elucidate the endocrine basis for individual variation in mate reproductive behaviour, reproductive success and survival in the European sterling (Sturnus vulgaris), a facultatively polygynous passerine.

Researcher(s)

• Promoter: Eens Marcel
• Co-promoter: Pinxten Annie
• Fellow: De Ridder Elke

Research team(s)

Project type(s)

• Research Project

Abstract

Song is a well-studied secondary sexual characteristic in birds. We will study the factors which cause individual variation in song. Moreover we will investigate the consequences of individual variation in song behaviour on survival and reproductive success.

Researcher(s)

• Promoter: Eens Marcel
• Fellow: Van Duyse Els

Research team(s)

Project type(s)

• Research Project

Abstract

Detailed quantitative song analyses are used to (1) test predictions of the intersexual selection hypothesis (2) study causes of intraspecific variation in song characteristics (3) compare the singing behaviour of the European and spotless starling.

Researcher(s)

• Promoter: Eens Marcel

Research team(s)

Project type(s)

• Research Project

Abstract

The aim of this study is (1) to test experimentally several predictions of the 'intersexual selection' hypothesis; (2) to study the causes of intraspecific variation in song characteristics; (3) to compare the song and reproductive behaviour of the European and Spotless starling.

Researcher(s)

• Promoter: Eens Marcel

Research team(s)

Project type(s)

• Research Project

Abstract

The aim of this project is to examine the function and evolution of complex song repertoires in 'continuous singers'.

Researcher(s)

• Promoter: Verheyen Rudi
• Fellow: Eens Marcel

Research team(s)

Project type(s)

• Research Project