Research Stefan Van Dongen

Abstract

The human body is a complex bio-mechanical system that exhibits many variations in geometry and movements. Advancements in 3D scanning and 3D modeling allow to construct precise and high-resolution models of the human body. Such a 3D model often contains more than 2GB of information such that recording, processing, transmission and data storage is labor and time intensive. In this project we acquire a 3D body scanner that captures the human body shape in high precision and with virtually no effort. The equipment will allow to register the human body with an accuracy of 1mm and up, at a frame rate of 10 3D scans per second. This so called 4D scanner (3D + time) constitutes the core of our 4D center of expertise, in which the research groups Product Development, MOVANT, Vision Lab, EVECO and Op3Mech together with Center for Health and Technology (CHaT) have joined forces in a complementary collaboration with the aim to use dynamical models of the human body for the development of new products with improved comfort and functionality, to design fundamentally new products with important applications in health care, and to improve our understanding of the evolutionary history of the human body. The combination of academic and industrial expertise of Kinesiology with Product Development and virtual modeling and simulations makes the center unique in the world. The consortium will tackle open design problems with applications for mass customization (3D printing) and wearables.

Researcher(s)

• Promoter: Truijen Steven
• Co-promoter: Ribbens Bart
• Co-promoter: Saeys Wim
• Co-promoter: Sijbers Jan
• Co-promoter: Van Dongen Stefan
• Co-promoter: Verwulgen Stijn

Research team(s)

• Movement Antwerp (MOVANT)

Project type(s)

• Research Project

Abstract

The interaction between parasites and hosts is generally considered as one of the main driving forces in evolution. Evolution can occur if individual characteristics ("traits") are at least partly inherited, and are subject to natural selection. Therefore, to study the evolution of parasite traits, it is necessary to follow the success of individual parasites throughout their life-cycle. In many parasite species this is nearly impossible, except in highly artificial laboratory conditions. We will study the variation and heritability of parasite traits in ticks that are specialized on songbirds. We will breed ticks in the lab, and allow individual ticks to feed once per stage (larva, nymph or adult) on great tits taken from a wild population. In this way we will have information on the genetic relatedness of individual ticks as well as individual birds used in the study. This allows us to study to what extent variation in parasite success (feeding success, survival, number of eggs) is due to genetic variation in the parasite, or genetic variation in the host, or a combination of both. We will also study whether ticks that are highly successful on great tits do less well on other birds, and vice versa. Similarly we will study whether great tits vary in their ability to resist, or at least tolerate infestation by ticks, and whether birds that do better against one tick, are also successful against other tick species.

Researcher(s)

• Promoter: Matthysen Erik
• Co-promoter: Heylen Dieter
• Co-promoter: Van Dongen Stefan

Research team(s)

• Evolutionary ecology group (EVECO)

Project website

Project type(s)

• Research Project

Abstract

Developmental homeostasis (or developmental buffering) is a key factor in evolutionary process because it can maintain phenotypic consistency in spite of environmental and genetic variation and because it can hide cryptic genetic variation from selection. Despite a large interest, the basis of canalization and developmental stability (DS), the two main components of developmental buffering, are little understood. The aim of the project is to investigate the relationship between canalization and DS and to gain insights into their basis by studying their patterns of variation in different model species.

Researcher(s)

• Promoter: Van Dongen Stefan
• Co-promoter: Leirs Herwig
• Fellow: Breno Matteo

Research team(s)

• Evolutionary ecology group (EVECO)

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: Van Dongen Stefan
• Fellow: Iserbyt Arne

Research team(s)

• Evolutionary ecology group (EVECO)

Project type(s)

• Research Project

Abstract

Study of the reduction in developmental stability in plants exposed to different doses of radiation in Chernobyl.

Researcher(s)

• Promoter: Van Dongen Stefan

Research team(s)

• Evolutionary ecology group (EVECO)

Project type(s)

• Research Project

Abstract

Developmental instability (DI), the sensitivity of a developing system to random noise, is assumed to reflect quality and 'health' of populations and individuals. However, the literature is very heterogeneous and it is currently impossible to understand the reasons for this heterogeneity because of a lack of insights in the mechanisms that determine levels of DI. In this project we aim at gaining further insights in the mechanisms of DI.

Researcher(s)

• Promoter: Van Dongen Stefan
• Co-promoter: Bots Jessica

Research team(s)

• Evolutionary ecology group (EVECO)

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: Van Dongen Stefan
• Co-promoter: Leirs Herwig
• Fellow: Breno Matteo

Research team(s)

• Evolutionary ecology group (EVECO)

Project type(s)

• Research Project

Abstract

With this project we aim at disentangling the role of (recent) selection pressures and evolutionary response on the levels of DI and its sensitivity as a measure of stress and fitness. We will compare patterns between traits that are under stabilizing selection and under recent or more ancient directional selection.

Researcher(s)

• Promoter: Van Dongen Stefan

Research team(s)

• Evolutionary ecology group (EVECO)

Project type(s)

• Research Project

Abstract

With this project we aim at disentangling the role of (recent) selection pressures and evolutionary response on the levels of DI and its sensitivity as a measure of stress and fitness. We will compare patterns between traits that are under stabilizing selection and under recent or more ancient directional selection.

Researcher(s)

• Promoter: Van Dongen Stefan
• Co-promoter: Van Damme Raoul

Research team(s)

• Evolutionary ecology group (EVECO)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Van Dongen Stefan
• Fellow: Iserbyt Arne

Research team(s)

• Evolutionary ecology group (EVECO)

Project type(s)

• Research Project

Abstract

Developmental instability (DI), the sensitivity of a developing system to random noise, is assumed to reflect quality and 'health' of populations and individuals. However, the literature is very heterogeneous and it is currently impossible to understand the reasons for this heterogeneity because of a lack of insights in the mechanisms that determine levels of DI. In this project we aim at gaining further insights in the mechanisms of DI.

Researcher(s)

• Promoter: Van Dongen Stefan

Research team(s)

• Evolutionary ecology group (EVECO)

Project type(s)

• Research Project

Abstract

Species showing multiple morphs present a challenge for evolutionary theory. Current explanations for the evolution of female-limited polymorphism do not suffice to account for the recently observed variation in female morph frequencies, which is far greater than previously appreciated. Focus on variation in density and frequency in relation to morph-specific fitness, behaviour and morphology should allow reaching a more general explanation.

Researcher(s)

• Promoter: Van Dongen Stefan
• Fellow: Iserbyt Arne

Research team(s)

• Evolutionary ecology group (EVECO)

Project type(s)

• Research Project

Abstract

The genetic basis of developmental instability is only poorly understood. In this project, its evolutionary potential and genetic basis will be studies using classic quantitative genetic experiments, QTL mapping and micro-array analyses. Since developmental instability often increases with stress, we will determine its genetic and molecular architecture under different stress conditions.

Researcher(s)

• Promoter: Van Dongen Stefan
• Co-promoter: De Coen Wim

Research team(s)

• Evolutionary ecology group (EVECO)

Project type(s)

• Research Project

Abstract

Polymorphism is common in the natural world. In many damselfly species (Odonata) multiple female morphs are encountered in natural populations. Typically, two distinct morphs occur. While one female morph (called the andromorph) resembles the conspecific male in body colouration and sometimes behaviour, the other morph (called the gynomorph) is distinct. Recent studies suggest female polymorphism to be genetically determined and female morphs to face differential selective pressures. As such, it is widely believed that the polymorphism results from sexual conflict in which females have evolved traits to avoid excessive male harassment. The overall goal of my doctoral research is to come closer to understanding the maintenance and evolution of female-limited polymorphism. My main focus will be on evaluating the following questions: ¿Although a crucial assumption, evidence remains circumstantial on whether male harassment affects female fitness negatively, and does so differential with respect to female morph. This question will be studied experimentally by exposing female morphs to variable numbers of copulations and levels of male harassment while determining female morph longevity and fecundity. In addition levels of male harassment will be quantified in natural populations that differ in male densities and female morph frequencies. Also, I will evaluate whether female morph behaviour is variable under such different densities and frequencies. ¿Quantifying the spatial and temporal variation in female morph frequencies and male densities. This will be achieved through standardised sampling in natural populations using fixed transects or a uniform sample technique with an insect net. ¿Differences in body colouration and/or behaviour may have relevance for a species' thermal ecology, especially for ectothermic insects such as damselflies. Generally darker individuals heat up faster then paler ones which allows them to achieve a higher activity level (e.g. predator avoidance, egg maturation) under unfavourable weather condition, ultimately resulting in fitness advantages. Thus, I will study thermal characteristics of males and female colour morphs under laboratory conditions and in the field. ¿Several hypotheses suggest female morphs to vary in costs and benefits under different environmental conditions and assume female morph fitness to be variable. I will study variation in female morph condition (by determining several long-term and short-term signals) under varying environmental conditions (throughout an entire flight season). Different signals may indicate individual condition during different periods within an individual's lifetime. Body size and developmental stability (fluctuating asymmetry) reflects past (larval) history, whereas short-term signals depend on current nutritional status and are highly sensitive to changes in the environment.

Researcher(s)

• Promoter: Van Dongen Stefan
• Fellow: Bots Jessica

Research team(s)

• Evolutionary ecology group (EVECO)

Project type(s)

• Research Project

Abstract

Morphological development is affected by deterministic (environment and genotype) and stochastic (developmental stability and canalisation) components. The latter potentially relates to stress and may play an important role in evolutionary processes. In this project the effects of foodstress on developmental stability and canalisation will be studied using the skull of the multimammate rat (Mastomys natalensis) as model system. The genetic basis of the stochastic components will be investigated.

Researcher(s)

• Promoter: Van Dongen Stefan
• Co-promoter: Leirs Herwig

Research team(s)

• Evolutionary ecology group (EVECO)

Project type(s)

• Research Project

Abstract

Fluctuating asymmetry is a very promising yet controversial measure of fitness. In this project, its use will be tested in detail in zebra finches and great tits

Researcher(s)

• Promoter: Van Dongen Stefan
• Fellow: Baecke Xavier

Research team(s)

• Evolutionary ecology group (EVECO)

Project type(s)

• Research Project

Abstract

Fluctuating asymmetry (FA), i.e. small directionally random differences between the left and right side of a bilaterally symmetric trait, is a potentially interesting and useful indicator of various forms of stress. Although definitions may vary with different sources in the literature, the underlying developmental mechanism assumes that during growth, the developmental pathway of a trait is disturbed (by the processed named 'developmental noise') and that there may be mechanisms that attempt to limit the effects of these disturbances (the process of 'developmental stability'). The joint effect of noise and stability are known as developmental instability (Dl), where higher instability results in a, on average, higher degree of asymmetry. Many studies have shown or found indications that FA (and thus presumably Dl) increases with environmental (parasites, abiotic factors) and genetic (inbreeding, break-up of coadapted gene complexes) stress (reviewed in several chapters in Polak, 2003). Because it has been suggested that the effects of stress on FA may become apparent before important fitness consequences are observed, FA may act as an 'early warning system' (sensu Clarke, 1995) and may form an important tool to identify populations and/or species that require conservation measures before extintion is inevitable. Although of enormous potential in theory, the practical appliction of FA in general and in a conservation biology context more specifically, has been hampered by the vast heterogeneity in the observed associations between FA and stress. More specifically, the lack of general guidelines that allow to predict if and when - for which species(-groups), forms of stress and morphological traits -FA can be expected to increase with stress, has limited its use and has provoked may debates in the recent literature. This project aims at investigating the usefulness of FA as bio-marker of the potentially negative effects of inbreeding in two relatively closely related butterfly species (Pararge aegeria and Cymothoe teita). P. aegeria is a relatively common European butterfly while C. teita is a threatened and endemic species of the Taita Hills, Kenia. Both species inhabit woodlands that have become intensively affected by fragmentation and degradation worldwide. P. aegeria will be intensively studied under both controlled lab conditions and in the field. This part of the research will allow us to explore and test some fundamental aspects of factors that affect the F A-heterozygosity association ( details of specific hypotheses follow below). To achieve this, we will (i) perform a breeding experiment under controlled conditions where levels of inbreeding will be manipulated experimentally, (ii) study the FA-inbreeding association in the field, (iii) measure FA for a range of different traits that vary in functional importance and (iv) estimate genetic variation using markers with different levels of selective neutrality (microsatellite vs. allozymes, where for the latter butterflies have to be killed). This type of research can only be performed in species like P. aegeria which is relatively common and can be reared and manipulated easily in the lab. In research on threatened species, like C. teita, experimental possiblilities are limited and one should attempt to limit the impact of the research activities on the organism. Therefore, we will limit research on C. teita to measuring FA through digital fotographs and the estimation of genetic variation using microsatellite markers only, based on DNA amplified from small tissue samples. These two non-invasive and non-lethal methods will first be developed and tested in P. aegeria in the lab and field. The fundamental insights obtained from P. aegeria with respect to the FA-inbreeding associations will allow us to carefully plan the work on C. teita and to evaluate the observed patterns. In this project we specifically aim at addressing a number of fundamental questions w

Researcher(s)

• Promoter: Van Dongen Stefan

Research team(s)

• Evolutionary ecology group (EVECO)

Project type(s)

• Research Project

Abstract

Polymorphism is common in the natural world. In many damselfly species (Odonata) multiple female morphs are encountered in natural populations. Typically, two distinct morphs occur. While one female morph (called the andromorph) resembles the conspecific male in body colouration and sometimes behaviour, the other morph (called the gynomorph) is distinct. Recent studies suggest female polymorphism to be genetically determined and female morphs to face differential selective pressures. As such, it is widely believed that the polymorphism results from sexual conflict in which females have evolved traits to avoid excessive male harassment. The overall goal of my doctoral research is to come closer to understanding the maintenance and evolution of female-limited polymorphism. My main focus will be on evaluating the following questions: ¿Although a crucial assumption, evidence remains circumstantial on whether male harassment affects female fitness negatively, and does so differential with respect to female morph. This question will be studied experimentally by exposing female morphs to variable numbers of copulations and levels of male harassment while determining female morph longevity and fecundity. In addition levels of male harassment will be quantified in natural populations that differ in male densities and female morph frequencies. Also, I will evaluate whether female morph behaviour is variable under such different densities and frequencies. ¿Quantifying the spatial and temporal variation in female morph frequencies and male densities. This will be achieved through standardised sampling in natural populations using fixed transects or a uniform sample technique with an insect net. ¿Differences in body colouration and/or behaviour may have relevance for a species' thermal ecology, especially for ectothermic insects such as damselflies. Generally darker individuals heat up faster then paler ones which allows them to achieve a higher activity level (e.g. predator avoidance, egg maturation) under unfavourable weather condition, ultimately resulting in fitness advantages. Thus, I will study thermal characteristics of males and female colour morphs under laboratory conditions and in the field. ¿Several hypotheses suggest female morphs to vary in costs and benefits under different environmental conditions and assume female morph fitness to be variable. I will study variation in female morph condition (by determining several long-term and short-term signals) under varying environmental conditions (throughout an entire flight season). Different signals may indicate individual condition during different periods within an individual's lifetime. Body size and developmental stability (fluctuating asymmetry) reflects past (larval) history, whereas short-term signals depend on current nutritional status and are highly sensitive to changes in the environment.

Researcher(s)

• Promoter: Van Dongen Stefan
• Co-promoter: Van Gossum Hans
• Fellow: Bots Jessica

Research team(s)

• Evolutionary ecology group (EVECO)

Project type(s)

• Research Project

Abstract

Developmental stability is assumed to reflect individual genetic quality. Individual developmental stability can be estimated with seeming ease, by small deviations from perfect symmetry (i.e. fiuctuating asymmetry). In this project we study the effe cts of environmental stress on the presumed association between individual genetic quality and both developmental stability and fiuctuating asymmetry.

Researcher(s)

• Promoter: Van Dongen Stefan

Research team(s)

• Evolutionary ecology group (EVECO)

Project type(s)

• Research Project

Abstract

Developmental stability (DS i.e. the ability of an individual to buffer its development against random disturbances) is most often estimated by fluctuating asymmetry (FA i.e. small random deviations from perfect symmetry). The evolutionary potential of developmental stability has been the subject of much recent debate in the literature. There appears to be a high degree of heterogeneity in observed relationships between DS and fitness and in the heritabilities of FA and DS. One potential source that may explain this or part of this heterogeneity is the amount of environmental stress present in the different studies. In additions different traits and different kinds of stress may have varying effects. The aim of this project is to study the effects of different forms of environmental stress on the evolutionary potential of developmental stability of a variety of traits.

Researcher(s)

• Promoter: Matthysen Erik
• Fellow: Van Dongen Stefan

Research team(s)

Project type(s)

• Research Project

Abstract

Winter moth egg hatching is weakly synchronized with host budburst. This project aims at linking selectively neutral genetic markers to phenotype through artificial selection. After release of the reared individuals, the distribution of the genetic markers can be followed in space and the relative impact of natural selection and gene flow on the local adaptation process can be evaluated.

Researcher(s)

• Promoter: Van Dongen Stefan

Research team(s)

Project type(s)

• Research Project

Abstract

With mark-recapture experiments and poly-aerylamide gel electrophoresis will te effect of habitatframgentation on dispersal and colonization abilities and local adaptation be investigated.

Researcher(s)

• Promoter: Matthysen Erik
• Fellow: Van Dongen Stefan

Research team(s)

Project type(s)

• Research Project

Abstract

With mark-recapture experiments and poly-aerylamide gel electrophoresis will te effect of habitatframgentation on dispersal and colonization abilities and local adaptation be investigated.

Researcher(s)

• Promoter: Dhondt Andre
• Fellow: Van Dongen Stefan

Research team(s)

Project type(s)

• Research Project

Abstract

With mark-recapture experiments and poly-aerylamide gel electrophoresis will te effect of habitatframgentation on dispersal and colonization abilities and local adaptation be investigated.

Researcher(s)

• Promoter: Dhondt Andre
• Fellow: Van Dongen Stefan

Research team(s)

Project type(s)

• Research Project