Institute of Evolutionary Biology and Environmental Studies

Suggestions for Master's projects

Animal Behaviour
Ecology and Environment
Evolutionary Biology

Animal Behaviour

How to find a cooperative partner

Wild female house mice sometime cooperate to rear litters of pups. Partner choice is important, as lab studies have shown that a poor match can result in reproductive failure. How do females choose social partners for cooperative maternal care? Do they choose based on familiarity, genetic relatedness, extent of previous association, physical characteristics, or other characters? How much does partner choice influence reproductive success in a wild population?
In this project relevant data will be collected from a wild house mouse population near Zürich that is intensively monitored. Using the collected data, as well as data already available, the effect of the above factors on communal nursing partner choice will be assessed. An experiment will then be designed to test in the laboratory the factors which are found to have the largest effect on wild mouse female social partner choice.

Contact:
Dr. Anna Lindholm
Prof. Barbara König

Genetics and social behaviour of wild house mice

In Switzerland, house mice populations differ in the number of chromosomes, from 22 to 40. When mice with different numbers of chromosomes mate, then inviable offspring are likely to result. Two consequences are that females should have a mate preference for males which will give them viable offspring, and gene flow between populations of different chromosome numbers should be restricted.
This leads to a number of questions. How does a male’s chromosome number influence female mating preference? How does female reproductive success vary with the compatibility of her and her mate’s number of chromosomes? Can this explain the extent of genetic differentiation between house mouse populations?
In this project, wild mouse from populations near Zurich will be captured, brought to the lab, karyotyped, and genotyped. Mating crosses will be carried out, and female preferences will be tested using a sophisticated choice test apparatus. Population differentiation at neutral microsatellite markers will be assessed, and related to the outcome of mating crosses, and female preference tests.

Contact:
Dr. Anna Lindholm
Prof. Barbara König

Bird song as a signal of male quality

Bird song is thought to signal male quality, both to potential female mates and to male competitors. But it remains unclear what the genetic basis of male quality is and how its variation is maintained. In this project we will first test which song properties are good indicators of male quality. Subsequently, we will test whether only a few genes are important, or whether there are so many genes involved that a good signal of male quality reflects genome-wide heterozygosity. Further research may investigate the role of song and genetic variation in mate choice.
Together with Prof. Dr. Lukas Keller and Dr. Erik Postma, we are studying these and other questions in a small population of song sparrows (Melospiza melodia) on Mandarte Island, British Columbia, Canada. We combine data from a deep pedigree, 230 microsatellite markers and a suite of ecological, behavioral and morphological traits collected over almost three decades. This Master’s project includes two to four months of fieldwork on Mandarte Island in early spring 2012, followed by molecular work in the laboratory and statistical analyses of the song and genetic data. Please feel free to contact Pirmin Nietlisbach for further information or to indicate your interest in the project.

Contact:
Pirmin Nietlisbach

Automated observation of behaviour

Quantitative measures of the behaviour of many individual organisms over long durations can be very labour intensive, often prohibitively so. Yet such measurements can be the foundation of understanding how organisms interact with their environment, with each other, and how they respond to changing environmental conditions. The project will involve development and testing of a system for automating the process of observing and quantifying the behavioural characteristics of many individuals of different species simultaneously. Small aquatic organisms will be the model system used for development. The project will be of most interest to students with a strong interest in technical development, computational analyses, and organismal biology.

Contact:
Prof. Owen Petchey

Ecology and Environment

Connecting fragmented habitat for biodiversity conservation

Tropical forests are reknown for their wealth in biodiversity and their ongoing degradation leads to a subsequent loss of species. The Rhino and Forest Fund (RFF) supports the restoration of tropical forest to increase the carrying capacity of endangered species, such as the Bornean rhino (Dicerorhinus sumatrensis harrissoni). After initiating a pilot project in 2011, the RFF now plans to extend the efforts to connect fragmented habitat with wildlife corridors.
For this master project we search for a student that is interested to work at the interface between fundamental research and conservation. The task is to develop a management plan that determines which measures of habitat restoration are most effective. The candidate will perform a population viability analysis and combine home range data of the Borneo rhino with ArcGIS maps of degraded forest areas and palm oil plantations.
The candidate will determine areas of potential habitat restoration by working in the field, but also by analyzing existing data (home range data) collected by others. The study site is the Tabin Wildlife Reserve in North Borneo (Malaysia). The candidate should therefore be prepared to live under remote field conditions in a tropical rainforest (camping in the rainforest or in basic housing). Data collection will include a tree vegetation survey for the later mapping and the set-up and maintenance of camera traps.

Company:

Workplace:
Institute of Environmental Biology and Environmental Sciences, University of Zürich

Education:
We are looking for a master student that already has experiences of working in remote conditions. Ideally the candidate has worked on a species conservation project or has similar experiences. The candidate should be driven by strong self motivation and is expected to develop some of the work independently.

Entrance:
Autumn 2011

Remarks:
For further information, please contact Philippe Saner Dr. Philippe Saner
Supervisors:

Arctic tundra vegetation in a changing climate – observing vegetation from space

The Arctic is one of the regions on earth most affected by temperature increase related to climate change. We contribute to an international research group (Russian, Dutch, Japanese, Swiss) working in the Kytalyk nature reserve, close to Chokurdah, in NE Siberia. Our aim is to assess vegetation changes and related feedbacks (energy and carbon cycle) to the climate system using a combination of ecological experiments, dendrochronology, and remote sensing methods.
A wealth of data is available, also fresh data from this summer field campaign, to address different questions in your Master thesis. Examples are linking dendrochronological records with satellite data, spectral fingerprinting of tundra vegetation based on field spectrometer data, analysing landscape albedo variability in the Arctic, or mapping potential Siberian crane habitat. Depending on the research focus, you might collaborate with one of the international partners and contribute to a planned peer-reviewed publication.

Contact:
Dr. Gabriela Schaepman-Strub

Land use and vegetation change assessment in Grindelwald

The NSF project "Analyzing and Modeling Transitions of Common Property Pastures in the Swiss Alps" (PI Prof. Claudia Binder) is looking for an MSc student who is interested in land-use and vegetation-change assessments.

Background of the project: The main goal of the NSF project is to analyze and assess the role of local governance systems for the development of ecological and social systems in the Swiss Alps over time. We characterize, analyze, and model transitions in the management system of common property pastures in the Swiss Alps, with special focus on institutional development, land-use change and biodiversity.

Objectives for the MSc study: Based on former vegetation and land-use assessments (1980-1982), related land-use change scenarios, and the analysis of potential driving factors of land-use change, a sample of about 600 out of the originally more than 5000 plots shall be re-assessed (botanical composition, succession models, general statistics). The plots will be selected to represent different levels of the factors which are most likely driving the change. For each of the 600 plots the state it was in in 1981 and in 2012 will be determined. This will allow us to calculate transition probabilities between states and relate these probabilities to the driving factors. This work shall lead into scenarios on potential transitions of the ecological system in the future.

Requirements:

Supervision:

Contact:
Prof. Bernhard Schmid

Reconstructing the past climate of Aldabra, a coral atoll in the Indian Ocean

In this project you will learn how past climate can be reconstructed using tree rings. Aldabra is a World Heritage Site and is dominated by the world's largest population of giant tortoises. The climate is seasonal with a single wet season which is followed by a long dry season, in which many of the trees and shrubs on the island drop their leaves. This should lead to the formation of clear tree rings, where the width of the ring indicates the length of the growing season. You will analyse tree cores taken from the island, determine the age of the trees and look for links between ring width and climate using the local meteorological records that are available for the last 50 years. If good correlations exist and trees are old enough, then we can also extrapolate beyond 50 years to find out if and how the climate of Aldabra has changed. This project might form the basis of a future PhD on vegetation and climate on Aldabra.

Contact:
Dr. Lindsay Turnbull
Dr. Gabriela Schaepman-Strub
In conjunction with David Frank of the WSL, Birmensdorf

Constructing food webs using bees and their parasites from city gardens

This project allows you to construct and analyse food webs and relate them to environmental variables. Last year, Sarah Pellkofer put out trap nests in 32 gardens around the city of Zurich. The gardens varied in their size, use of pesticides and degree of urbaneness. These trap nests have been brought in, but the bees need time to emerge and be identified. In addition, bees suffer from parasitic species that will emerge instead! Your project involves identifying and classifying the emerging insects so that food webs for each garden can be constructed and analysed. This will give essential information about how food webs are affected by the urban environment. The project also includes geospatial analysis for determining landscape features of the gardens. There is also scope for the person to carry out an additional experiment on pollination or insect diversity during the summer.

Contact:
Dr. Lindsay Turnbull
Dr. Gabriela Schaepman-Strub
Sarah Pellkofer

Aeromicrobiology—Occurrence, distribution and biodiversity of air-borne microbes

Determination of bacterial and fungal bioaerosols at selected indoor or outdoor locations.

Bioaerosols are defined as aerosols (solid or liquid particles in a gas) of biological origin. These include viruses, viable organisms such as bacteria and fungi as well as products of organisms such as bacterial or fungal spores, plant parts or pollen. Composition and concentrations of microbes in the bioaerosol vary with the source and the dispersal in the air until deposition. Possible sources comprise fresh and marine surface waters, soils, plants, and animals. Usually, particle concentrations show large variations depending on sampling locations. In addition, seasonal as well as diurnal fluctuations occur. Airborne particles as well as bioaerosols can easily be counted and analyzed by suited equipment without the need of complicated subsequent analytical techniques to study size distribution and biodiversity.

Contact:
PD Dr. Helmut Brandl

Geomicrobiology—mineral solubilization

Mobilization of metals from solid minerals and solid wastes by microorganisms (e.g. acidophilic bacteria, fungi, HCN-forming microbes)

A microbial mobilization process ("bioleaching") will be applied for the biological solubilization solid materials such as rocks, minerals, or ores as well as solids wastes such incineration residues, galvanic sludge, foundry sands, or electronic scrap. The solubilization is mediated by microbial acid formation, reduction/oxidation processes or the excretion of specific metabolites. As example, hydrocyanic acid (HCN) is formed by a variety of bacteria and fungi. In the presence of cyanide nearly all transitions metals (except lanthanides and actinides) form well-defined complexes which show often a very good water solubility and are characterized by a high chemical stability. By combining these chemical and microbiological principles, basic research will be performed to develop a process for the solubilization of metals from metal-containing solid materials as water-soluble cyanide complexes.

Contact:
PD Dr. Helmut Brandl

Geomicrobiology—microbial life in gradients

Physiological studies of microorganisms under varying environmental conditions (in nutrient gradients) affecting influence on microbial metabolism (e.g. on HCN formation)

Microorganisms are able to grow under a wide range of environmental conditions, e.g. even at extremely low pH values, at very high temperatures, or in the presence of toxic metals. Although certain microbial strains find their optimal growth conditions under these circumstances, many microorganisms are stressed by these factors resulting in reduced growth or other physiological reactions (e.g. spore formation). Understanding of the influence of environmental parameters on microbial growth and survival offers insight into the activities and distribution of microorganisms in nature, especially when polluted habitats are considered. A two-dimensional cultivation technique will be developed to map the response of an organism in relation to two stress parameters varied simultaneously. Briefly, growth of microbes will be studied in relation to gradients of different stress parameters (e.g. salinity, metal concentration).

Contact:
PD Dr. Helmut Brandl

Plant-Microbe-Interactions—antibacterial effects of plant extracts

Influence of extracted plant metabolites (e.g. esculin) on microorganisms using lab techniques such TLC overlay and Degramat

Bioautography is a screening and the most important detection method for new or unidentified antimicrobial compounds. It is based on the biological activity of the analyte, which can be antibacterial or antifungal. It is used following thin layer chromatography (TLC) and is divided into agar diffusion or contact bioautography, immersion or agar-overlay bioautography and direct bioautography . In our case, we will direct bioautography, spraying a malt extract solution with fungal spores onto the TLC plates. After incubation of the fungal spores it is possible to see inhibition zones on the silica plate.

Contact:
PD Dr. Helmut Brandl

Plant-Microbe-Interactions—effect of microorganisms on plant growth

Influence of water-soluble and gaseous metabolites of plant growth (studied e.g. in sectioned Petri dishes or gas chambers)

The rizosphere of plants is the location of intense interactions between plants and a diverse soil microbial community including amoeba, ciliates, fungi, bacteria, and viruses. All “players” in this community affect each other, both positively and negatively These effects are mainly based on chemical compounds secreted by the plants and the microorganisms and include a wide range and a very complex mixture of water soluble compounds, e.g. carbohydrates, fatty acids, or alcohols as well as gaseous, volatile metabolites including alcohols, acids, aldehydes, esters, sulphur compounds. Regarding their generation by bacteria however, volatiles (volatile organic compounds, VOCs) have been largely neglected in experimental assays and only recently investigation on stimulating or inhibiting effects on plants and fungi are performed in more. Experimentally, the approach to study these interactions is quite simple: Cocultivation of rhizobacteria with fungi or plants in segmented (di- or tripartite) Petri dishes have been used to determine microbe-plant/fungi-interactions. One sector or segment of the Petri dish is filled with an agar medium supporting bacterial growth, whereas plant seedlings or fungi were placed in the second compartment with their respective media.

Contact:
PD Dr. Helmut Brandl

Instrumental Ecology—FTIR microspectroscopy

Application of infrared spectroscopy in ecology for the differentiation of plants (trees, wood, grasses), additionally, e.g. bacteria, fungi, pollen; mycorrhiza; biofilms; volatiles

Although Fourier transform infrared spectroscopy (FTIR) is routinely used as analytical tool in chemistry since many years, this technique is very rarely applied in ecology. An infrared spectrum of a sample represents a fingerprint with absorption peaks corresponding to vibrations between the chemical bonds of the atoms making up the material. Because each different material is a unique combination of atoms, no two compounds produce the exact same infrared spectrum. Therefore, infrared spectroscopy can result in a positive identification of every different kind of material.

Contact:
PD Dr. Helmut Brandl

Environmental consequences of nitrogen deposition: the role of mycorrhizal fungi

Nitrogen (N) inputs to ecosystems have increased worldwide, often leading to large changes in plant community structure and reducing plant species diversity. Yet, the interaction of increased N availability with other factors that determine plant community composition, are still poorly understood. In this project you will test whether the impact of N addition on plant communities depends on the presence of arbuscular mycorrhizal fungi (AMF). AMF are widespread plant symbionts that facilitate growth of many plant species. In this project you will establish diverse grassland microcosms with high and low N availability and you will manipulate the presence and diversity of AMF in these microcosms. It is hypothesized that diverse AMF communities reduce the negative impact of N addition on plant communities by supporting growth of species that are sensitive to N enrichment.

References:

Contact:
Prof. Marcel van der Heijden, Forschungsanstalt Agroscope Reckenholz-Tänikon ART, 044 377 72 78

Invasive alien species: past experience and future management

Plants and animals imported from afar are transforming ecosystems, while causing human problems as well as human benefits. These aliens are purportedly the second largest source of biodiversity loss after habitat disruption. Moreover, recent imports (such as Solidago) are exacerbating human allergies, facilitating the spread of disease (as in the case of Aedes albopictus), or increasing wildfires (e.g., through Poa pratensis) so that there is great need to understand these impacts and learn how to manage them. While ecologists are studying the biological relationships of these organisms, there remain surprisingly few studies that address political, sociological, and historical effects of these creatures. This project therefore focuses on these social issues by as by consulting experts or other interest groups, searching through natural resource archives, or doing field work. Collaboration with other group leaders and other institutes is encouraged. The research questions about alien species can be categorized into purposely and accidentally imported species, and might dwell on any of the following questions:

Contact:
PD Dr. Marc Hall

Maledetta malaria: Linking ecosystems and human health

Ecohealth experts (or disease ecologists) call attention to the ways that polluted and transformed ecosystems can adversely affect human health. This project explores the relationships between healthy ecosystems and healthy bodies by focusing on the methods of combating malaria, the world's second most deadly killer. Draining wetlands and spraying pesticides (such as DDT) kill malaria's mosquito vector, but these activities also alter food webs, modify biodiversity, and threaten human physiology. This project focuses on the Swiss experience with malaria during the early 20th century, to explore how efforts of combating this disease transformed ecosystems. The site location is the Mogadino Plain, Ticino. Sources of information include health experts and ecologists, as well as records found in local archives and libraries, including the Swiss Tropical Institute, Basel. Questions might include:

Contact:
PD Dr. Marc Hall

Restoration challenges: Identifying appropriate target states for re-naturing projects

The project focuses on finding better ways to restore damaged natural systems. In particular, land managers who set out to rehabilitate degraded lands or reintroduce endangered species must offer a rationale for choosing the target conditions they intend to bring back. The enormous variation of biota in similar habitats means that restorationists cannot often rely on archival and paleoecological methods to reveal pre-degraded, more natural systems. They may therefore need to rely on non-historical rationales for justifying restoration's target conditions. Such target conditions may be identified through public surveys, through locating and describing acceptable reference states, or through predictive analyses of what ecosystems would look like if left undisturbed. A relevant field site and current restoration project will be studied, within Switzerland or beyond. Key questions might include:

Contact:
PD Dr. Marc Hall

Ecohealth: Changing visions of alpine health

How have mountains come to be seen as healthy places, abundant with clean, fresh air, invigorating sunlight, and soothing mineral waters? Two centuries ago, residents of the Alps were some of Europe's most undernourished, disease-riddled people facing a hard life in a brutal land, and were hardly a picture of glowing health. Only around 150 years ago did this image begin to change as alpine clubs and outdoor enthusiasts trumpet the glories of the high mountains. This research will endeavor to trace at least part of this shift from Alpine-hell to Alpine-spa. While Marjorie Hope Nicolson emphasizes the growing celebration of alpine nature in her classic Mountain Gloom, Mountain Glory (1959), by illustrating the new glory of God seen through high mountains, she hardly mentions changing notions of mountain health. This project might concentrate on a handful of famous mountain spas, for example, to explore how these establishments became meccas for the sickly and arthritic searching for cures -- all while residents living near such spas traditionally reflected dismal health, sporting goiters and other deformities, suffering respiratory illnesses, sunburned skin, nutritional deficiencies, and worse. Important questions include:

Contact:
PD Dr. Marc Hall

How does fertilization threaten grassland plant diversity?

Fertilization is threatening grassland plant biodiversity worldwide. The Master involved in this project will contribute to an international research cooperation covering 10 countries on 4 continents (Nutrient Network) working in the Swiss site (Zuggerberg). The aim of the project is to assess the changes in plant communities and to understand the mechanisms leading to the loss of plant diversity with fertilization.

The Master will have access to four years of data collection and will participate to the collection of important new information. Using a combination of ecological experiments and analytical tools, the Master will address different questions examining the impacts of environmental change on grassland communities and ecosystems. Depending on your interest and involvement, you might collaborate with international partners and contribute to a planned peer-reviewed publication.

Contact:
Dr. Yann Hautier
Prof. Andy Hector

Food webs, foraging behaviour, and allometric scaling

Food webs, foraging behaviour, and allometric scaling are coming together to create a new and exciting frontier of research in ecology. This frontier aims to help understand the forces that structure ecological communities, and to provide an empirically evidenced theoretical foundation for predicting effects of environmental change on ecological communities. Relevant environmental changes include extinctions, invasions, temperature fluctuations, and habitat loss. The project will involve researching any of several new ideas in this field, and will suit students with a strong interest in coupling empirical data with theoretical models, and students that have the ability to think broadly and imaginatively while still focusing on a specific research question.

Contact:
Prof. Owen Petchey
Interested students could start by reading an article in Functional Ecology

What determines how fast I eat? Biotic and abiotic influences on feeding rates of aquatic organisms

Understanding how fast organisms eat is key for understanding the dynamics of predator-prey interactions. All sorts of factors can affect feeding rate, and during this project you will conceive, design, perform, and analyse experiments with small predators in lab-based communities. These predators are, despite their small size, quite impressive and voracious consumers! Which factors are investigated, such as prey identity, temperature, and disease, will be decided in collaboration with Owen. Depending on your interests, the project could include modelling of the dynamic consequences of your findings.

Contact:
Prof. Owen Petchey
For an example of the kinds of results and conclusions that a similar study found, take a look at this paper

Body size and extinction risk… is there a general pattern?

There seems to be lots of evidence that species with large bodied individuals experience greater risk of extinction than ones with small individuals. There are many reasons why one would expect this to be the case. But there are also many examples of no relationship between size and extinction risk. This project will compile data about relationships between body size, extinction risk, and other pertinent variables. This data will come from previously published studies. New analyses of the compiled data will be used to discover how general is the relationship between size and extinction risk, and to, where possible, to disentangle mechanisms by which body size influences extinction risk.

Contact:
Prof. Owen Petchey

Coral reef fish functional diversity

Biodiversity is thought be strongly influenced by environmental factors, such as habitat structural complexity. Therefore changes in habitat complexity, perhaps caused by the activity of humans, could lead to changes in biodiversity. To a large extent, these effects depend on the dominant processes by which communities assemble. This project will aim to disentangle the processes by which communities of coral reef fish assemble, and link these findings with relationships between coral (habitat) structural complexity and reef fish diversity. The project will involve analyses of a large existing dataset of coral reef fish communities and compilation of a dataset about the functional traits of the fish species.

Contact:
Prof. Owen Petchey

Evolutionary Biology

Hybridization in Mediterranean Pipefish

Interspecific hybridization is thought to play an important role in adaptive evolution. The offspring of successful matings between closely-related species often exhibit trait mosaics, and instances of transgressive segregation may allow hybrid offspring to capitalize on novel resources. Hybridization has occurred repeatedly during the evolutionary history of Mediterranean pipefishes, and contemporary hybridization continues to influence the pattern of diversification and divergence in this group. This project will quantify the frequency of natural hybridization between species of known hybrid ancestry with the aid of molecular-based parentage analyses, investigate congeneric mate preferences using lab-based mating experiments, and evaluate the effects of interspecific matings on traits of adaptive significance, in an effort to quantify the evolutionary significance of contemporary hybridization in this system.

Contact:
Prof. Tony Wilson

Prolactin and Male Pregnancy in the Seahorse

Pituitary Prolactin (PRL) is one of the chief hormones regulating mammalian reproduction. This hormone is also implicated in male pregnancy in seahorses and pipefish, a group of marine fishes in which males provide all post-fertilization parental care. The key role of this hormone in what are clearly independently-derived reproductive systems raises important questions on the evolution of reproductive complexity, and whether the hormone is functionally equivalent in these two forms of reproduction. This project aims to characterize the expression pattern of prolactin and its receptor during male pregnancy in the seahorse (Hippocampus abdominalis), determining how tissue-specific changes in the expression patterns of these two compounds influence morphological and physiological modifications associated with male pregnancy in this species.

Contact:
Prof. Tony Wilson

Post-glacial Colonization and Niche Conservativism in Marine Systems

Latitudinal gradients in species diversity are ubiquitous, but explanations for such gradients remain elusive. The fact that both intraspecific and interspecific diversity are often reduced at higher latitudes suggests that such latitudinal gradients are strongly influenced by historical recolonization, but spatial differences in resource availability may ultimately limit community size across environments. Syngnathus pipefish are dominant members of the nearshore environment along the European coastline, and these species show a clear signature of post-glacial recolonization, with reduced intra- and interspecific diversity at higher latitudes. Dietary differences among regions are associated with striking trophic variation, suggesting that resource availability may determine species range limits in this group. This project aims to quantify food availability and dietary preferences of pipefish populations along this gradient in order to assess whether resource availability limits the recolonization of northern habitats, or if successful colonizers can capitalize on a wider range of resources in the absence of direct competitors.

Contact:
Prof. Tony Wilson

Size- and nutrient dependent time-budgets and pairing success of yellow dung fly males in the field

Animals have to trade off their daily time and their energy reserves between foraging and mating activities. This trade-off likely depends on body size. Yellow dung fly males spend most of their time around dung pats waiting for females to mate with, as this is how they can best maximize their reproductive success. However, individuals have to forage some time for nectar (their energy source) and prey (their source of protein), for which they have to leave the pasture. Small males lose in direct mate competition against larger males, but they could increase their mating success by spending more time at the mating site. The latter is possible if small males need less food and/or if they spend less energy per unit time or body mass. By marking and tracking field males that have been fed different diets, this project assesses the size-dependent time (and energy) budgets of yellow dung flies to find possible physiological advantages of small body size.

Contact:
Prof. Wolf Blanckenhorn

Size-dependent predation on yellow dung and black scavenger flies examined in a laboratory setting

Fitness advantages of large body size are plentiful whereas disadvantages are rarely seen. Size-dependent predation by particular predators on particular prey species should be common in the animal world. Predators might prefer larger prey because of higher energy returns, or they may prefer smaller prey because of gape limitations. From the standpoint of any particular prey species, which faces various predators, net viability selection will depend on the size-preferences of their different predators. We investigate individual predators’ (frogs, insects, salamanders, lizards, etc.) size-preferences when preying on two species of common dung flies of different sizes in the laboratory at semi-natural settings, ultimately with the goal to document possible predation advantages of small flies.

Contact:
Prof. Wolf Blanckenhorn

Temperature sensitivity in latitudinal yellow dung fly populations

The response of animals to thermal extremes may be associated with fitness benefits or costs resulting e.g. from an increase in the expression of stress proteins such as heat shock proteins HSP. We investigate systematic variation in thermal tolerance and fitness-related traits in the yellow dung fly across a latitudinal gradient ranging from Sweden to Spain by measuring temperature- and size-dependent reproductive success of females and males under semi-natural conditions in the laboratory.

Contact:
Prof. Wolf Blanckenhorn

The genetic basis underlying genital variation in Drosophila melanogaster

Animal genitalia evolve extremely fast such that species diversity is almost inevitably bound to the diversity in reproductive organs. Contrary to studies of the evolutionary forces affecting variation in genital morphology, current knowledge of the genetic basis underlying this variation is still very limited despite its importance for understanding the process. In this project we want to localize quantitative trait loci (QTL) affecting variation in the posterior lobe of the genital arch in Drosophila melanogaster. Previous QTL analyses of hybrid crosses not only indicated a highly polygenic basis, but also that species differences in the size and shape of the genital arch are likely due to episodes of strong directional selection in the evolutionary past. Our QTL approach will thus provide complementary information on the genetic architecture underlying genital diversification before reproductive isolation mechanisms evolve.

Contact:
Dr. Martin Schäfer
Prof. Wolf Blanckenhorn

Comparative reproductive behavior, life history and morphology of various Sepsidae

Males have a limited amount of resources to invest in reproduction. This suggests a rich evolutionary interplay between traits that enhance mating success and those enhancing fertilization success, the outcome of which is expected to vary strongly with the mating system. By using phylogenic, population genetic and experimental approaches, we investigate in an integrative manner how mechanisms of pre- and post-copulatory sexual selection interact and contribute to the divergence in sexual size dimorphism, genital and secondary sexual trait morphology, and mating behavior among species and populations of Sepsid flies (Diptera: Sepsidae). Three related projects can be offered. The first project targets the role of pre- and post-mating sexual selection acting on various genital and body traits in several closely related sepsid species. The second, common garden project addresses the phenotypic plasticity and heritability and hence the evolvability of the studied traits and their scaling relationships in the same species. The third project is a population genetic approach that compares quantitative genetic variation relative to that of neutral genetic markers using multiple populations of two species showing contrasting patterns of sexual size dimorphism.

Contact:
Prof. Wolf Blanckenhorn
Dr. Martin Schäfer

The role of surface pheromones for sexual selection in Sepsid flies

Sepsid flies show a high diversity in body sizes, sexual size dimorphism, mating system and mating behavior. Sexual selection on body size obviously contributes to the evolution of body size and dimorphism, but will highly depend on the mating system. We study sexual and fecundity selection on body size in various sepsid species. However, behavioral traits such as courtship or short-distance and surface pheromones likely play an equally important role for male mating success as body size. We investigate the role of surface proteins (phereomones) in sexual selection in various sepsid species using gas chromatography and mass spectroscopy (in collaboration with Dr. Florian Schiestl, Institute of Systematic Botany).

Contact:
Prof. Wolf Blanckenhorn
Florian Schiestl, Institute of Systematic Botany

Ecophysiology of maternal yolk hormones in birds

The environment an animal encounters before its birth has important consequences for its later life. In my group, we investigate why mothers differ in their investment into their unborn young, what the genetic basis of this maternal investment is and how environmental factors influence it. In birds, an important component of this prenatal environment are yolk hormones that mothers transfer to the egg during synthesis.
In this project, you will analyse the hormone content of songbird eggs that have been collected during several years. Because of an existing database, this will allow you to test statistically for the consequences of prenatal maternal hormone transfer on offspring performance. Information on egg composition between relatives will furthermore allow you to estimate the heritability of yolk hormone transfer.
In addition, more field-based MSc projects are also available within this project. Contact me for more information.

Contact:
Prof. Barbara Tschirren

I like him too! – Heritability of partner preference in Japanese quails

Evolutionary theory predicts that sexual selection will lead to a genetic correlation between male sexual attractiveness and female preference. Whereas numerous studies have investigated the genetics of male attractiveness, it is largely unknown if female mate preference and mate choosiness have a genetic basis. This projects aims at filling this gap. Using Japanese quails, you will perform mate choice tests with genetic sisters and half-sisters. You will identify statistically what makes a quail male attractive to females and if the preference and choosiness of sisters is more similar than expected by chance (i.e. if it is heritable).

Contact:
Prof. Barbara Tschirren

Borrelia prevalence in natural rodent populations across altitudinal gradients in the Swiss Alps

Lyme borreliosis is the most common zoonotic disease in Europe and North America. It is caused by members of the Borrelia burgdorferi sensu lato bacteria complex, which are transmitted by ticks to a wide range of vertebrate hosts, in particular small rodents. In this study, you will assess the reservoir potential of different free-living rodent species and measure clines in Borrelia prevalence across altitudinal gradients in the Swiss Alps. It has been suggested that due to climate change Borrelia now occurs at higher altitudes and thus affects populations that were previously Borrelia-free. This makes Borrelia an ideal model to study the consequences of newly emerging diseases on host evolution and life history.
The project requires substantial amount of fieldwork under sometimes difficult conditions (terrain, weather) for several weeks, during which you will catch rodents along altitudinal gradients. Back in the lab, you will use molecular methods to detect Borrelia infections. Using statistical methods, you will learn how to compare the reservoir potential of different rodent species and to quantify altitudinal clines in Borrelia prevalence.

Contact:
Prof. Barbara Tschirren

Parasite-mediated selection on candidate immune genes along altitudinal gradients in the Swiss Alps

Understanding why individual hosts as well as host populations differ in their resistance to parasites, and how this affects the evolution of parasite virulence and host life history are fundamental quests in the field of evolutionary ecology. At the same time, it can provide an evolutionary framework for the applied management of human and wildlife diseases.
In this project you will study patterns of parasite-mediated selection acting on candidate genes for parasite-resistance in free-living rodents along an altitudinal gradient in the Swiss Alps. The project requires substantial amount of fieldwork under sometimes difficult conditions (terrain, weather) for several weeks, during which you will catch rodents along altitudinal gradients. Back in the lab, you will use molecular methods for genetic sequencing of candidate genes as well as neutral genetic markers. Using statistical methods, you will learn how to detect selection acting on genes, if this selection differs along altitudinal gradients, and if patterns of selection differ between immune genes and neutral markers.

Contact:
Prof. Barbara Tschirren

Ecology of Oral Pathogens

Filamentous bacteria are ubiquitous in aquatic and terrestrial environments. Moreover, they can be multicellular, hence they are suitable case studies for the evolution of multicellularity. A recent work of Rossetti et al. (Journal of the Royal Society Interface, (2011) 8, 1772-1784) studied the ecological conditions for the emergence of multicellular life cycles in filamentous, multicellular bacteria.

Filamentous bacteria are also relevant pathogens of the animal and human oral cavity. By extending the validation of the results obtained in Rossetti et al to pathogenic species of the oral cavity, the project aims to assess the presence of a cyclic pattern of the filament length, and the conditions for the emergence of multicellular life cycles. Besides the importance in the study of the evolution of multicellularity, the obtained results are expected to provide new insights into the ecology of oral microbes and to be potentially applied to the study of their pathogenicity.

Contact:
Prof. Homayoun Bagheri
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Environmental variation and the rate of evolution

Environmental variables, such as temperature, fluctuate through time, and these fluctuations can have different temporal patterns of variation in different habitats. These fluctuations affect organisms and have consequences for populations and communities, such as affecting the abundances of populations. An open question is, however, how temporal fluctuations affect the course of evolution. Does evolution happen faster in more or less variable environments? Does evolution proceed more quickly in warmer environments, simple due to decreased generation times? The project will involve experimental evolution of laboratory populations of E. coli, coupled with molecular analyses to examine evolutionary change.

Contact:
Prof. Owen Petchey

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