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Seminar WS 2021/22

Studenten, die am Seminar teilnehmen (nur online), können dies als Wahlfach anerkannt bekommen  (KV 128 804 “Ausgewählte Themen der Wildtierökologie”)

Due to the ongoing COVID19 pandemic all seminars will continue to be held online.
To participate please apply for a link to the video conference by sending a request by email

Wegen der COVID19 Pandemie finden alle Seminare bis auf weiteres online statt.
Um an der Video Konferenz teilzunehmen schicken Sie bitte ein email, wir schicken Ihnen dann den Link zu.

Seminarprogramm

In most species males tend to compete for access to females, and females often prefer certain males. That’s sexual selection for you. But what factors make a male more successful than the average? Using recent studies on mosquitofish from researchers in my lab we will investigate long-standing claims that: (a) older males are less attractive (not that I have a vested interest in the answer!); (b) that winners keep on winning; and (c) that heavy investment into sperm production reduces the future attractiveness of a male. We will then take a bigger picture view and describe some recent work by a colleague and I that tests the claim that stronger sexual selection on males promotes greater variability among males than females. You might know this from widespread media claims that men are more likely than women to be a genius or an idiot. But is the same true in other animals? 

Humans have brought about unprecedented changes to environments worldwide. For many species, behavioural adjustments represent the first response to altered conditions.  Such behavioural modifications can potentially improve an organism’s prospects of surviving and reproducing in a rapidly changing world. However, not all behavioural responses are beneficial. Human-altered conditions, for instance, can undermine the reliability of sexual signals used by animals to assess potential suitors. Environmental changes can also impair sensory systems or interfere with physiological processes needed to mount an appropriate behavioural response. An understanding of behaviour could therefore be important in helping to explain why some species are able to survive, or even flourish, under human altered conditions, while others flounder. In this talk, I will consider the pivotal role that behaviour plays in determining the fate of species under human-induced environmental change, and discuss recent research in my Group investigating the impacts of anthropogenic change on behaviour in fish.

Humans routinely confront situations that require coordination between individuals, from mundane activities such as planning where to go for dinner to incredibly complicated activities, such as international agreements.  How did this ability arise, and what prevents success in those situations in which it breaks down? To understand how this capability has evolved, my lab has used the methodology of experimental economics in order to address these questions in a cross-species fashion.  Experimental economics is an ideal mechanism for this approach, as it is a well-developed methodology for distilling complex decision-making in to a series of simple decision choices, allowing these decisions to be compared across species and contexts. We have used this approach to investigate decisions related to coordination, anti-coordination and cooperation in New World monkeys, Old World monkeys, and great apes, including humans, using identical methodologies.  We find that there are remarkable continuities of outcome across the primates, including humans, in coordination, however there are important differences in how each species reaches these outcomes.  These differences in mechanism may limit decision-making in other situations.  Indeed, despite similar outcomes in coordination decisions, species’ outcomes diverge sharply in the context of anti-coordination, possibly due to the limitations of their decision-making mechanisms. I consider both the similarities and differences in decision-making across different contexts and what these can tell us about the evolution of decision-making across the primates.

The effective size (Ne) is an important property of populations in evolutionary biology, population genetics and biological conservation. It represents how fast populations lose genetic diversity, and thereby provides information on expected future levels of inbreeding and evolutionary potential.

There are many ways to estimate Ne, and each method makes various assumptions on the past evolutionary trajectory of populations, on connectivity and population structure. As a consequence, a single dataset can yield very different Ne estimates, neither of which is necessarily wrong or right. However, a Babylonian speech confusion has arisen among geneticists on the exact meaning of Ne, which has far-reaching consequences for management.

Here I first review what drives the difference between the census size (Nc, the number of individuals in a population) and the effective size (Ne). Next, I  clarify how Ne is best used in a conservation context (and which methods and assumptions are generally valid to use), and third how this relates to conservation guidelines.

I then show how these guidelines have been implemented into Flemish policy relating to the European Habitats Directive, and how this is also translated into advice to the Convention on Biological Diversity. Finally, I provide examples of how we can broadly apply genetic principles into day-to-day conservation practices, even in the absence of genotypic or molecular information. 

Urbanization is a rapidly growing phenomenon that dramatically alters animals’ habitats and puts the survival of many species at risk. However, some species can also benefit from such changes, becoming ‘urban exploiters’. Wolves in Italy have (unexpectedly) adapted to highly anthropic environments. This has led to speculation that the prolonged proximity to human habitation, dependence on anthropogenic food sources and additional opportunity for hybridization with dogs may decrease wolves’ natural neophobic reactions towards humans and their artefacts, thereby increasing the potential for conflict. Here I present an overview of the methods being applied to test this hypothesis assessing the effect of urbanization on wolves’ feeding habits, their neophobic and risk-taking reactions, as well as their endocrinological and genetic profile. Based on our first year of data I highlight the challenges and limitations, but also the exciting possibilities of studying this population.

Konrad Lorenz Institute of Ethology, University of Veterinary Medicine, Vienna, Austria

Chemically defended animals often display conspicuous colour patterns that predators learn to associate with their unprofitability and subsequently avoid. Such animals, known as aposematic, deter predators by stimulating, for example, their visual and chemical sensory channels. Despite the multimodal nature of warning displays, their different components tend to be studied in isolation, with most studies focusing on visual signals. Furthermore, warning coloration is seldom studied beyond its role against predators. Using a poison frog (Dendrobates tinctorius) with intra- and inter-population variation in colour patterns, and elaborate parental care, we explore the behavioural and ecological enablers of the appearance and maintenance of colour pattern variation at different scales, and investigate the way(s) in which aposematism has also impacted their reproductive biology. Our findings: (1) highlight the importance of accounting for variation in both the visual and chemical components of warning displays, and testing whether or not relevant predators react differently to this variation; and (2) show how the aposematic phenotype in poison frogs serves as an umbrella trait for the evolution of complex offspring-caring activities in defended species.

Extreme heat weather events pose an immediate threat to survival and lead to negative effects on fitness. Hot temperatures (> 42 deg. C) have been associated with mass mortality of flying-foxes (Pteropus spp.) in eastern Australia. Heat stress is easily observed in this species because it roosts among the tree canopy in large colonies. Consequently, their response might serve as a ‘canary in the coal mine’, warning of adverse effects on less visible and more dispersed mammal species. Recent observations and model predictions indicate extreme heat events will increase in severity and frequency because of climate warming. It is important, therefore, to better understand the thermal physiological and behavioural responses of mammals to these environmental challenges.

I will present a summary our recent studies on the thermal physiology and ecology of the grey-headed flying-fox (Pteropus poliocephalus), a species that is exposed to a large range of thermal conditions. We have measured its physiological responses to hot conditions under controlled conditions in the laboratory and used bio-logging to record its body temperature and activity during exposure to natural conditions over long periods in the wild. These data provide insight into the mechanisms that allow these mammals to cope with variable environmental conditions, and identify the threshold conditions that challenge the species’ thermoregulatory capacity and cause mortality. I will also introduce our new project that uses biologging to measure the thermal, metabolic and nutritional physiology of wild-living koalas. We need these data to inform better biophysical models that can predict how habitat suitability of this iconic species will change under the increasing effects of climate change in eastern Australia.

Conservation Genetics Group, Senckenberg Research Institute and Natural History Museum, Frankfurt, Germany

The garden dormouse (Eliomys quercinus) is a native European rodent species that has suffered extensive range contraction and severe population decline during the last decades. While disappearing from 50% of its former distribution range during the last 30 years, the species has deserted large parts of Eastern Europe and is now considered extinct in some countries. At the same time, contrasting population dynamics are observed in its western distribution range, where garden dormice are regionally abundant and even occupy synanthropic habitats. As reasons for these opposing range dynamics and drastic declines remain unknown, we have started a long-term cooperation project, joining the efforts of different research institutions and conservation NGOs to investigate the underlying causes. Our research activities include the involvement of citizen scientists via an online reporting tool to assess the current distribution, regional diet composition, phenology as well as the pathology of the species. Further, we conduct RADseq analysis to infer phylogeography and delineate different conservation units. Preliminary genomic data show the existence of highly divergent genetic lineages, even on a local scale. Based on these findings, we have developed a reduced SNP panel allowing for distinguishing these lineages. This tool aids animal rescue centers with appropriate reintroduction of displaced Eliomys foundlings but also when establishing or reconnecting isolated populations of garden dormice. Ultimately, the joint project efforts aim to resolve the biology and ecology of Eliomys in order to develop a suitable conservation strategy and implement effective conservation measures for a species that has long been neglected in the legislation of European species conservation.

In most animal species, males produce conspicuous signals to attract mates such as loud and complex songs, bright and colorful body areas or strong chemical lures. Females use those ornament signals to choose a mate and males also use them to compete with rival males. This simple scenario of males displaying to potential mates and rival males has dominated our understanding of sexual selection. However, ornaments that increase attractiveness to females also make males particularly vulnerable to eavesdropper predators and parasites that exploit those signals to home in on their victim. The existence of eavesdroppers makes clear that the web of communication is much more complex than textbook versions. This more realistic perspective of communication prompts the question, how do eavesdroppers shape the evolution of mating signals? Using frog-biting midges as a case study this talk will unravel the evolutionary ecology of eavesdropping and how these unintended receivers affect the evolution of communication systems.

Developmental and transgenerational plasticity due to early-life environmental conditions have been suggested to play a role in adapting organisms to environmental challenges. Are they a solution to population persistence under rapid environmental changes? I summarize our recent empirical work on developmental and transgenerational responses to key environmental challenges (including temperature variation, resource competition, pollution and generalized early-life stress) using birds as a model system. I focus especially on the mechanisms and constraints underlying transgenerational and developmental plasticity, such as hormones and epigenetics. We are especially interested in traits related to energetics, as they are tightly linked to individual performance. In addition, briefly discuss the insights from our recent evolutionary modelling approaches on physiological traits. Understanding the relative contribution of different types of plasticity on organismal phenotypic variation and responses to environmental changes may help us predict responses to future changes.

College of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, China

The Bactrian camel includes various domestic (Camelus bactrianus) and wild breeds (Camelus ferus), and they are one of the few large livestock in the world that can survive in the Gobi desert. The natural habitat of the domestic Bactrian camel are the cold desert areas of Northeast and Central Asia, in contrast to the wild Bactrian camel is restricted to few remaining refuge areas, with their range extending to only three locations in China (Taklamakan desert, Gashun Gobi Desert and Arjin Mountains in the Lop Nur Lake region) and one in Mongolia (Great Gobi Strictly Protected Area ‘A’). Nowadays, the wild Bactrian camel is listed as Critically Endangered and its population is estimated to number from a few hundred to 2,000 individuals.

The Bactrian camels show several biological and physiological traits that may be connected with adaptation to such extreme heat and harsh and dry environments, including resistance to hunger and thirst, fluctuating body temperatures, tolerance of a high dietary intake of salt, and an immune system producing unique immunoglobulin. Recent genomic studies have revealed positive selection and immune gene loci, which may be related to desert environmental adaptation in this species. According to the archaeological research, the domestication of Bactrian camel probably occurred in 4500-5000 years ago; in the process of Bactrian camel domestication and breeding process, the rich local species resources were formed gradually. Here, we broadly review bactrian camel distribution and breed as well as recent progress in the determination of the camel genome, population structure and genetic variation of different Bactrian camel populations.

Primate field studies may cover extensive parts of individuals' lifetimes and may be essential to detect behavioural variations in the long term. For example, among primate vocal emissions, the most complex and intricate displays are singing and chorusing, typical to a few species and rarely investigated for long. Furthermore, indris (Indri indri) are the only Strepsirrhine among the singing primates, making them essential to understanding the evolution of primate communication. Indris live in the dense rainforests of Madagascar. They are duetting and chorusing, communicating at long distances with neighbouring groups. With my colleagues, we dedicated over 15-years of research studying the biology and communication of the indris. Indris are part of a very peculiar extended network where some critical features, such as territorial stability or developmental changes in song structure, could be detected because we observed them long-term. Another fascinating aspect of indris' communication is understanding how flexible the vocal output of individual lemurs was across the years, giving hints about the dispersal dynamics and the occurrence of intraspecific territorial behaviour. A few years after these studies began, what we know about the indris make them a model of comparison for studies of the biology of other primates and the investigation of complex, sequential phonatory events such as those involved in birdsong and primate singing.

Conditions experienced in early life can have long term consequences for individual fitness. My focus in this talk will be on the latter, and particularly on effects operating through the mother. Maternal state is affected by extrinsic factors such as nutrition levels or stress exposure, and intrinsic factors such as age I will discuss a number of such processes which we have investigated in both wild and captive bird species. I will discuss number of routes, which we have identified in experimental work on birds, whereby maternal state (particularly stress exposure and age) have long terms consequences for offspring health and longevity.