Guided by Tinbergen’s four questions, we aim to understand the evolution of fish ecology and behaviour by asking: What is a given trait’s adaptive value? How is the expression of a given trait controlled? How is a given trait developed throughout an individual’s ontogeny? And What is the phylogenetic distribution of a given trait throughout the tree of fish life?
The ‘given traits’ that we are most interested in are those linked to sociality and life history, particularly those involved in the establishment and maintenance of complex societies and those that affect the pace-of-life and lifespan of individuals and species. As such, our preferred group of fishes are the cichlids of Lake Tanganyika. It is in this East African Rift Valley Lake that fish have evolved the greatest diversity of social behaviours and a vast range of life history strategies.
We apply a combination of controlled laboratory experiments and field research to conduct detailed behavioural and physiological experiments, as well as gathering ecological data in our species’ natural habitat.
Organisms have to adapt to changing environments in order to survive. Behavioural flexibility via learning plays an important role in such adaptations during an individual’s lifetime. We explore how stress reactivity influences behavioural flexibility in a highly social cichlid, Neolamprologus pulcher.
Physiological and neuroendocrine mechanisms of behaviour
We have established novel methods to unravel the complex interplay of hormones and genes that regulate behaviour. We are particularly interested in how the stress-axis modulates behavioural phenotypes, but we are also interested in the effects of isotocin (the non-mammalian homolog of oxytocin), dopamine and serotonin on the regulation and modulation of social behaviour.
The influence of current and early-life environments on cognition, emotions and behaviour
Cognitive abilities are well studied in large-brained animals (e.g. primates) but much less is known about cognition and emotions in fish. Recently, we established a reversal-learning paradigm to test for learning and reversal-learning abilities in N. pulcher. We are also interested in cognitive bias and spatial learning tests to gain a comprehensive understanding of the full repertoire of fish cognitive abilities.
While living in groups can confer a multitude of benefits, ranging from reduced predation risk to increased foraging efficiency and enhanced reproduction, it also introduces conflicts of interest among group members. Nevertheless, we can observe astonishing forms of sociality and cooperation in the fish that we study. We thus want to understand how cichlids can resolve conflicts.
Telomeres are the protective caps at the ends of linear chromosomes. Throughout an individual’s life, telomeres shorten in many organisms. Once telomeres become too short, they inhibit cell replication, thus stopping various regenerative processes. We thus want to understand why cichlids differ in the length of their telomeres and how well they maintain that length over their lives.
A general trend among animals is for larger organisms to have a relatively lower metabolic rate. Because larger animals also tend to live longer lives, metabolic rate has long been suggested as a key player in the evolution of life histories. We thus want to understand how metabolic adaptations allow cichlids to reach such different sizes and have such different lifespans.
- Arne Jungwirth, Dr. (Science)
- Stefan Fischer, Ph.D. (Science)
- Stefan Graf (Technical assistance)
- Martina Krakhofer (Animal keeper)