PD Dr. Björn Siemers

(† May 23 2012)

Provisional Leader of the Research Group

Prof. Dr. Lutz Wiegrebe

Contact Person

Ilse Bayer

Phone:+49 8157 932-375Fax:+49 8157 932-344


Max Planck Research Group Sensory Ecology

The sensory and cognitive abilities of animals influence their survival chances significantly. Every species is specifically adapted to their own ecological niche, the sum of all factors that make up their biotope regarding roosts, mating and especially foraging. Our research investigates the evolutionary interplay between an organism’s sensory and cognitive abilities and its ecological niche.

An animal's sensory abilities determine which environmental signals are perceived and how the different sensory perceptions are gathered. Cognitive abilities mean the power to process these perceptions.

In order to distinguish between phylogenetic, evolutionary and ecological effects, we use a comparative approach, working on bats (Vespertilionids and Rhinolophids), shrews, and nocturnal primates (particularly mouse lemurs in Madagascar).

All representatives of the three groups face a similar challenge, finding their food, i.e. insects, close to, in and on vegetation. Whereas the flying bats and the tree-climbing lemurs have to deal with this in a 3-dimensional space, the ground-dwelling shrews live in a 2D-environment. Therefore, among other things, the way the animals catch their prey differs as well. Additionally, the three groups differ in their lifespan, their social life and their ability to learn foraging strategies. Thus, the three groups constitute an excellent model system to study how evolution adapts animals’ sensory and cognitive abilities to their ecological niche.

These observatios rise the intriguing question of how the differences in sensory and cognitive abilities influence the animals’ coexistence. One possible outcome would be reduced competition, e.g. if one species was exclusively able to perceive prey of a certain size and therefore hunted this prey exclusively, another species however is able to switch to smaller prey because it has the sensory abilities to do so. The overlap between the foraging niches is reduced and coexistence becomes possible (sensory niche partitioning).

Another important factor for individuals of the same or different species coexisting in one habitat is communication. Sensory and cognitive abilities play an important role here as well. Are the animals capable of perceiving, recognizing, understanding each other? Our research tries to answer these questions as well.

Recent mammals’ ancestors were small, probably nocturnal or crepuscular insectivores, just like our model organisms. In the long term, our research will help us to understand mammal evolution since the Mesozoic era.

In order to quantitfy our research questions, we use bioacoustic, behavioural- and sensory- physiological methods as well in field studies as in lab experiments. We develop working hypotheses for the lab based on field data. Conversely, experimentally derived theses have to be tested in the wild. Our field station in Tabachka, Bulgaria offers excellent conditions to verify the results won from captive animals. In two flight rooms experiments can be conducted under strictly controlled conditions, mobile flight tents present a smooth transition to field conditions. In Tabachka, we collaborate closely with the Rusenski Lom Nature Park (www.lomea.org).

We use behavioural, ecological, bioacoustic and sensory-physiological methods and closely combine field studies with more tightly controlled lab experiments. On the basis of the data obtained in the field, we develop working hypotheses for the experimental studies in the lab, at our field station in Bulgaria or in mobile flight tents for bats. Conversely, predictions from experimentally based hypotheses are tested in field studies to confirm the ecological relevance of the findings from animals in captivity.

Publications of the Siemers group

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