Forschung

Ongoing Research Projects

Conservation Biology
Michael Schöner showing a Bornean fruit bat to locals.

Projects are/have been funded by various foundations, including the German Science Foundation (DFG), the VolkswagenStiftung, several private foundations, such as the Bristol Foundation and governmental organisations such as the highway department Northern-Bavaria (ABDNB) and the federal agency of nature conservation (BfN).

In close collaboration with local researchers and conservation biologists, we study threatened bat species in different regions of the world, using a combination of behavioural, ecological, and molecular methods. In the field, we use automatic monitoring of animals marked with PIT-tags, radio-telemetry, thermography, and infrared-video monitoring to assess the habitat use and behaviour of our different study species (e.g. Kerth & Melber 2009). To investigate genetic structures, dispersal rates, inbreeding coefficients and individual reproductive success in wild populations we use genetic methods, including analyses of nuclear and mitochondrial DNA microsatellites as well as DNA sequencing (e.g. O’Donnell et al. 2015). Overall we aim at combining research on basic scientific questions with applied conservation. Our studies contribute knowledge and data for national conservation management of threatened bats in different regions of the world (Central and South-Eastern Europe (e.g. Bulgaria, Germany and Serbia), the Caucasus region (Georgia and Russia), as well as Central America, Borneo, and New Zealand). We aim on supporting local conservation authorities, which in several of the aforementioned countries cannot afford to gather such data within the framework of national research programs. Besides their scientific value and implication for conservation, our cooperative international projects often have capacity building effects on future research projects on threatened animals in the respective regions. In Germany we for example have a close collaboration with the Nature Park “Nossentiner-Schwintzer Heide”. Last but not least, education of young scientists from the partner countries involved (e.g. Bulgaria, Brunei, Georgia, Russia, Serbia), via transfer of sophisticated methodological knowledge and “evolutionary thinking”, will be important for future biological projects that try to answer scientific questions of high standard and international significance and that are crucial for nature conservation.

Upper left: Individually marked Bechstein’s bat. This broad winged species cleans its prey from the vegetation (photo by M. Melber). Lower left: Individually marked barbastelle’s bat. This species has more pointed wings, capturing its aerial prey in open space. While barbastelle bats regularly crossed a German motorway (upper right) during foraging and roost switching, only few Bechstein’s bats crossed the same motorway during foraging - through an underpass - but none of them crossed the motorway while roost switching (Kerth & Melber 2009). Newly built underpasses (lower right) have been discovered fast by bats of different species.
Co-evolution of Host-Parasite Systems

funded by the VolkswagenStiftung

We combine genetic data (mtDNA and nucDNA) as well as ecological and demographic data (infestation rates) to compare the population structures of two blood-feeding ectoparasites, the wing mites and the bat flies, to that of their hosts, different bat species. Wing mites and bat flies differ in the transmission mode (exclusively transmitted by body contact versus partially transmitted via the communal bat roost; Reckardt & Kerth 2009). As a result, the behaviour and the social structure of the host are expected to influence population structures differently in the two parasites. To test this prediction, we compare the genetic population structures of all interacting species at different spatial, ecological, and time scales (Bruyndonckx et al. 2009, van Schaik et al. 2014, 2015). The study benefits from the already existing data on the ecology, behaviour, and population genetics of the Bechstein’s bat in two of its glacial refuges, the Balkan and the Caucasus (Kerth et al. 2008). Moreover, we established genetic markers (polymorphic mtDNA sequences and nucDNA microsatellites) for the wing mites (Bruyndonckx et al. 2009) and the bat flies (van Schaik et al. 2015). The combination of data on the ecology, behaviour, and genetic structure of host populations throughout their range with data on the demography and genetic structure of parasite populations allows us to address open questions on host-parasite co-evolution. Such a comparative study of host-parasite dynamics can reveal key information on host life history traits that favour parasite transmission and affect host-parasite co-evolution and local adaption patterns.

Emerging Diseases and Virus Transmission in Bats

Two projects funded by the German Science Foundation (DFG Priority Program “Ecology and Species Barriers in Emerging Viral Diseases” (SPP 1596)) and one project by Bat Conservation International (BCI).

Understanding the antagonistic nature and evolutionary dynamics of host-pathogen relationships requires information on the genetic covariation and ecological interactions of hosts and pathogens. However, the interplay between the processes that influence covariation of hosts and pathogens is largely unknown. It is for example unclear to what degree ecological conditions and social barriers affect host dispersal and the degree of association among different host species influence pathogen transmission within and among host species. In two projects funded by the DFG we investigate the links between the habitat structure, ecology, behaviour and genetic structure of European bat species (first project in collaboration with the Institut für neue und neuartige Tierseuchenerreger, Friedrich-Loeffler Institut) and neotropical bats (second project in collaboration with the Institute of Virology, Universität Bonn) on the one hand and the genetic structures and prevalence of different viruses that infest bats, on the other hand. The aim is to understand the relationship between ecological conditions and life history traits of the interacting species that may help viruses to overcome species barriers and colonize novel hosts. In a third project funded by BCI we are interested in determining the distribution of Geomyces destructans, the causative agent of White-Nose Syndrome, across Eurasia. We investigate its population structure in relation to bat population structure and its relationship with the invasive North American population of this fungus. This includes investigating the diversity of Geomyces species found across Eurasia and their relationship with Geomyces destructans. Identifying where Geomyces destructans reproduces (the reservoir) and how it is transmitted from bat to bat, from the environment to bats and vice-versa is also a topic of our research. The project on Geomyces destructans is run by Sebastien Puechmaille and co-workers.

Bat with White Nose Syndrom that is caused by the fungus Geomyces destructans.
Cooperation, Coordination and Cognition in Animal Groups

Funded by the German Science Foundation (DFG: bats) and the Bristol Foundation (hornets).

Our aim is to study the causes and consequences of sociality on different levels (genotype, phenotype, population), using different bat species and social insects (hornets, Vespa crabro) in the wild. One focus is on the social cognition and group decision-making in fission-fusion societies, where individuals benefit from cooperation within their group but at the same time are likely to differ in their interests, experiences, personalities and abilities. An exciting open question is whether fission-fusion behaviour requires special communication, decision-making, and cognitive skills. This question can only be answered with comparative and experimental studies that involve long-term data on free-ranging populations. Currently, we focus on the Bechstein’s bat, the brown long-eared bat and the Natterer’s bat for which we have long-term data on the social, demographic, and genetic structure of colonies. In all three species, colonies frequently switch communal roosts and colony members have to make group decisions daily about where to roost (Kerth et al. 2006, Fleischmann et al. 2013, Fleischmann & Kerth 2014). Colonies regularly split into subgroups and hence are fission-fusion societies (Kerth & König 1999, Kerth et al. 2011, Fleischmann & Kerth 2014). At the same time, colonies of the three bats species differ in their structure (within and between the species), e.g. their size, in the proportion of non-reproductive females, the number of matrilines per colony, and the presence of males. Thus, bats provide excellent opportunities to study the effect of group heterogeneity and fission-fusion behaviour on group decisions, cooperation and social cognition. We developed techniques allowing for automatic monitoring of PIT-tagged bats moving between different roost sites and to carry out field experiments allowing for manipulating the behaviour and to influence the information of individuals (Kerth et al. 2006, Fleischmann et al. 2013). We use our long-term data on bats to compare social coordination and group decision-making in heterogeneous bat colonies to that in more homogeneous colonies of hornets.

Left: Individually marked members of a Bechstein’s bat colony (photo by K. Weissmann) Upper right: Hornet queen carrying a PIT-tag (photo by M. Melber). Lower right: Social network of a large Bechstein’s bat colony (picture by N. Perony).
Series of six in vivo MRIs of a wild Bechstein’s bat. After the MRI scanning, the bat is marked with a PIT tag, released to its natal colony, and subsequently its behaviour can be followed in the field.
Interactions between Carnivorous Pitcher Plants and Bats in Borneo

This project is funded by the German Science Foundation (DFG).

In collaboration with Professor Ulmar Grafe, Univ. of Brunei, Dr. Ralph Simon, Univ. of Nuremberg-Erlangen, Dr. Charles Clarke, James Cook Univ., and Professor Dr. Alex Widmer ETH Zürich, we study an extraordinary mutualistic interaction between bats and carnivorous pitcher plants in Borneo. We showed that the pitcher plant Nepenthes hemsleyana gains about one third of its nitrogen demand from faeces of Hardwicke’s woolly bats (Kerivoula hardwickii) that exclusively roost in the plant’s aerial pitchers (Grafe et al. 2011). The bats, in turn, benefit from these high quality roosts by a favourable microclimate and a low parasite infestation risk (Schöner C. et al. 2013). As the benefits strongly outweigh the costs for both partner species (Schöner C. et al. 2015), the interaction can be classified as mutualism. In comparison with closely related species N. hemsleyana is a poor insect trap but is likely to have evolutionary adaptations to serve as a day roost for bats. One of these traits that facilitate bat roosting is the elongated back wall structure of the pitchers that is missing in closely related species. This structure is highly attractive for the bats as it strongly reflects the echolocation calls of the bats. We could show that this trait helps the bats to find and identify new roosts. This is especially important in the dense vegetation of the peat swamp forests where these plants and bats occur (Schöner M. et al. 2015). To investigate the fascinating interaction, we use a combination of: 1) field and lab observations of the bats’ behaviour towards pitcher plants, 2) field and lab experiments measuring the benefits and costs, which the pitcher plants obtain from the bats, 3) genetic analyses of population structures of bats and pitcher plants, and 4) chemical analyses of the nitrogen contents of pitcher plants growing under natural conditions in the field and under controlled conditions in the lab. Allowing for experimental manipulation, the pitcher plant-bat system offers an excellent opportunity to examine an exceptional form of interspecific relationship between plants and mammals.

Caroline and Michael Schöner inspecting a carnivorous pitcher plant in Brunei.

Current Research

Our research is multi-disciplinary and addresses questions at the interface of evolutionary, behavioral, and conservation biology. We study social animals and their parasites and pathogens, and work both in the field and the laboratory. In several bat species, we investigate cooperative behavior, dispersal, mating systems, group decision-making in fission-fusion societies, host-parasite/pathogen dynamics, mutualistic inter-specific interactions, as well as basic and applied questions in animal conservation. We use our data to understand processes relevant for the protection of threatened species and suggest directions for habitat management and the monitoring of populations.
 
Combining genetic data with field observations revealed that Bechstein’s bats (Myotis bechsteinii), the species with which we work for more than 20 years, live in complex social groups that are characterized by fission-fusion dynamics and cooperation. Females transfer information about communal roosts, allo-groom each other, and make context-dependant group decision about where to roost next. We found evidence for complex communication, group recognition, and context-related social interactions. In several bat species, living in different tropical and temperate ecosystems, we study how social systems and genetic population structures are influenced by different mating systems, habitat features and dispersal strategies. We found dispersal behavior to differ strongly between species, ranging from strict female philopatry to the dispersal of both sexes, with differences in dispersal patterns being linked to differences in mating systems. We use social network approaches to assess the flexibility of social structures within and between species. Despite intra- and inter-specific variation of bat social structures, the social system of a given species can be conserved over large geographical distances and over populations that live in different environments and have different phylo-geographic histories. Overall our research on bats contributed to the emerging understanding that bat social systems are far more complex than was previously imagined.
 
During the last 20 years, we established a long-term study on the Bechstein's bat in Central and Eastern Europe. This project, which now includes several international collaborations allows detailed insights into the influence of the social structure and the environment on the genetic composition, ecology, and behavior of bat populations, and the relationships with two ectoparasites (wing mites and bat flies) as well as several viruses. In addition, since more than 10 years, we have collected comparable field and genetic data from brown long-eared bat (Plecotus auritus) colonies and more recently from Natterer’s bat colonies where individuals are also marked with PIT-tags. We use these long-term data to study the demography of free-ranging populations and to assess the factors influencing age-related mortality in bats. Our data have important implications for conservation and facilitated the design of protective areas (FFH) in Germany and Bulgaria. The available genetic and field data provide an extensive database on which our future projects can build upon.

Research Collaborations

  • "Conservation genetics of Chalinolobus tuberculatus, a bat endemic to New Zealand": Dr. C. O’Donnell and Dr. J. Monk Depart. of Conservation, Government of New Zealand.
  • "Demography and age-related mortality of bats": Dr. A. Scheuerlein, Dr. Jutta Gampe, MPI for Demographic Research, Rostock.
  • "Ecology and population structure of the Bechstein's bat and its parasites in its glacial refugia": Dr. S. Gazaryan, Eurobats Bonn, I. Natradze, Ilia Chavchavadze State Univ., Tiflis and B. P. Petrov, National Museum of Natural History, Sofia.
  • "Ecology and species barriers in emerging viral diseases": Prof. Dr. C. Drosten, Institute of Virology, Universität Bonn, Prof. Dr. S. Sommer, PD Dr. Marco Tschapka, Institut of Evolutionary Ecology and Conservation Genomics, University of Ulm, Germany
  • "Forschung. Umweltbildung. Naturschutz - Mit FUN in die Wildnis!": Ralf Koch, Martin Post, Naturpark Nossentiner Schwinzer Heide, Christoph Treß, Johannes Treß
  • "Interactions between carnivorous pitcher plants and bats in Borneo": Prof. Dr. U. Grafe, Faculty of Science, University Brunei Darussalam, Dr. C. Clarke, James Cook University Cairns, Australia, Dr. R. Simon, Friedrich-Alexander-University Erlangen-Nuremberg, Prof. Dr. A. Widmer, ETH Zurich, Switzerland.
  • "Molecular Basis of Aging in Bats": Prof. Dr. E. Teeling, Dublin University, Ireland.
  • "Range expansion in the lesser horseshoe bat": Prof. Dr. E. Petit, University Rennes, France, Wigbert Schorcht, Martin Biedermann, Nachtaktiv, Erfurt, Germany.
  • "Social networks in fission-fusion societies": Prof. Dr. F. Schweitzer, Department of Management, Technology, and Economics, ETH Zürich.
  • "Socio-genetics in the frog-eat bat Trachops cirrhosus": Dr. R. Page, Smithsonian Tropical Research Institute, Panama.
  • "Viruses in bats": Prof. Dr. M. Groschup, Dr. A. Balkema Buschmann, Institut für neue und neuartige Tierseuchenerreger, Friedrich-Loeffler Institut, Bundesforschungsinstitut für Tiergesundheit.