Martin Kalbe Max-Planck Institute for Limnology, Dep Evolutionary Ecology, D Title Parasites as selective forces in ecological diversification - examples from stickleback Abstract Parasites can be regarded as one of the most rapidly changing selective factors in animal populations. The Red Queen Hypothesis describes the relationship between hosts and parasites as an evolutionary arms race, in which both partners continuously have to adapt to each other in order to maintain their own fitness. Especially in macroparasites with complex life cycles, which require the presence of different intermediate and definitive hosts, as well as suitable ecological and environmental conditions for successful transmission, every host population probably is exposed to a unique assemblage of parasites. Three-spined sticklebacks (Gasterosteus aculeatus) are ideal vertebrate model organisms to study the evolution of host-parasite interactions on a small geographical scale. In northern Germany, it has been shown that sticklebacks e.g. from river and lake populations can be regarded as genetically distinct ecotypes, which also harbour different habitat-specific parasites. We monitored different stickleback populations and their macroparasite infections over several generations. In order to investigate adaptations of the hosts, we analysed basic immune functions of sticklebacks from different populations, exposed to several sympatric and allopatric parasites, either in lab infection experiments or in enclosure studies in the field. Our results indicate an adaptation of sticklebacks to their sympatric parasite fauna, which probably favours local over immigrant individuals in their competition for resources and mating partners. This might lead ultimately to reproductive isolation of populations. CV 1994 - 1998 PhD, Institute for Zoology I, University of Erlangen-Nuremberg, Germany: Thesis: "Chemooorientration of miracidia towards their host snail: signals and specificity" (in German) 1993 Diploma thesis entitled: "Miracidium of Schistosoma mansoni: elicitors for the chemoorientation towards the intermediate host" (in German), Institute for Zoology I, University of Erlangen-Nuremberg, Germany Professional experience 1994 - 1998 Research assistant at the Institute for Zoology I, University of Erlangen-Nuremberg, Germany 1998 - 2000 Postdoctoral researcher at the Institute for Zoology I, University of Erlangen-Nuremberg, Germany 2000 - present Research scientist at the Max Planck Institute for Limnology, Dept. Evolutionary Ecology, Ploen, Germany Research interests Evolutionary and ecological parasitology Host-parasite Co-evolution Parasite transmission strategies Parasites of fish Selected recent publications Rauch G, Kalbe M & Reusch TBH (2006) Relative importance of MHC and genetic background for parasite load in a field experiment. EVOLUTIONARY ECOLOGY RESEARCH 8 (2): 373-386 Kalbe M & Kurtz J (2006) Local differences in immunocompetence reflect resistance of sticklebacks against the eye fluke Diplostomum pseudospathaceum. PARASITOLOGY 132 (1): 105-116 Kalbe M, Haberl B, Hertel J & Haas W (2004) Heredity of specific host-finding behaviour in Schistosoma mansoni miracidia PARASITOLOGY 128 (6): 635-643 Wegner KM, Kalbe M, Kurtz J, Reusch TBH & Milinski M (2003) Parasite selection for immunogenetic optimality. SCIENCE 301 (5638): 1343 Kalbe M, Wegner KM & Reusch TBH (2002) Dispersion patterns of parasites in 0+ year three-spined sticklebacks: a cross population comparison. JOURNAL OF FISH BIOLOGY 60 (6): 1529-1542 Institution address Martin Kalbe Max-Planck Institute for Limnology, Dep Evolutionary Ecology August-Thienemann-Strasse 2 D-24306 Ploen Phone +49 (0) 4522 763 256 Fax +49 (0) 4522 763 310 kalbe@mpil-ploen.mpg.de