Abstracts - Deutsche Zoologische Gesellschaft

128 Evolutionary Biology Postersnumber of matings. I used a full-sib breeding design and found that both attractiveness and matinginvestment showed considerable heritability. Most importantly, there was a negative genetic correlationbetween attractiveness and mating investment: in families with attractive individuals, malesproduced smaller nuptial gifts than in families with less attractive males. These results demonstratean evolutionary trade-off between mating success and sperm competition success.P EB.8 - ENCharacterization of MHC (Major Histocompatibility Complex) class II in the EuropeanFire Salamander (Salamandra salamandra)J. Susanne Hauswaldt 1 , Martin Gajewski 2 , Sebastian Steinfartz 31Institut für Zoologie, TU Braunschweig; 2 Institute for Genetics, University of Cologne; 3 Departmentof Animal Behaviour, University of BielefeldMHC class II genes are involved in the presentation of exogenously produced antigens to the immunesystem. Their importance for co-evolutionary processes of host-parasite interaction in vertebrateshas been well described and variability of class II genes has been examined in natural populationsof many species of fish, birds, and mammals. Furthermore, some studies have demonstratedthat MHC plays a role in mate-choice interactions. In amphibians, the organization of the majorhistocompatibility complex (MHC) and its variability in natural populations has been studied in onlya few species. We have characterized MHC class II B cDNA sequences from a non-model urodelanspecies, the European Fire Salamander (Salamandra salamandra), and have developed primers toamplify a large part of exon 2, which contains the highly variable antigen-binding region. We areusing this marker to examine its variability in natural populations, as well as in the context of matechoiceexperiments.P EB.9 - ENSpeciation by hybridisation? Investigation of a grasshopper hybrid zone in GreeceAnja Klöpfel, Jan Sradnick, Norbert ElsnerJohann-Friedrich-Blumenbach-Institut für Zoologie und Anthropologie, Georg-August-UniversitätGöttingenThe two acridid grasshopper species Stenobothrus rubicundus and Stenobothrus clavatus are foundon the northern and southern slopes, respectively, of Mt. Tomaros in north-west Greece. Their habitatscross at the saddle area. Both species differ clearly from each other as far as the morphologyof the antennae, the position of the stridulatory pegs and numerous characters of the fore and hindwings are concerned. Most notably they are distinguished by their species-specific courtship behavioursdisplayed by the males which normally act a powerful prezygotic isolating mechanism ingrasshoppers. Despite of this, St. rubicundus and St. clavatus do hybridize on the saddle, and moreof 90% of the individuals are intermediate in this zone. These hybrids show an abundant numberof intermediate morphological and behavioural characters. Morphometrical measurements and molecularstudies reveal that the Tomaros populations of the two species differ clearly from populationson other mountains where either St. rubicundus or St. clavatus can be found. Obviously, on Mt.Tomaros these species do influence each other genetically to both sides of the hybrid zone. Since Mt.Tomaros is quite isolated from other mountains, such introgression of genes gives rise to speculationswhether in the long run new species might evolve by means of hybridization.