Abstracts (first author)
Spatial genetic structure and reproductive success of a parasitoid wasp in a competitive environmentPDF
In presence of a limiting resource, individuals can suffer from intraspecific exploitation competition. In the context of a parasitoid foraging for hosts, the effect of competition on fitness can be seen as a variation in reproductive success. The parasitoid wasp Hyposoter horticola is a specialist of the butterfly Melitaea cinxia. The wasp parasitizes the host larva just before it hatches from the eggshell. The host is therefore available for parasitism for a limited amount of time only (a couple of days). To cope with this time constraint, female wasps start to forage for host eggs before the eggs are ready to be parasitized. Hyposoter horticola is a good forager; females monitor several host clusters and visit them regularly until they are susceptible to parasitism. This behaviour increases the amount of time available for parasitism but, since the location of a host cluster is known by several wasps and each cluster can only be parasitized by a single wasp, it creates competition among the foraging females. In the Åland archipelago, Finland, the host butterfly lives as a metapopulation inhabiting a subset of 4 000 patches of suitable habitat. In order to conduct genetic analyses of the parasitoid population, we developed 14 microsatellite markers and genotyped 800 individuals collected from each of the host local populations during 2009. Performing clustering and relatedness analyses, we assessed the genetic structure of the population as well as the extent of the landscape area covered by females during foraging for hosts. We also analysed the effect of environment (host population locality, size and patch connectivity) and competition (local host and parasitoid density) on the proportion of females that reproduce and their reproductive success.