Abstracts - Deutsche Zoologische Gesellschaft

Evolutionary Biology Symposium 39O EB.2 (Sa) - ENCollective anti-parasite defence in antsLine V. Ugelvig, Sylvia CremerLehrstuhl Biologie I, Universität RegensburgLiving together in social groups has many benefits but comes at the cost of a high disease transmissionrisk between group members. To counteract this threat, social insects have evolved collectiveanti-parasite defences that combine the hygienic behaviours and physiological immune systems ofall group members to a “social immune system”. Infection of single workers of the invasive gardenant, Lasius neglectus, with the fungus Metarhizium anisopliae leads to behavioural changes of theseindividuals. They avoid contact to the larvae, potentially to prevent parasite transmission to thesusceptible brood in the colony. However, contact rates to non-infected adult workers of the colonyare not reduced. We found that this social contact between infected individuals and their naïve groupmembers gives a protective advantage to the naïve individuals when later being challenged withthe parasite themselves. We currently study the underlying mechanisms of this protective effect byanalysing the disease transmission dynamics in colonies and measuring the immunocompetence ofgroup members.O EB.3 (Sa) - ENFighting fungi as parental investment in the European beewolf (Hymenoptera,Crabronidae)Gudrun Herzner, Tobias Engl, Erhard StrohmInstitut für Zoologie, Universität RegensburgParental investment may be multifaceted and comprises not only the provisioning of offspring withfood but e.g. the protection of progeny from pathogens and competitors. Females of the Europeanbeewolf Philanthus triangulum hunt honeybees as food for their progeny. These provisions are severelythreatened by mould fungi. However, beewolves have evolved a mechanism to counter thisthreat. Females lick the surface of their honeybee prey extensively prior to oviposition. During thistreatment, the prey is embalmed with huge amounts of a secretion of long-chain hydrocarbons.This embalming prevents the condensation of water on the prey surface and decelerates the growthof moulds. It was already known that the hunting of the prey constitutes an important part of theparental investment. Here, we asked whether the embalming of the prey also represents parentalinvestment. Parental investment was defined by Trivers as all expenditures of a parent that promotesthe survival of the current offspring, but reduces the future reproductive potential of the parent. Inthis study we provide evidence that, first, there is a correlation between the amount of secretionand its effect against fungi. Hence, the embalming of the bees has clear benefits for the larvae. Second,experimental manipulations show that the embalming may be costly for the females. Thus, thetreatment of prey by beewolf females probably constitutes another component of the multifacetedparental investment of beewolves.