How to divide a cake: The impact of resource distribution on life history behaviour of the burying beetle Nicrophorus vespilloides

Variation in types and distribution of resources promotes the evolution of competition and cooperation in animals. Small vertebrate carcasses, which are bonanza and unpredictable available for carrion-use insects are essential resources for the survival and reproduction of burying beetles N. vespilloides, a facultative communal breeding insect with parental care. Burying beetles bury carcasses for breeding, lay their eggs in or around the buried carcass and hatched larvae are fed by their parents. Resource distribution is related to variation in amount and availability. The aim of the research is to investigate whether resource distribution influences the degree of communal breeding. We expect that centralized resource distribution (i.e. large but less carcasses) promotes communal breeding, while decentralize resource distribution (i.e. small but more carcasses) promotes pair breeding. We constructed four contrast experimental groups at a field site in De Vosbergen, The Netherlands. Each experimental group has access to the same total resource amount in a certain area, however the groups vary in the number and size of resource units (i.e. three 30g dead mice, vs six 15g dead mice, vs one 30g and four 15g dead mice, vs two 30g and two 15g dead mice). We predict that in the group that have access to large but less carcasses: (1) there are no differences in the interspecific competition (i.e. the number and species of competitors) between these four groups, (2) burying beetles will compete more for gaining access to carcasses; (3) communal breeding will be more likely to occur, and (4) the per-capita reproductive output(brood size and mass of the brood) will be lower as a consequence of a more pronounced trade-offs between investment for competition (fighting) and reproduction.