BEHAVIORAL-CORRELATES OF SELECTION FOR OVIPOSITION BY DROSOPHILA-MELANOGASTER FEMALES IN A PATCHY ENVIRONMENT

The behaviour of females from lines selected for high (H) and low (L) aggregated oviposition was compared in an environment consisting of di screte patches of resource available for larval development. Ovipositi on behaviour was influenced by the conformation and by the texture of the substrate, but this does not account for the selective differences in levels of aggregation which are under genetic control. The distrib ution of males of both selected populations tends to be overdispersed across resource patches. This observation is consistent with male terr itorial behaviour. The dispersal patterns of females of the two select ed populations differ significantly. H females show a contagious distr ibution whereas the distribution for L females is more nearly random. Differences in adult female dispersion are likely to be a significant factor contributing to aggregated oviposition. The level of aggregated oviposition affects the pattern of progeny survival when the unit of resource in each patch is small.