Intraspecific density effect was investigated for D. simulans, D. suzukii, D. auraria, D. rufa and D. immigrans, and interspecific density effect was examined for combinations of D. simulans, D. rufa and D. immigrans. Different numbers of their eggs were introduced to artificial substrates, and intra- and interspecific interaction were evaluated on the basis of per capita egg production of individuals (eggs) introduced. If individuals died before pupation, their per capita egg production was zero; if individuals survived to pupae, their per capita egg production was estimated from their size based on the relation between the pupal size and lifetime egg production. Per capita egg production thus estimated generally decreased with the increase of the density of conspecific larvae, although a slight increase was detected at high densities in some cases. When two species were introduced, per capita egg production of a species was reduced only when the larval density of co-introduced species was very high, suggesting weak interspecific competition. Interspecific interaction was asymmetric; the effect of D. simulans on D. rufa and D. immigrans was often significantly negative, but the effect of D. rufa or D. immigrans on D. simulans was not significant.
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics