Intraspecific and interspecific larval interaction in Drosophila assessed by integrated fitness measure

Abstract

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.

Variation in selection and utilization of host crops in the field and laboratory byDrosophila suzukiiMatsumara (Diptera: Drosophilidae), an invasive frugivore

“…In no‐choice experiments comparing oviposition preference and offspring performance between blackberries, blueberries, raspberries and strawberries, most eggs were consistently laid in raspberries, and fewest in blueberries (Table ). Adult D. suzukii performance fitness may suffer when larvae develop in relatively crowded conditions . However, at the densities occurring in the present laboratory assays, development rate was faster in raspberries (Table ) that had high larval densities.…”

Species coexistence patterns in a mycophagous insect community inhabiting the wood-decaying bracket fungus Cryptoporus volvatus (Polyporaceae: Basidiomycota)

“…Atkinson & Shorrocks, 1981;Gilpin et al, 1986;Takahashi & Kimura, 2005). The niche partitioning hypothesis is supported by studies on Drosophila (Kimura, 1980;Grimaldi, 1985) but there is no experimental evidence for host specialization among Drosophila (Jaenike, 1978).…”

Chemical cues from competitors change the oviposition preference of Drosophila suzukii

“…In fact, high numbers of D. suzukii larvae have commonly been observed under field conditions (2.6–4.2 larvae per fruit) (Burrack et al, 2013; Yu et al, 2013), suggesting intraspecific competition occurs among D. suzukii larvae in nature. Empirical studies suggest that intraspecific competition reduces D. suzukii ’s fitness under the conspecific larval density observed in the field (Takahashi & Kimura, 2005; Hardin et al, 2015). Drosophila suzukii deposited significantly more eggs in blank media than in D. melanogaster pre‐inoculated medium, suggesting avoidance of interspecific competition by D. suzukii (Shaw et al, 2018).…”