Differences in prey capture in semiaquatic bugs (Heteroptera: Gerromorpha)

摘要

Feeding behavior has been investigated several times in different semiaquatic bugs (Heteroptera: Gerromorpha), but has never been directly compared between species from lentic and lotic habitats and different families. Time required to capture prey was investigated in five gerromorphan species: Aquarius paludum, Gerris lacustris, G.odontogaster (Gerridae), Velia caprai and V.gridellii (Veliidae). This experiment used live and dead prey and intact and artificially blinded bugs. The presence of vibrational stimuli (live prey) significantly decreased latency to capture prey in all species except G.odontogaster. This species was the only one where visual stimuli affected the response significantly (only with dead prey). Latency to capture in Velia spp. was significantly shorter than that in the three gerrid species. Capture efficiency differed significantly between Gerris and Velia spp.; both Velia species carried out unsuccessful attack attempts less frequently than did the Gerris species. Prey capture was quicker in treatments with live prey and/or intact bugs. No difference in capture efficiency was found between sexes. Aquarius and Gerris species from predominantly lentic habitats needed more time to capture prey than did Velia species, which live mostly in streams. This difference in feeding behavior can probably allow coexistence of gerrids and veliids at sites where their occurrence overlaps.