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Prey selection by the dobsonfly larva, Protohermes grandis (Megaloptera: Corydalidae)
Author(s) -
HAYASHI FUMIO
Publication year - 1988
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/j.1365-2427.1988.tb01713.x
Subject(s) - predation , biology , larva , predator , ecology , range (aeronautics) , zoology , materials science , composite material
SUMMARY 1. Prey selection by the dobsonfly larva, Protohermes grandis (Thunberg), was studied in stony riffles of the Yataro River, central Japan. The density, size distribution and taxonomic composition of available prey were assessed for 2 years. In order to know the encounter rate between prey and this ambush predator, prey mobility was also estimated from patterns of colonization of experimentally detiuded stones. 2. Foregut analyses revealed that maximum size of prey eaten increased with larval size, and large larvae did not take the smallest prey in spite of high availability in all seasons. 3. Charnov's (1976) optimal diet model quantitatively predicted such size‐selective feeding under seasonally fluctuating conditions of water temperature and prey availability. Larvae maximized the feeding rate by selecting prey. 4. Maximum width of prey eaten coincided approximately with larval mandible length. Mandible size seemed to play an important role in the selection of prey in the optimal size range.