Experiments with iLymantria dispar/i larvae do not support the idea of physiological adjustment to host individuals by insect herbivores

摘要

All organisms have to cope with spatial and temporalheterogeneity of the environment. At short temporal and small spatialscales, organisms may respond by behavioural or physiological mechanisms. Totest for physiological adjustments to variation in host quality among treeindividuals within a host species, we performed a transfer experiment in aclimate chamber using larvae of the polyphagous gypsy moth (Lymantria dispar). We rearedlarvae for two weeks on leaves of one of three Quercus robur individuals. We founddifferences in the growth rate of larvae across the host individuals, whichindicate that the oak individuals differed in their quality. Furthermore,families of larvae varied in their growth rate and there was variation amongthe families of gypsy moth larvae in response to leaves from the differentoak individuals. After two weeks we offered larvae either leaves of the sameor a different individual of the three oaks. We found no effect oftransferring larvae to a different tree individual. The results thus do notsupport the idea of physiological adjustment of a generalist insectherbivore to variation in leaf quality among host individuals.