Victoria Fiorentino

Gregarious feeding by insect herbivores is a widely observed, yet poorly understood, behavioral adaptation. Previous research has tested the importance of group feeding for predator deterrence, noting the ubiquity of aposematism among group-feeding insects, but few studies have examined the role of feeding facilitation for aggregates of insect herbivores. We tested the hypothesis that group feeding has facilitative effects on performance of the saddleback caterpillar, Acharia stimulea Clemens, a generalist herbivore of deciduous trees. In an understory forest setting, we reared caterpillars alone or in groups on two different host plants, white oak (Quercus alba L.) and American beech (Fagus grandifolia Ehrlich), and recorded multiple measures of insect performance during regular field censuses. As predicted, A. stimulea caterpillars feeding in groups on white oak had increased relative growth rates compared with caterpillars feeding alone, and the magnitude of this facilitative eff...