Evolutionary ecology of sympatric Catocala moths (Lepidoptera: Noctuidae) 1. Experiments on Larval Foodplant Specificity

Abstract

Larval food plant specificities are presented for 31 Nearctic species of the genus Catocala whose larvae feed on trees in the families Juglandaceae, Fagaceae and Salicaceae. Feeding preferences were determined in the laboratory and survival and growth rates in no-choice situations in the field in Connecticut. In choice tests, larvae of the Juglandaceae, Fagaceae and Salicaceae feeders fed on only their own plant family. Among the Juglandaceae feeders, 2 species fed on walnuts, 2 fed on pecans (section Apocarya of Carya) and the remaining 14 fed on hickories (section Eucarya of Carya). All the hickory feeders preferred shagbark hickory (Carya ovata), and 6 species specialized on it. Among the Salicaceae feeders, one species fed on willows (Salix spp.) and 6 on poplars (Populus spp.). Food plant preferences were not clearly defined in species feeding on Fagaceae. Larvae usually selected the favoured food plant as a resting site. Preferences broadened as larvae matured, and the Juglandaceae and Salicaceae feeders preferred young to old leaves. In nearly all cases, survival and growth rates were highest in the field on the food plants preferred in arena tests.