Preference and Performance of the Leaf BeetleDisonycha pluriligata(Coleoptera: Chrysomelidae) in Arizona and Comparisons with Beetles in Finland

Abstract

Four Arizona willows ( Salix bebbiana, S. exigua, S. laevigata, S. lasiolepis ) were offered to adult beetles and larvae of Disonycha pluriligata (LeConte) in a series of food choice experiments. Adult Disonycha were very selective, feeding 93.4% of the time on one species. Disonycha larvae were also very specific, although less so than adults, feeding on the preferred willow species 80.0% of the time. The order of acceptance ( S. exigua, S. bebbiana, S. lavigata , and S. lasiolepis ) by adults and larvae was almost the same. The survivorship of larvae fed on these willows also showed a uniform pattern across the species that followed adult and larval choice. When offered a choice between male and female S. exigua , adults fed on females more than males, but larvae did not discriminate. In comparison with data on Finnish chrysomelid beetles on willows, Disonycha was more specific in utilization patterns of willow species in the field, in experiments on adult choice, and in survivorship of larvae on hosts. Larval choice was not tested in the Finnish study.