The Chrysomelidae: A useful group for investigating Herbivore-Herbivore interactions

Abstract

The Chrysomelidae comprise one of the most abundant and diverse families of herbivorous insects. A large proportion of chrysomelid species are monophagous or oligophagous, and the group has long been used to investigate the evolution of host specificity in phytophagous insects (Mitchell 1981, Smiley 1982, Crowson 1981, p. 589, Jolivet 1986). Of 139 chrysomelid genera in North America, 46.8% use only one genus of host plant, and an additional 46.7% use between two and five genera (Mitchell 1981). For 298 native N. American species, the average number of host plants used is approximately 1.5 plant species per species of chrysomelid (data tabulated by J. Kochmer from Wilcox 1979). In many chrysomelids, both adults and larvae feed on the same host resource (Raupp and Denno 1983). a fact that may have a large influence on patterns of host use in the Chrysomelidae. Although several other insect orders contain monophagous species, adult and larval resources are often different (Mitchell 1981, Price 1975). For example, in monophagous Lepidoptera. adult butterflies require nectar or pollen for their metabolic maintenance. Adult flight and alighting behaviors are commonly phasic, and flight paths can be alternately affected by densities of flowering plants (adult nectar resources) and larval resources (Stanton 1983, Gilbert and Singer 1973). The different needs of the two life stages may influence the dispersion of eggs in particular habitats (Murphy 1983, Gilbert and Singer 1973).