Trophic associations and specialization of phytophagous beetles (Coleoptera: Chrysomeloidea,Curculionoidea) in the east of the Russian Plain

Data on the trophic associations of beetles with plants in the east of the Russian Plain are summarized and comparative analysis of host specialization of different groups of phytophagous beetles is performed. In terms of the width of the regional trophic spectrum, monophages and narrow oligophages prevail among the Curculionoidea as a whole and in the families Curculionidae and Apionidae in particular, while moderate and broad oligophages prevail in the Chrysomeloidea and in the family Chrysomelidae. Two-thirds of the regional fauna (66%) of Curculionoidea are closely associated with plants of one genus; by contrast, in Chrysomeloidea almost 40% of the species can develop on plants from different genera of one family, the fraction of the narrowly specialized forms comprising only 43%. The higher level of trophic specialization of weevils (Curculionidae, Apionidae) and seed beetles (Bruchidae), as compared to leaf beetles (Chrysomelidae), is probably due to the larval endophagy of most species of these families. Analysis of the distribution of beetles over host plants has shown that the specialized forms are associated with plants of 65 families (about 60% of the regional flora in the east of the Russian Plain). Distribution of beetles over plant families is very non-uniform. Most of the specialized forms (78%) are associated with plants of 15 families, three of which (Asteraceae, Fabaceae, and Brassicaceae) include hosts of more than onethird of the beetle species (37%). Monophages and narrow oligophages are recorded on 201 genera of plants from 59 families. Polyphagous species are recorded on plants of 58 families. The specific features of the distribution of phytophagous beetles over host plants (as compared to other insects) is a high fraction of species developing on coenophobes (particularly those of the family Brassicaceae) typical of the pioneer stages of successions with sparse herbaceous cover, and a small number of species associated with grasses and sedges. These features are most conspicuous in the fauna of Curculionidae.