The Influence of Various Gramineae on Weight Gains of Postdiapause Adults of the Cereal Leaf Beetle, Oulema melanopa (Coleoptera: Chrysomelidae)1

Abstract

Hibernating beetles were field collected in September 1963 and were stored in a refrigerator, first at 40° and then at 32 °F. They were used in laboratory studies only after a sufficient time lapse (at least 30 days) to assure that diapause was broken. The beetles were weighed, then confined on different species of Gramineae, and were reweighed after 1 week and 2 weeks had passed. They accepted Hudson barley before Clintland 60 oats and fed on it slightly more; differences in feeding and acceptance between wheat and oats, and rye and oats, were not significant. They gained weight rapidly on barley, oats, wheat, or rye, and slowly on corn, but did not gain appreciably on tall fescue, Sudan grass, or orchard grass, though orchard grass was accepted as readily as oats. Their gain on a sorghum-Sudan hybrid was significantly lower than on oats. They lost weight on grain sorghum, giant foxtail, and pearl millet, and fed only slightly on these host plants. Their survival was high on all the small grains and on corn; moderate on orchard grass, tall fescue, and the sorghum-Sudan hybrid; and very low on grain sorghum, Sudan grass, and pearl millet.