Biologies of Three Species of Alydus1 in Wisconsin2

Alydus consperus Montandon, A. eurinus (Say), and A. pilosulus Herrich-Schaeffer overwintered in the egg stage and had 2 complete generations a year in southern Wisconsin. Nymphs began appearing in May, and adults could be collected until November. A. eurinus was the commonest species; A. conspersus was less common; A. pilosulus was uncommon. These bugs fed on a variety of legume seeds, including Baptisia leucantha T. & G., B. leucophaea Nutt., and Lespedeza capitata Michx., as well as on a nonlegume seed, Ceanothus americanus L. Two immature nematode parasites (Hexamermis) were obtained, each from an A. eurinus female. The laboratory biologies of the 3 species were very similar. Eggs hatched either after a short incubation period or after a period of diapause. The external characteristics of eggs were recorded. Head capsules of exuviae of the 5 instars were measured, and no overlapping was found between stages within each species. The use of spittle during cleaning was noted, and also the feeding of nymphs on eggs.