Seasonal Distribution, Reproductive Diapause, and Parasitization of Three Nabis spp. 1 in Southern Arizona 2

Abstract

Nabis alternatus Parshley, N. americoferus Carayon, and N. capsiformis Germar usually diapaused from October through December in the Tucson and Mesa areas of southern Arizona, though in some years diapause started in September and lasted into February. The winter generation of N. alternatus was unique in experiencing a noticeable color change, but that generation of all 3 species appeared somewhat larger. The ratio of the sexes of all 3 species was ca. 1:1. Nabis alternatus was the predominant species in the Tucson area, N. americoferus was the predominant species in the Mesa area, and N. capsiformis occurred only in the Tucson area. Nabis alternatus and N. americoferus probably have 5 generations per year; all 3 species had 2 main peaks in population each year, one in May and one in November. Two species of tachinids, Hyalomya aldrichii Townsend and Leucostoma simplex (Fallen), commonly parasitized all 3 species. Nabis alternatus and N. americoferus females are rarely parasitized by Wesmaelia pendula Foerster.