Species composition and relative abundance of coccinellidae (Coleoptera) in south central Nebraska field crops

Abstract

Species composition and relative abundance of adult Coccinellidae were monitored in field corn (Zea mays L.), grain sorghum (Sorghum bicolor L. Moench.), winter wheat (Triticum aestivum L.) and alfalfa (Medicago sativa L.) in south central Nebraska during 1992-1995. Two native coccinellids, Hippodamia convergens Guérin-Méneville and Coleomegilla maculata (DeGeer), were the most common species during all years and in all crops, comprising >77% of the individuals observed. Averaged over all years, H. convergens was the most common species in alfalfa and sorghum, and C. maculata was the most common species in corn and wheat. Other species collected included Coccinella septempunctata (L.), Hippodamia parenthesis (Say), Hippodamia tredecimpunctata tibialis (Say) and Cycloneda munda (Say). Although there was variation in species composition by crop and year there were no significant differences in species diversity as measured by the Berger-Parker species dominance index (d) and the Shannon-Weaver function (H). This information will help target future studies in conservation, augmentation and classical biological control involving coccinellids.