| Abstrakt: |
Recent detections of adults of three previously common, native species of lady beetles [Coccinella novemnotata Herbst, Coccinella transversoguttata richardsoni Brown, and Adalia bipunctata (L.); Coleoptera: Coccinellidae] during surveys at several sites in western South Dakota and western Nebraska provided impetus for additional sampling of lady beetles in that region. The current study systematically sampled for lady beetles among three dominant habitats in the region in 2010 and 2011. Four techniques (sucrose-baited and nonbaited yellow sticky traps, sweepnetting, visual searches) sampled 4,036 adult and 830 larval coccinellids comprising 10 species. Coccinella septempunctata L., Hippodamia convergens Guerin-Meneville, Hippodamia parenthesis (Say), and Brachiacantha alhifrons (Say) were the most common species. C. novemnotata ranked fifth in abundance, with 94 sampled in small grains, 20 in alfalfa, and 5 in grassland pasture; 58 larval C. novemnotata were sampled primarily in small-grain fields. Abundance of C. novemnotata negatively correlated with proportion of vegetative cover in fields, whereas this characteristic did not correlate with abundances of H. convergens, H. parenthesis, and C. septempunctata. Abundance of these three species negatively correlated with vegetative species richness and diversity in fields, whereas C. novemnotata abundance was not related to these indices. Fourteen C. transversoguttata richardsoni, 30 C. novemnotata, and several other coccinellids were observed on roadside vegetation near sample fields. A. bipunctata was not sampled in this study. Results suggest that sparsely vegetated small-grain fields may favor reproducing populations of C. novemnotata in relatively arid areas of the north central United States. [ABSTRACT FROM AUTHOR] |
