Vertical and temporal distribution of Coccinellidae (Coleoptera) in flightover an agricultural landscape

Twenty-one species of Coccinellidae were trapped in flight between 0.8 and 14.3 m from 1992 to 1995 in New Brunswick, Canada. Catches were larger at 0 .8 m, with a rapidly decreasing capture rate leading, on average, to more t han 50% of the catches at or below 3.8 m every year. The capture rate at 14 .3 m was lower than at any of the nine other levels. Hippodamia convergens Guerin-Meneville flights were distributed close to the ground, with more th an 50% of catches at 0.8 m, whereas Mulsantina hudsonica Casey flights were similar at all levels. The strong decreasing gradient of flight as a funct ion of height for Coccinellidae (-0.825) was strongly influenced by that of H. convergens (-1.809) and of Coccinella septempunctata L. (-0.921) and Co ccinella trifasciata perplexa Mulsant (-0.715). All other species had a slo pe of less than -0.5. The temporal distribution of flights was species spec ific, with maximum activity before the end of June for most, but this was n ot reflected in the frequency of catches for the entire family, which did n ot differ throughout the season, although they tended to be lower after mid -August. The weekly vertical flight distribution differed from the average distribution pattern only occasionally, probably during periods of long-dis tance dispersal. These profiles and known catches from a single trap locati on can be used to estimate dispersal activity at different heights.