Variations in body length, weight, fat content and survival in Coccinella septempunctata at different hibernation sites

Abstract

AbstractAdults of Coccinella septempunctata L. (Coleoptera; Coccinellidae) were sampled in four overwintering sites: one in England and three at different altitudes in the Czech Republic (350–1420 m above sea level) in autumn 1992 and spring 1993. Body length, dry weight and fat weight were measured. There were significant differences in body length between sampling sites in spring 1993, but not in autumn 1992. The average sex ratio (♀) in all samples was 1:0.60 in 1992 and 1:0.72 in 1993. Females were significantly larger and heavier, and contained more fat than males in both sampling periods. Dry weight and fat weight were positively correlated to body length at all sampling sites except at Ruzyne, in the Czech Republic. Adults hibernating at higher altitudes and away from their breeding and feeding habitats had significantly more fat than those hibernating at lower altitudes. Fat reserves were reduced by 30% during the hibernation at the top of the Krkonose mountain, in the Czech Republic, where temperatures were much lower, but more than half of the fat reserves were consumed during the overwintering period at the other sampling sites. The significance of body length and fat reserves in relation to adult hibernation sites and overwintering survival is discussed.