Seasonal Field Analyses of Fat Content, Live Weight, Dry Weight and Water Content of the Aphidophagous Scymnodes Lividigaster (Mulsant) and Mycophagous Leptothea Galbula (Mulsant) (Coleoptera: Coccinellidae).

Abstract

Over 36 and 24 months, respectively, both the aphidophagous Scymnodes lividigaster (Muls.) and the mycophagous Leptothea galbula (Muls.) accumulated fat before periods of dormancy, but contained little fat after dormancy and during breeding. Over the whole period, there were no significant differences between sexes or between years in either species, except that dormant females contained significantly more fat than males, and that during breeding males of S. lividigaster contained significantly more fat than females. Subjective assessment of fat reserves gave the same results as did quantitative analysis. Live and dry weights of females were higher during breeding and dormancy than after dormancy; live weights of females were higher than those of males. Water content was lower during dormancy than during breeding. In L. galbula, seasonal changes were similar in a dry and a well watered habitat; any differences appeared related to a higher survival rate in females compared with males, especially in the poorer habitat. In S. lividigaster, seasonal changes in fat content were negatively related to changes in abundance of an essential prey species.