Flight and Fecundity of Colorado Potato Beetles (Coleoptera: Chrysomelidae) Fed on Different Diets

Abstract

Overwintered and summer generation adult female Colorado potato beetles, Leptinotarsa decemlineata (Say), were reared on 8 different diets (7 plant species and no food) for 30 d, during which time individual fecundity and flight mill performance were measured. Diet did not affect survival of overwintered females, but strongly affected survival of the newly eclosed summer generation. Fecundity was related positively for both generations to larval success on the different plant species. Tethered flight was greatest amongst starved overwintered females and generally greater in the overwintered generation than in the summer generation. Across treatments, total flight duration was related positively to fecundity for summer generation females; in contrast, it was related negatively to fecundity for the overwintered generation. However, there was no relationship between flight and fecundity within any of the treatments in either generation. Flight was greatest on days 3–6 for overwintered females, peaking later after eclosion for the summer generation, and continuing throughout the 30 d in at least some individuals. Flight was greater for summer generation females with greater emergence weight, and for overwintered females which emerged earlier. Among females nearer to death, or smaller females of the summer generation, reproduction took precedence over flight. The temporal patterns of fecundity and flight in female L. decemlineata constitute a flexible life history, which seems to represent an adaptation against disappearance of host plants when this risk is highest.