The influence of larval phase on metabolic reserves, fecundity and lifespan of the african armyworm moth, Spodoptera exempta (Walker) (Lepidoptera: Noctuidae)

Abstract

AbstractSpodoptera exempta (Walker), in common with several noctuid moths, exhibits a density-dependent phase polyphenism. The abdominal glyceride contents of both sexes at emergence were 2·5 to 6·1 times greater in the gregaria than in the solitaria phase moths. Abdominal and thoracic total protein levels, haemolymph total protein, glyceride and carbohydrate, and the relative quantities of tri-, di- and monoglycerides were comparable in the two forms. Weight-related fecundity was strongly influenced by larval phase. Females from solitaria larvae produced approximately half the numbers of eggs laid by those reared in crowded conditions, but this difference was only evident in moths allowed distilled water. Moths having access to sucrose laid comparable numbers of eggs, irrespective of phase. There were no differences in the levels of metabolic reserves in the eggs. Differences in glyceride content, preoviposition period, fecundity and lifespan were apparent between laboratory strains. The implications of these differences for migratory flight and reproduction in the field are discussed.