INFLUENCE OF PHASE POLYMORPHISM ON THE MORPHOMETRIC AND PHYSIOLOGICALPROCESSES IN PREPARATION FOR INSECT MIGRATION

Phase polymorphism is a density-dependent transformation in the behavi or, morphology and physiology of some migratory insects, such as the v elvetbean caterpillar, Anticarsia gemmatalis Hubner (Lepidoptera:Noctu idae). Wet and dry weight, wing loading ratio, carbohydrate and lipid utilization during flight, and the hyperlipemic response to extracts o f the corpora cardiaca (CC) were examined in A. gemmatalis adults with respect to larval population density and phase. Black phase adults fr om crowded, black larvae had lower wet and dry weights, whole body car bohydrate and lipid weights, and wing loading ratios than green phase adults from uncrowded, green larvae. When both adult phases were flown for 6 h, black phase adults used approximately 50% less lipid and car bohydrate than green phase adults. Elevation of the hemolymph lipid co ncentration (hyperlipemia) in A. gemmatalis adults is dependent on the dose of CC extract injected. Hyperlipemic responses of black phase ad ults were approximately two times greater than green phase adults. The role of phase polymorphism in the preconditioning of adult A. gemmata lis for migration is discussed.