Influence of Diet on the Density-Dependent Phase Polymorphism of Velvetbean Caterpillars (Lepidoptera: Noctuidae)

Velvetbean caterpillars, Anticarsia gemmatalis Hübner, were reared at different larval densities on meridic diets containing different amounts of foliage. The degree of dark body color and yellow to orange head color was highest in larvae reared crowded and on meridic diets containing the most dried soybean foliage in artificial diet or consisting completely of fresh kudzu or soybean foliage. No body color change from green was observed in solitary larvae reared on the same diets as crowded larvae. Larvae developed most rapidly on meridic diets containing the lowest and highest amounts of foliage. On all meridic diets tested, solitary larvae developed to the pupal stage at least 1 d faster than crowded larvae. Larvae reared on fresh foliage developed into pupae and adults that weighed the least.