Nutritive stress effects on growth and digestive physiology of Lymantria dispar larvae

Summary: The effects of parental and offspring diet on larval growth, food consumption and utilization, and activities of three digestive enzymes (a-amylase, trypsin, leucine aminopeptidase) were examined in extremely polyphagous insect, the gypsy moth (Lymantria dispar). In parental generation, gypsy moth larvae were reared on oak (Quercus cerris) leaves as optimal host or beech (Fagus silvatica) leaves which contains flavonoids and alkaloids. In offspring generation, after molting into the 4 th instar, they were either switched from oak to beech or remained on oak leaves. Decreased growth and food utilization efficiency, increased assimilation efficiency and activities of a-amylase and trypsin were recorded in larvae switched to beech leaves. Significant parental effects were demonstrated for fourth instar duration, weight of fifth instar larvae and specific activity of leucine aminopeptidase. Physiological, ecological and evolutionary context of the obtained results were stressed in the present paper.