EFFECTS OF STATIONARY PHOTOPERIOD ON REPRODUCTIVE DIAPAUSE, NYMPHAL GROWTH, FEEDING AND DIGESTIVE PHYSIOLOGY OF EYSARCORIS-LEWISI DISTANT (HETEROPTERA, PENTATOMIDAE)

In Eysarcoris lewisi DISTANT, the critical photoperiod for reproductive diapause was between 14L-10D and 16L-8D. The total nymphal period was significantly longer under 16L-8D than under 12L-12D and 14L-10D. The age-specific food consumption in the 5th instar nymph was different between the 12L-12D and 16L-8D groups. The total food consumption of the female 5th instar was greater in the 16L-8D group than in the 12L-12D group. Weights of the male nymphs and adults were not different among three photoperiodic groups, while those of the female 5th instar and adults were significantly greater in the 14L-10D and 16L-8D groups than in the 12L-12D group. During the 5th instar, amylase and invertase activities in the midgut were higher in the 16L-8D group than in the 12L-12D group, whereas acid phosphatase activity was higher in the latter than in the former.