Movement and oviposition of Ephestia cautella (Walker) and Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae) of different ages in response to seasonal light changes

Abstract

Movement and oviposition of two species of stored product insect pests, Ephestia cautella (Walker) and Plodia interpunctella (Hübner), were studied under natural day–night cycles for 4-day periods through four seasons and under continuous darkness (DD) and continuous light (LL) for one 4-day period. Both sexes of the two moth species showed initial movement peaks in the early evening in all four seasons. Oviposition peaks corresponded with the movement peaks. The main difference between the two species was that E. cautella, but not P. interpunctella, showed a second movement peak before dawn. In winter, however, E. cautella did not show a second movement or oviposition peak. Under LL and DD conditions, both species, regardless of sex, showed erratic movement and oviposition patterns without any discernible peaks. The response of P. interpunctella kept at LL, however, was significantly different (P < 0.01) from that obtained under DD conditions. Movement of both species regardless of sex increased with age and their patterns became more irregular.