The effects of mating, age at mating, and plant stimuli, on the lifetime fecundity and fertility of the generalist herbivore Epiphyas postvittana

The effects of mating, age at mating, the presence or absence of a plant le af, and the deprivation of a suitable ovipositional substrate during when t he first ovipositional bout after mating would normally take place, on the lifetime fecundity and fertility (percentage of fertile eggs laid) of femal e Epiphyas postvittana were investigated. Mating had a significant effect o n lifetime fecundity, with mated females laying 2.5 times more eggs than vi rgin females. Age at mating had a significant effect on both fecundity and fertility, both declining with increasing age when the female was mated. In the presence of a leaf of C. japonica, mated females had a greater lifetim e fecundity than when no leaf was present; females in the presence of a C. japonica leaf consistently laid more eggs each day during the first 4-6 day s after mating than females without a leaf. When females were deprived of a suitable ovipositional substrate, for the first 22 h after mating, they we re significantly less fecund over their lifetime than were control females. Finally, in no-choice tests with three plants of different acceptability t o females, the fecundity of females differed in the order C. japonica > Urt ica ferox > Tibouchina multiflora. This different fecundity appeared to be inversely related to the pubescence of the leaves, suggesting that leaf tex ture may be a suitable antixenotic resistance factor for crops to be protec ted from this insect. These results suggest that strategies whereby mating is delayed or oviposition reduced within a critical period after mating, ma y result in significant reductions in pest populations.