EFFECT OF MALE AND FEMALE AGE ON THE MATING SUCCESS OF THE OBLIQUEBANDED LEAFROLLER CHORISTONEURA-ROSACEANA (LEPIDOPTERA, TORTRICIDAE) UNDER DIFFERENT ECOLOGICAL CONDITIONS

The present study was undertaken to test the hypothesis that male and female age, as well as temperature, can affect the mating success of C horistoneura rosaceana, given the role that these two factors play in the pheromone biology of this species. In the laboratory, the mating s uccess of females generally declined linearly with age, whereas in mal es, it increased during the first 3 days and then decreased. The decli ne in female mating success was more pronounced under warm than cool t hermocycles, while the changes observed in males were greater under fl uctuating than constant temperature regimes. The onset time of mating was unaffected by male age, however, older females always mated earlie r than younger ones, with the advance being more pronounced at cool th an warm temperatures. Similar results were also obtained under field c onditions. When a single 3-day-old male was provided with 0-, 3-, and 5-day-old females simultaneously, older females obtained mates signifi cantly more often than younger individuals at all temperatures, indica ting that calling earlier may afford a reproductive advantage to older females. At both constant temperatures, the time spent mating was lon ger in older than in younger females, but not under fluctuating thermo cycles. Very young and very old males generally spent more time in cop ula than middle-aged individuals both at constant temperatures and und er the warm thermocycle. Under the cool thermocycle, the duration of m ating was considerably prolonged at all ages, which could increase the risk of predation.