EMERGENCE RHYTHMS AND PROTANDRY IN RELATION TO DAILY PATTERNS OF LOCOMOTOR-ACTIVITY IN TRICHOGRAMMA SPECIES

In insect parasitoids, the mating structure of the population depends on the emergence pattern of adults and on their behaviour after emerge nce. In order to study some aspects of these characteristics in four s pecies of egg parasitoid of the genus Trichogramma, laboratory experim ents using automatic video analysis are performed. Adult emergence is concentrated in the morning, with an earlier time for males. The varia bility of the time of emergence is under genetic control. The relation ships between the emergence pattern and the locomotor activity are con sidered by measuring individually: first, the delay between the emerge nce and the first locomotion which is significantly greater in females than in males and, second, the activity of newly emerged males, which is maximum at the time of the emergence of females. The locomotor act ivity is influenced by mating; mated females are much more active than virgin ones, mated males are less active than virgin ones. The adapti ve values of the rhythmicity of emergence and of protandry are discuss ed together with their relationship with the patterns of locomotor act ivity. The results are also considered with respect to mating strategi es in insect parasitoids; they actually support the hypothesis of mati ng occurring principally among individuals native to the same host pat ch in Trichogramma species.