Bioecologie de et parasites de [] dans le sud de la France

Cette étude porte sur différents aspects de la biologie de et, se développant sur, ravageur du Pin maritime: comportement parasitaire à l'égard de ce charançon, durée du développement, durée de la maturation sexuelle, espérance de vie des adultes, etc. Le cycle biologique de ces parasitoïdes est étudié ainsi que le problème de la coïncidence temporelle entre ces braconides et leur hôte dans le cas d'une forêt du sud de la France.This study shows that is an endophagous egg-larval parasitoid of. After hatching, the parasitoid larva develops in the larva until the host has formed the pupal chamber. Therefore the complete development of this wasp is conditioned by the speed of the host development. In suitable laboratory conditions (19°C) or in the forests of southern France during the summer, the development requires approximately 2 months but is slower when the temperature is lower as in winter. Consequently, on this braconid shows 2 generations a year, the 1st one emerging from April to the beginning of June and the 2nd one from the end of June up to mid-August. and are observed as ectoparasites mainly on the 2nd and 3rd stages of, occasionally on the 4th one. At 19°C, the complete development requires 1 month. In field conditions the emergences occur continuously from April to August but arise from 4 successive overlapping broods, the 1st one resulting from diapausing pupae that appear in September and overwinter until spring.Despite the plurivoltinism manifested by these 3 parasitoids, their population sizes have always remained low. The main factor responsible for this weak parasitization effect on is the unavailability of suitable host-stages when the females become able to oviposit, i.e. about 1 week after their emergence.