حسین مددی

Competition as one of the most common interactions, plays an important role in the size, structure, and stability of insect communities and has been used as a strategy for determining the fitness of biological control agents . Offsprings of the braconid wasp, Habrobracon hebetor Say as a gregarious idiobiont ectoparasitoid is expected to be involved in a competition race which its outcome influences many aspects of H. hebetor biological traits. In this research, the cold storage of pupae and adults of H. hebetor in seven competitive levels at four temperatures (2, 4, 6, and 8 Cº) and for a period of 3, 7, 10, 14, 21, and 30 days investigated. Each treatment included three replicates which each replicate included 100 individuals. The results showed that adults were more resistant than pupae to low temperatures and with increasing competition levels, the resistance of wasps to lower temperatures decreased, as the lowest mortality percentage occurred at 8 Cº. Moreover, the adults were more resistant to low temperatures than pupae which regarding exposure of adults to low temperatures during winter was predictable. Accordingly, none of the pupae survived after 30 days at 8 C º although, the highest and lowest number of survived adults were recorded at the competition level of 1 and 12 as 52.12 ±3.6 and 33.6 ± 1.2 individuals confirming the negative effect of competition on cold storage of this parasitoid species.