Effects of Wolbachia symbiotic bacterium on some biological characteristics of Trichogramma brassicae in laboratory and cold storage conditions

In this research, the effect of the intracellular symbiotic Wolbachia bacteria on attack rate (a), handling time (Th) and emergence rate of Wolbachia infected asexual (A), natural bisexual (B) and cured bisexual by antibiotic (CB) strains of Trichogramma brassicae was studied under laboratory and cold storage conditions. The evaluation of functional response of the Trichogramma strains exposed to different densities of Ephestia kuehniella eggs revealed type II, and no significant difference was observed between the attack rate and their handling time. Based on the results of short-term cold storage, the hatching rate of all three populations reared at 20°C was higher than populations reared at 25°C, and statistically had a significant difference. However, in similar storage periods, the populations infected (A) and non-infected (B and CB) were in the same groups with no significant difference in terms of the emergence rate. According to the results of this study and previous findings, by providing optimal conditions for reproduction and maintenance of Wolbachia infected lines, the use of thelytokous Trichogramma wasps would be more economical compared with natural sexual populations, which is discussed in this article.