Toxicity and Transgenerational Effects of Insecticides on Trichopria anastrephae (Hymenoptera: Diapriidae).

Abstract

Trichopria anastrephae Costa Lima, 1940 (Hymenoptera: Diapriidae) is a pupal endoparasitoid of Drosophila suzukii Matsumura, 1931 (Diptera: Drosophilidae) in Brazil. This species is of great agricultural importance and is almost exclusively managed by organophosphate, spinosyn, pyrethroid, neonicotinoid, and avermectin insecticides. However, frequent application of insecticides can have negative effects on the parasitoid. The objective of this study was to evaluate the lethal and transgenerational toxicity of five insecticides on T. anastrephae adults during the F0, F1, and F2 generations. Drosophila suzukii puparia were sprayed prior to their exposure to T. anastrephae for 24h. Parameters evaluated in generation F0 were mortality and rate of parasitism. After the emergence of the F1 generation, the emergence rate and sex ratio were analyzed. Then, pairs of parasitoids were selected from F1 and pupae; the host was offered to evaluate parasitism, emergence, and sex ratio of the F2 generation. In the F0 generation, malathion was the only insecticide that caused 100% mortality of adults of T. anastrephae. However, all insecticides tested affected the parasitism rate, being classified as moderately to slightly harmful. In F1, the emergence of T. anastrephae was also affected, making the insecticides moderately to slightly harmful. However, there were no significant differences in the sex ratio and parasitism rate or the parameters evaluated in F2, which means that all products were classified as harmless. These results are important for the development of Integrated Management programs for D. suzukii and for the conservation of natural populations of T. anastrephae in the field.