Sublethal and transgenerational effects of insecticides in developing Trichogramma galloi (Hymenoptera: Trichogrammatidae)

Abstract

This study assessed the transgenerational effects of insecticides in developing Trichogramma galloi (Hymenoptera: Trichogrammatidae). Laboratory bioassays were performed in which five insecticides were sprayed on egg-larval, pre-pupal and pupal stages of the parasitoid. The interaction between insecticides and development stages of the parasitoid was not significant for the rate of F0 emergence. All insecticides significantly reduced the emergence of wasps, with the lowest emergence observed when they were applied to the pupal stage. For the sex ratio, only spinosad applied to the pre-pupal stage and triflumuron applied on the egg-larval and pre-pupal stages did not differ from the controls. Triflumuron applied to pre-pupae did not lead to any difference in the parasitism rate of the treated generation (F0) when compared to the control. There were no significant differences among survival curves for females of F0 when all insecticides were sprayed on the egg-larval stage. Both concentrations of lambda-cyhalothrin + thiamethoxam reduced female pre-pupal survival, and all treatments reduced female pupal survival. In addition, we observed a transgenerational effect of the insecticides on emergence and sex ratio of next generation (F1). Lambda-cyhalothrin + thiamethoxam (Min) applied to the pre-pupae and pupae, the maximum rate of the same insecticides applied to the egg-larvae and pre-pupae, and spinosad applied to pre-pupae all significantly reduced the adults emergence of T. galloi F1 generation. Only triflumuron did not alter the F1 sex ratio. These bioassays provide a basis for better understanding the effects of insecticide use on beneficial parasitoids.

Transgenerational interactions between pesticide exposure and warming in a vector mosquito

“…Together, our results underscore the importance of considering transgenerational plasticity not only when assessing the impact of warming (e.g., Donelson et al., ; Shama et al., ; Veilleux et al., ) and of pollutants (e.g., Costa et al., ; Pölkki et al., ; Schultz et al., ), but also when considering the impact of pollutants in a warming world. Our results thereby highlight the importance of integrating the emerging views of multistressor studies (Liess et al., ; Stoks, Geerts, & De Meester, ) and studies on transgenerational plasticity (Donelson et al., ; Guillaume et al., ) to understand the fate of species under global change.…”

Residual toxicity of insecticides used in Tunisian citrus orchards on the imported parasitoid Diachasmimorpha longicaudata (Hymenoptera: Braconidae): Implications for IPM program of Ceratitis capitata (Diptera: Tephritidae)

“…Even if we have classified both as slightly harmful for D. longicaudata (IOBC class 2) as in other risk assessment studies (Stark et al, 2004), opinions are still divergent about their compatibility with many biocontrol agents of other plant pests, especially parasitoids with emphasis on its possible trans-generational sublethal side effects (Bueno & Freitas, 2004;Biondi et al, 2012bBiondi et al, , 2013Costa et al, 2014;Abbes et al, 2015). As for the precedent substance, more research is required to determine the sublethal side effects on D. longicaudata.…”

Morphometry, allometry, and fluctuating asymmetry of egg parasitoid Trichogramma pretiosum under insecticide influence

“…Furthermore, studies focusing on transgenerational effects caused by insecticides on morphological traits would be necessary to better understand their effects in the long term. Negative transgenerational effects on longevity, parasitism rate, and emergence rate have already been reported (Costa et al, 2014). Finally, we suggest that morphometric tools provide important information on the development of T. pretiosum, and show potential use in the quality control of parasitoids, as their size is extremely important for the success of biological control.…”

“…We found no relation between wing and tibia vs. total length of the insect, and no fluctuating asymmetry. Negative transgenerational effects on longevity, parasitism rate, and emergence rate have already been reported (Costa et al, 2014). Additionally, Bennett & Hoffmann (1998) also considered fluctuating asymmetry a good tool to evaluate parasitoids, after evaluating Trichogramma carverae Oatman & Pinto females and finding that individuals with lower asymmetry degree in the anterior wings are more likely to find hosts.…”