Grandmother’s chemical legacy of pesticide exposure: bi-generational effects and acclimation in a model invertebrate

Man-made chemicals are a significant contributor to the ongoing deterioration of ecosystems. Currently, risk assessment of these chemicals is based on observations in a single generation of animals, despite potential adverse intergenerational effects. Here, we investigate the effect of the fungicide prochloraz across three generations of Daphnia magna. We studied both the effects of continuous exposure over all generations and the effects of first-generation (F0) exposure on two subsequent, non-exposed, generations. Effects at different levels of biological organization were monitored. Acclimation to prochloraz was found after continuous exposure. Following F0-exposure, non-exposed F1-offspring showed no significant effects. However, in the F2 animals, several parameters differed significantly from controls. A direct association between grandmaternal effects and toxic mode of action of prochloraz was found, showing that chemicals can be harmful not only to the exposed generation, but also to subsequent generations and that effects may even skip a generation.

Effects of Experience on Subsequent Feeding or Oviposition Preference in Musca domestica (Diptera: Muscidae) and Chrysomya megacephala (Diptera: Calliphoridae)

Objectives of this research were to evaluate the effect of larval experience on feeding preference of larvae and the effect of larval and pupal experience on oviposition preference of females in Musca domestica L. and Chrysomya megacephala F. Dietary experience from hatch to test significantly influenced feeding preference of the second-instar larvae in M. domestica (P < 0.01), but did not in C. megacephala. The larval dietary and pupal experience did not change the oviposition preference of C. megacephala, and experienced gravid females laid all of their eggs on pork muscle. Larval feeding regimen had no effect on oviposition preference of subsequent females in M. domestica. However, the pupal experience in M. domestica significantly influenced the oviposition preference of subsequent females, and M. domestica females from pupae matured on wheat bran laid significantly more eggs on wheat bran than those that matured on pork muscle, or filter paper whether pupae were washed or not (P < 0.01). These results demonstrated that host-selection behavior in M. domestica was shaped by preimaginal experience according to the chemical legacy hypothesis.