Fig. 8: The proposed model of decreased oviposition in response to young female wasps.

Young female wasps have a stronger search performance than old female wasps. When flies see their young parasitic wasps, they present an antiparasitoid behavior to lay fewer eggs in response to visual perception through LC4 visual projection neurons. This oviposition depression is induced by the downregulation of the expression of Tdc2 and Tβh in the ventral nerve cord, which in turn leads to the dramatic reduction of octopamine (OA). Then, the dysfunction of mature follicle trimming and rupture mediated by low levels of OA neuronal activity results in ovulation defects and a sharp decline in the oviposition rate.