It has been shown previously that males of Heliothis virescens transfer juvenile hormone I (JH I) and juvenile hormone II (JH II) to the females, during copulation. The role of this transferred juvenile hormone is unknown. We hypothesize that this transferred juvenile hormone indirectly triggers oocyte chorionation.
To test this hypothesis we injected JH I and JH II at doses varying between 0.001 and 0.01 micrograms/insect into normal virgin females, at an age when they are likely to mate (24h of age). Numbers of chorionated oocytes were counted at 48h after injection.
In these experiments, 0.05 micrograms/insect of JH I stimulated oocyte chorionation in virgin females. However, the same dose had no effect on oocyte development if injected into decapitated females. The retrocerebral complex seems to be necessary for transmission of the signal from JH I to oocytes.
Our results suggest that JH I transferred from male to female during copulation may serve as a humoral factor signaling the retrocerebral complex that mating has occurred. Currently we are examining the endocrine background and its effect on response to JH I injections by virgin females of H. virescens.
Species 1: Lepidoptera Noctuidae Heliothis virescens (tobacco budworm)
Keywords: JH transfer, mating
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