Nature 187, 345 (23 July 1960); doi:10.1038/187345a0

Prevention and Artificial Induction of the Imaginal Diapause in Coccinella 7-punctata L.

I. HODEK & J. ERKASOV

Entomological Institute, Czechoslovak Academy of Sciences, Prague.
Biological Faculty, Charles University, Prague.

BY field observations, dissections and analyses of field samples it was discovered that the female diapause in Coccinella 7-punctata L. (Col. : Coccinellidae) is connected with a gonotrophic dissociation, which is not the case in male individuals. After the induction of diapause the adults of both sexes accumulate reserves (fats and glycogen) ; afterwards they stop feeding and migrate towards the winter quarters. During this prehibernation accumulative feeding-period, the females remain sexually immature. On the other hand, for males the maturation of gonads is not such a strain on energy reserves ; both diapausing and active males rapidly reach maturity and only stop tissue activity in testicular follicles immediately before hibernation. At this period they have already accumulated sperm reserves in the seminal vesicles and encysted sperms in the testicular follicles. Already before hibernation they fertilize a part of the females, hibernating afterwards with sperm reserves in the spermatheca. In the spring the males renew their sexual activity long before the females. They fertilize females in the hibernating quarters. The ovaria mature later—only after feeding on the essential aphid food. During hibernation the fat reserves in both sexes are reduced to a half; the glycogen in males to one-fifth, in females to one-third.

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