Effect of extirpation of median neurosecretory cells on reproduction in the female red cotton bug, Dysdercus cingulatus

Abstract

Extirpation of the cerebral neurosecretory cells of the pars intercerebralis of the red cotton bug, Dysdercus cingulatus, does not prevent maturation of the first batch of eggs in the female. However, vitellogenesis is visibly inhibited by the operation. There is considerable individual variation in the degree of inhibition of vitellogenesis in experimental animals. But in these experimental animals ovaries are shorter, their oöcytes smaller, the number of oöcytes undergoing vitellogenesis fewer: also the follicle cells and their nuclei are smaller. On the contrary, the protein concentration in the blood of experimental animals is higher but is subject to considerable variation and it appears to have no significance. It is concluded that the median neurosecretory cells stimulate vitellogenesis in this animal to a considerable extent.