Effects of Starvation, Copulation, and Insemination on Oocyte Growth and Oviposition by Periplaneta americana (Dictyoptera: Blattidae)

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Abstract
Isolated within 8 h after adult ecdysis, and kept on a diet of dog chow at 27 to 29°C with a LD 12:12 photoperiod for 30 days, nearly all Periplaneta americana (L.) virgin females produced one ootheca, and 35% produced two or three. Only ca. 30% of virgin females starved under these conditions oviposited, and each produced but one ootheca. After 8 days of isolation and starvation ca. 50% of the cockroaches copulated, and all that were inseminated produced one, occasionally two, oothecae containing a reduced number of fertile oocytes. Removing the spermatophore from the starved female before sperm had entered the spermatheca reduced the growth rate and production of oocytes, and delayed the onset of oviposition. Oocyte production by isolated, fed females was greatly enhanced after they had copulated, and, as with isolated, starved females, this was prevented by early removal of the spermatophore. Furthermore, neither group of females showed normally accelerated oocyte growth after copulating with castrated males. Spermatophores from these males lacked sperm, but were normal in shape and size, and they remained attached to the spermathecal nipple of the female for the usual 2 or 3 days. Unlike the condition reported for viviparous and ovoviviparous cockroaches, the major copulatory stimulus for oocyte growth seems not to be from sensoria in the bursa copulatrix, but follows deposition of sperm or other seminal components.