VARIATIONS DURING THE GONOTROPHIC CYCLE IN THE TITER OF THE MYOTROPIC OVULATION HORMONE AND THE RESPONSE OF THE OVARIAN MUSCLES IN RHODNIUS-PROLIXUS

The response of the ovarian muscles to a standard preparation of the myotropic ovulation factor from identified neurosecretory cells in the brain of Rhodnius prolixus increases after feeding in both virgin and mated females. This increase is unaffected by removal of the neurosecretory cells and by increases imposed on the resting tension of the ovaries used in the bioassay. The hemolymph titer of the myotropic activity as determined by bioassay exhibits a peak after feeding in both mated and virgin females. A 2nd peak, corresponding both with the principal bout of ovulation/oviposition and with a corresponding peak in ovarian motility previously observed in vivo, is observed only in mated females. The changes in ovarian motility associated with ovulation in Rhodnius are a consequence primarily of variations in the hemolymph titer of the myotropic ovulation hormone from neurosecretory cells in the brain.