The relationship between crop size and egg production in Rhodnius prolixus

Abstract

Earlier work showed that the number of eggs produced by a virgin female is smaller than that produced by a mated female. The current paper shows that this results not from a difference in rates of egg production, but from the operation of the same linear rate for different times. Denervating the corpus allatum in virgin females extends the time over which the same rate of egg production operates, thus indicating that the inhibition of egg production in virgin females results from a nervous inhibition of the corpus allatum. The initial rate of emptying of the crop is also approximately linear in both virgin and mated females. Later, crop emptying slows in virgins and remains linear in mated females. When these relationships are disturbed by plugging the anus of females before feeding, the rate of crop emptying in virgins more closely resembles that in mated females, and the difference in egg production between mated and virgin females disappears. These results are put into the context of a hypothesis which predicts that the degree of distension of the crop is an important determinant of the length of time that the corpus allatum remains active.