The effect of the age of female Nasonia vitripennis (Walker) (Hymenoptera, Pteromalidae) upon the incidence of larval diapause

Abstract

A study of the incidence of diapause in the progeny of single females of Nasonia vitripennis has been made throughout their lives. Although individual results are variable, it is shown that as the maternal generation becomes more senile, a greater proportion of the progeny enter diapause at the end of the fourth larval instar. In many females, the change-over from the production of non-diapause to diapause offspring is extremely sudden. A few females are shown to have the opposite trend, producing more diapause larvae at the beginning of life. An overall comparison of the observed and expected frequencies of diapause in the first and second halves of the life-span, however, is highle significant.