The Bisexuality of Uniparental Hymenoptera, a Function of the Environment

Abstract

Hymcnopteran spp. are of 2 sorts, those which reproduce biparentally, yielding uniparental [male][male] and occasionally uniparental [female][female], and those which reproduce uniparentally, usually yielding [female][female] although only [male][male] may be produced. The production of [male][male] or [female][female] apparently depends upon the nutrition and environmental temp. of the uniparental [female] larva. The thelytocous, or [female]-producing condition, seems to be associated with lower temps. than is the arrhenotocous, or [male]-producing. In some cases the 2 ovaries might possibly be of different types, thus yielding equal numbers of [male][male] and [female][female]. Observations on Habrolepis rouxi indicated that thelytoky usually results from a doubling of the chromosome number in the primary oogonia. Since uniparental reproduction is more common in the primitive Hymenoptera, it is believed that it is derived directly from biparental reproduction, in winch [male][male] are diploid. rather than from biparental reproduction, in which [male][male] are haploid. The conclusions reached by the author are based in part on new experimentation and also on a detailed consideration of the literature (53 citations).