A Bilaterally Gynandromorphic Hypodynerus, and a Summary of Cytologic Origins of such Mosaic Hymenoptera. Biology of Eumenine Wasps, VI.

Abstract

A nearly perfectly divided, left (♂)-right (♀) gynandromorph of the Chilean eumenid wasp Hypodynefus tuberculiventris (Spin.) and a dissection of its terminal retracted abdominal segments and genitalia are described and illustrated. A table summarizes the morphology of the seven or eight other sexual mosaics recorded in the Eumeninae (Vespidae). Although female Hypodynerus average considerably larger than males, the approach to dimensional symmetry of the male and female halves probably reflects nearly equal growth per food unit (at not-extreme ranges of provisioning) of male and female wasps, and not a dominant influence of the female half. Indeed, as is usual for such mosaics although not invariably so, the male and female tissues of this wasp appear to have differentiated autonomously. The rarity of collection of such mosaics (frequency < 0.01%) grossly underestimates the frequency of the cytologic mishaps giving rise to them. The known errors of oocytic meiosis, of suppression of nuclear activity, and of fertilization leading to gynandromorphy are discussed; in aggregate their raw frequencies for Hymenoptera probably lie between 0.1% and 1.0% of all egg.