Antibiotics cause parthenogenetic Trichogramma (Hymenoptera/Trichogrammatidae) to revert to sex

Completely parthenogenetic Trichogramma wasps can be rendered permanently bisexual by treatment with three different antibiotics or high temperatures. The evidence strongly suggests that maternally inherited microorganisms cause parthenogenesis in these wasps. Theories predict female-biased sex ratio in offspring under the influence of maternally inherited symbionts, but extreme sex ratios of 100% females were never considered because the lack of males would prevent the host's reproduction.