The presence of a male-killing bacterium in populations of Hypolimnas bolina butterflies affects the mating system. Contrarily to expectations, the reduction of the number of males incites the females to mate more often and with more partners.
A study at UCL (University College London) finds that a high-prevalence of male-killing bacteria active in many species of insect including the butterfly, actually increases female promiscuity and male fatigue.
