Starting after 0.5-1 hours after mature populations were shifted back to room temperature from a 1 hour 37^oC heat shock transformant males exhibit homosexual courtship behaviour. The sexual behaviour of transformant females is indistinguishable from wild type. The inseminated females form clusters to avoid the rigorous male courtship activity. Virgins copulated with males before joining the female clusters. Female presence is not required for the male homosexual courtship activity. Non heat-induced male transformants also exhibit homosexual courtship behaviour suggesting the Hsp70 cis element may be activated by additional factors.