Genetic link discovered for redback spider's fatal mating somersault

A University of Hamburg team investigated why male redback spiders deliberately somersault onto the jaws of females, a ritual that ends in sexual cannibalism. By breeding male redbacks with female katipō, a close relative that lacks the behavior, they raised hybrid males and recorded 104 mating events using infrared cameras. Roughly 50 % of the hybrids executed the fatal somersault, allowing researchers to infer that this trait is carried on a sex chromosome, whereas the abdominal constriction did not follow the same inheritance pattern.

Commentators noted the study shows how complex mating strategies can arise from simple genetic mechanisms and may evolve independently. The findings provide a genetic framework for future investigations into spider behavior and evolution.