Frisky female fruit flies become more aggressive after sex

Female fruit flies start headbutting each other after mating, becoming significantly more aggressive and intolerant Oxford University research has revealed. Female fruit flies' levels of aggression soar after sex, when a variety of proteins, which flow freely in semen, stimulate dramatic behavioural and physiological changes in females. Other changes include increased ovulation, rejecting male advances and loss of interest in sex. Increased post coital levels of aggression may have wider in direct implications on female competition. Studies in many species have shown an association between increased levels of aggression in females, egg laying and reproduction. Protecting and providing for offspring is often identified as the main motivation for this behaviour. The factors at play in the reproductive process, that trigger such dramatic behavioural changes, have until now, been less clearly understood.