From Nature:
Ever think your spouse is turning you grey before your time? Well things are very different for a beetle being studied by Swedish evolutionary biologists. They have found that some male bean weevils can slow down the ageing process in their mates simply by having sex with them. Female weevils (Acanthoscelides obtectus) live longer when mated with males that have been bred to reproduce later in life, report researchers at Uppsala University. By supplying a cocktail of age-defying chemicals with their sperm, the males stop their mates dying off before they have had the chance to produce a large family. “The males are promoting their own selfish interests by being the good guys in this case,” explains Göran Arnqvist, a member of the study team. “It benefits males if their mates live longer.”
More here.