Diane Shakes shakes her head. A trisexual arrangement is really not so different. And Shakes points out that hermaphroditism has a rich, varied and distinguished place in natural history. Other organisms display sequential hermaphroditism, she said. Oysters and other shellfish change from male to female as they age. She and her collaborators have been examining Auanema rhodensis, a species of nematode that brings a completely different take to hermaphroditism. Their bodies look like a female, but they make both eggs and sperm.

By Laura Spinney. MANY parasites interfere with the reproductive systems of their hosts to ensure their own survival. But an American entomologist has found a nematode worm that induces its male hosts to change sex. The remaining 35 per cent showed different combinations of male, female and intersex features Proceedings of the Royal Society of London B, vol , p Parasitised male flies adopt female flight patterns and mock egg-depositing behaviour, which is what the nematode wants, says Vance.

January 18, Diane Shakes shakes her head. A trisexual arrangement is really not so different. Three sexes—male, female and hermaphrodite—are "part of the plan" for many organisms.