Lernaeodiscus porcellanae turns control of the host into a fine art. After castration by the parasite, male crabs develop female characteristics in both anatomy and behavior, while females become even more feminized. The emerging externa then takes the same form and position as the crab's own egg mass... The crabs then treat the externa as their own brood. In other words, the parasite usurps all the complex care normally invested in the crab's own progeny.

Triumph of the Root-Heads, p. 368 - Leonardo's Mountain of Clams and the Diet of Worms (1998)