Queen of Decay

Abstract

DEVELOPMENT Osedax (shown above) is a recently discovered annelid worm that, with a little help from endosymbiotic bacteria called Oceanospirillales, feeds on the bones of whales. However, whale carcasses are rare, and the diversity of Osedax species astonishing, so how these organisms persist and scatter is a conundrum. Rouse et al. have set out to elucidate the life-history peculiarities of worms feasting on whale carcasses planted at defined depths in Monterey Bay, California. Male worms are parasitic on females, and thus fertilization is guaranteed. Moreover the animals are highly fecund, with females devoting a large proportion of their body mass to ovary, whereas the male's somatic development is sidetracked into sperm production, possibly by signals from the females; under laboratory conditions, they seem to reproduce continuously. It appears that the metamorphosis of females from a swimming trochophore only occurs when the larvae encounter a carcass and have been infected with the endosymbiont. These tactics concur with the obvious ecological needs of these strange worms, but how long the larvae live, whether they have searching strategies, and how far they disperse are interesting questions that still await answers. — CA Mar. Biol. 10.1007/s00227-008-1091-z (2008).