Sex and the single copepod

摘要

Consider the ocean as a watery discotheque, thronged with tiny organisms — in particular, copepod crustaceans, dominant constituents of the zooplankton, and desperate to find mates. With an estimated one hundred billion trillion potential partners to choose from, it might seem that copepod mating is trouble free, even given the need to.find a partner of the same species, opposite sex and ready to reproduce. As described by papers in a special issue of Philosophical Transactions of the Royal Society, however, that isn't so. The reasons are outlined in the preface (by G. Boxshall). The world's oceans consist of 1,347 million km~3 of open pelagic water-column, and each cubic metre of sea water may contain just a few copepods. These creatures range in size from just 0.5 mm to 10 mm, and they function at low Reynold's numbers — that is, viscous forces dominate their environment, and copepod movement in water is a bit like human movement in treacle. So it might seem that copepods are completely at the mercy of water movements.