An exception to the rule that there are no marine insects

INSECTS DOMINATECONICETCENPAT dry land. About 1m species have been described, more than twice as many as all other multicellular animal species, terrestrial and marine, put together. Several times that number are reckoned to await discovery. The oceans, though, are mostly insect-free. A few skate over the surface, but none dive willingly below the waves.At least, that was the consensus until recently. But Soledad Leonardi at - in Argentina and Claudio Lazzari at the University of Tours, in France, have found an exception: the 13 species of lice that latch onto seals. That seals have lice is not news. But Dr Leonardi and Dr Lazzari have shown that, contrary to previous belief, these passengers do not abandon ship, as it were, and remain on dry land when the seals go swimming. Instead, they cling on and brave not only the hostile, saline chemistry of seawater, but also the tremendous pressures imposed when their hosts dive to depths of several hundred metres in search of prey.