SPERM CHEMOTAXIS IN OIKOPLEURA DIOICA FOL, 1872 (UROCHORDATA: LARVACEA).

An alcohol extract of unfertilized eggs of the larvacean, Oikopleura dioica, can attract sperm over a distance of at least 80 µm from an artificial source. The sperm, which normally swim in wide circles or straight lines, alter their path to form small loops between straight or slightly curved segments directed up the gradient. During the first loop, the velocity of sperm increases 50%.