Experiments on Choice of Substrata by Spirorbis Larvae (Serpulidae)

Abstract

1. Spirorbis boreatis occurs typically on Fucus serratus, S. corallinae on Corallina officinalis and S. tridentatus on rocks and stones. 2. Laboratory experiments showed that the larvae of each species select the substratum on which the species typically occurs, the substrata of the other two species and a variety of other substrata being either less favourable or very unfavourable. 3. Larvae of S. borealis tend to be geopositive and photopositive when settling. Those of S. tridentatus are geopositive but overridingly photonegative, which explains the natural occurrence of this species in dimly lit places