Substrate selection of Christmas tree worms (Spirobranchusspp.) in the Gulf of Eilat, Red Sea

Abstract

Christmas tree worms (Spirobranchusspp.) are prominent sessile organisms inhabiting hermatypic corals in tropical and sub-tropical reefs. Until recently, most of the largerSpirobranchusspecies were considered to be in obligatory associations with live hermatypic corals. However, recent studies indicate that someSpirobranchusspecies can build tubes on artificial substrate as well and that others may show preferences for using specific species of corals and hydrozoans as substrates. In the present study, we conducted a survey ofSpirobranchusspp. substrate preference in the Gulf of Eilat. We found seven morphotaxa ofSpirobranchus, of which two may be a single new species. We show thatSpirobranchustaxa differ not only in their morphology, but also in their substrate use. Our results demonstrate that the ecological niche ofSpirobranchusis species-specific, and a putative innate preference exists for some substrates.