Reduced Densities of Ectosymbiotic Worms (Annelida: Branchiobdellida) on Reproducing Female Crayfish

Abstract

Cleaning symbioses provide net benefits by improving each partner's fitness. Ectosymbiotic Cambarincola spp. (branchiobdellidans) can increase growth and survival of Cambarus chasmodactylus (New River Crayfish), but the nature of the symbiosis might change with female reproductive state because brooding offspring (eggs, young) and worms inhabit the same surfaces. Here, we present the results of field surveys that examined whether the number and location of branchiobdellidans on New River Crayfish varies as a function of female crayfish reproductive state. Reproducing female New River Crayfish had fewer total worms, an absence of cocoons, and a relatively greater proportion of worms on lateral body surfaces than non-reproducing crayfish. The altered distribution and reduced abundance of worms suggest that the symbiosis changes with female reproductive status, but additional experiments will be needed to identify the mechanism responsible.