Diet and abundance of the barber goby Elacatinus figaro on Brazilian marginal reefs: ecological predictors and reliance on cleaning interactions

Abstract

Cleaning behavior is a well-known example of trophic specialization that is widespread in marine organisms from both tropical and temperate ecosystems. Cleaner species can be more or less specialized in different aspects of cleaning interactions, and it is often assumed that the more specialized cleaners are, the more they rely on clients for food. However, cleaners can consume different items in different sites, and the factors influencing such variation are still poorly understood. Here, we investigated the diet and distribution of the barber goby Elacatinus figaro across marginal reefs of the Brazilian coast. We evaluated E. figaro’s reliance on cleaning interactions for food and asked whether its diet and abundance corresponded to the availability of ectoparasites and/or clients. The diet of E. figaro varied across sites, but ectoparasite reliance was similar and did not correspond to client’s infestation loads. Moreover, the density of E. figaro did not correlate with the density or richness of potential clients. These support the hypothesis that E. figaro is less reliant on cleaning interactions for food than other cleaning goby species and suggest a high feeding and behavioral plasticity in marginal reefs. This study also highlights that the current dichotomous classification scheme of dedicated versus facultative cleaners fails to capture the subtle nuances of cleaning behavior and should therefore be used with caution in future comparative studies.