Grazing fishes farm algae, and consume algae, detritus and sediment and consequently differentially modify benthic communities. Manipulations of cleaner fish Labroides dimidiatus on reefs show that cleaners affect fish abundance differently according to grazer functional group. Accordingly, whether reefs are grazed differently, with consequences for the benthos (fouling material tile −1 ), was tested using reefs kept free of L...

Aim We studied the underlying biotic and abiotic drivers of network patterns in marine cleaning mutualisms (species feeding upon ectoparasites and injured tissues of others) at large spatial scales. Location Eleven marine biogeographical provinces. Time period 1971–2018. Major taxa studied Reef fish and shrimps. Methods We combined field and literature data to test whether recurrent patterns in mutualistic networks (nestedness...

Diet analyses and observations of cleaning behaviour of two cleaner fishes revealed that Labroides bicolor fed more on client mucus, but Labroides dimidiatus fed more on ectoparasites, and that L. bicolor interacted with fewer species (36 species) compared with L. dimidiatus (44 species). The client species which contributed most to the dissimilarity between cleaner species were the dusky farmerfish Stegastes nigricans and bic...

The rate of emergence of micropredatory gnathiid isopods from the benthos, the proportion of emerging gnathiids potentially eaten by Labroides dimidiatus , and the volume of blood that gnathiids potentially remove from fishes (using gnathiid gut volume) were determined. The abundance (mean ± s.e .) of emerging gnathiids was 41·7 ± 6·9 m −2 day −1 and 4552 ± 2632 reef −1 day −1 (reefs 91–125 m 2 ). The abundance of emerging gna...

A gnathiid species (Crustacea: Isopoda; one of the most common ectoparasites of coral reef fishes) from the Great Barrier Reef, Australia, was allowed to choose among fishes from three different families to feed on (using two species of fishes per family). Gnathiids showed a strong preference for labrids, rarely feeding on pomacentrids or apogonids. In a separate experiment, gnathiid host preference did not vary among three la...

To determine whether the choice of client fishes in the cleaner fish Labroides dimidiatus was influenced by client size, cleaner fish were given a choice of equal amount of food spread on large and small client redfin butterflyfish Chaetodon trifasciatus models. All large models received bites from cleaners compared to 27% for small models. Seventy‐nine per cent of cleaners took their first bite from the large fish model. The...

Captive Hemigymnus melapterus exposed to large numbers of cultured juvenile parasitic isopods ( Gnathia sp.) had significantly lower haematocrit (median 27·62% ± 5·83% inter‐quartile range) than uninfected, control fish (median 32·73% ± 4·90%). This study is the first to show that juvenile Gnathia sp. reduce total blood volume in H. melapterus . The low haematocrit in infected fish was most likely due to plasma replacing eryth...