Linking species abundance distributions and body size in monogenean communities

Abstract

Parasite communities are characterised by one or a few numerically dominant species and many rare species. Although this pattern is well recognised, its underlying causes remain unknown. In this study, we tested whether variation in abundance among species within parasite communities can be explained by interspecific variation in body size. We used data on nine fish species (families Serranidae and Lethrinidae) from New Caledonia, each harbouring strictly host-specific diplectanid monogenean species with very uneven abundances. On each fish species, the most abundant monogenean species accounted for between one half and two thirds of all individuals recovered from the community, and its abundance was between 2 and 114 times greater than that of the second-most abundant species. However, there was no convincing evidence that the ratio of abundance values between the two most abundant species in a community co-varied with the ratio in their body sizes; thus, size differences cannot explain these differences in abundances between common species. It is surprising to note that in two of the three communities with enough species for an analysis to be performed, body size tended to correlate positively with abundance among all species of diplectanid monogeneans. Thus, although body size variation on its own cannot account for the pronounced differences in abundance among monogenean species within the same community, body size remains an important determinant of abundance as it relates to life-history traits underpinning reproductive rates and population growth in these unsaturated communities.

Determinants and consequences of interspecific body size variation in tetraphyllidean tapeworms

“…In nematodes parasitising mammals, the relationship between intensity of infection, a measure of parasite density within each infected host, and parasite body size is consistent with that observed in free-living taxa (Arneberg et al 1998). However, those reported for other groups of parasites sometimes reveal a positive relationship between body size and abundance (Poulin 1999;Poulin and Justine 2008). The results of this study suggest that among tetraphyllidean cestodes parasitising elasmobranch Wshes, parasite length is negatively correlated with intensity of infection (Fig.…”

Seasonal variation in metazoan parasites of Trichiurus lepturus (Perciformes: Trichiuridae) of Rio de Janeiro, Brazil

“…The schooling behaviour and body size of the host are important to the dynamics of populations of ectoparasites, as a greater density of fish forming schools and larger area for infestation facilitate the spread of the parasite in the population (Ranta, 1992;Sasal and Morand, 1998;Raibaut et al, 1998;Poulin and Justine, 2008;Takemoto et al, 2009). In T. lepturus, individuals above 50 cm in length form schools that migrate, with movement and distribution influenced by oceanographic conditions (FAO, 2005).…”

Four species of Pseudorhabdosynochus (Monogenea: Diplectanidae) from the camouflage grouper Epinephelus polyphekadion (Perciformes: Serranidae) off New Caledonia

“…Larger fish did not have more monogeneans than the smaller ones, and no seasonal influence could be detected. Finally, the total number of diplectanids on this fish species corresponds with the general pattern previously reported for several fish species (Poulin & Justine, 2008), with a dominant species (here P. crassus n. sp.…”