Phylogenetic and compositional diversity are governed by different rules: a study of fleas parasitic on small mammals in four biogeographic realms

Abstract

We studied patterns of phylogenetic and compositional diversity of fleas parasitic on small mammals and asked whether these patterns are affected by environmental variation or evolutionary/historical processes. We considered environmental variation via both off‐host (air temperature, precipitation, the amount of green vegetation, latitude) and host‐associated (phylogenetic and species composition) environments. The indicators of evolutionary/historical processes were phylogenetic and compositional uniqueness estimated via phylogenetic or compositional, respectively, β‐diversity of either fleas or hosts. We found that phylogenetic uniqueness of flea assemblages was the main predictor of their phylogenetic diversity in all realms. In addition, host phylogenetic diversity and uniqueness played also some role in the Palearctic, whereas the effect of the off‐host environment was either extremely weak or absent. Compositional diversity of fleas was consistently affected by compositional diversity of hosts in all realms except the Neotropics. The effect of the off‐host environment on compositional flea diversity was substantial in all realms except the Palearctic. No effect of latitude on either metric of flea diversity was found. We conclude that phylogenetic diversity of fleas is driven mainly by evolutionary/historical processes, whereas drivers of their compositional diversity are associated with current ecological conditions.

Avian host composition, local speciation and dispersal drive the regional assembly of avian malaria parasites in South American birds

“…The LDG has been observed in some micro‐ and macroparasite–host systems, such as ectoparasites of marine fishes (Rohde & Heap, ), vector‐transmitted protozoan parasites of primates (Nunn et al, ), directly transmitted viruses of rodents (Bordes, Guégan, & Morand, ) and helminths in several vertebrate host taxa (Dallas et al, ). However, many other studies have failed to show an effect of latitude on parasite diversity (Poulin, ; Bordes, Morand, Krasnov, & Poulin, ; see Kamiya et al, for a meta‐analysis; Clark, ; Krasnov et al, ). These contradictory results in latitudinal patterns of diversity among host–parasite systems could be explained by differences in parasite life cycle and modes of transmission (Bordes et al, ).…”

Contrasting responses of beta diversity components to environmental and host‐associated factors in insect ectoparasites

“…For example, a study of flea alpha diversity in four biogeographical realms demonstrated that phylogenetic alpha diversity was associated with the internal structure of their assemblages (e.g. phylogenetic uniqueness), whereas compositional alpha diversity was affected mainly by host diversity and environment (Krasnov et al ., ). This might occur if the species composition of a local community mainly reflects current ecological conditions, whereas the phylogenetic composition of this community mainly represents a legacy of past historical/evolutionary processes.…”

“…The results of the present study, however, suggest that the pattern of the relative effects of different factors (both environmental and host‐associated in the case of parasites) on beta diversity is context‐dependent and may differ among different facets of beta diversity. The reason behind this may be that compositional and phylogenetic beta diversity can be governed by different rules, similarly to the case of alpha diversity (Krasnov et al ., , ). For example, a study of flea alpha diversity in four biogeographical realms demonstrated that phylogenetic alpha diversity was associated with the internal structure of their assemblages (e.g.…”

“…As a backbone of rodent phylogeny, we used the global phylogenetic supertree for mammals of Bininda‐Emonds et al . () and then modified the topology of branches corresponding to rodent families, genera and species using phylogenetic trees from various recent sources (Krasnov et al ., ). In both trees, the length of all branches was set to an equal length of 1, and the trees were arbitrarily ultrametricised using mesquite , version 3.51 (Maddison & Maddison, ).…”

Host phylogeny and ecology, but not host physiology, are the main drivers of (dis)similarity between the host spectra of fleas: application of a novel ordination approach to regional assemblages from four continents

“…Many comparative studies that have aimed to elucidate the factors determining the compositional and phylogenetic structure of host spectra were carried out using fleas (Siphonaptera) parasitic on small mammals as a model taxon (Krasnov et al, 2005a(Krasnov et al, , 2014(Krasnov et al, , 2019. These studies repeatedly demonstrated that the species and phylogenetic compositions of host spectra in these parasites were strongly affected by the species composition and/or phylogenetic structure of the available host pool.…”