Phylogeny and systematics of mammal-associated psoroptidian mites (Acariformes:Astigmata:Psoroptidia) derived from external morphology

We used morphological characters to explore the phylogeny of mammal-associated psoroptidian mites. In both maximum parsimony and Bayesian analyses, the clades uniting Psoroptoidea and Analgoidea–Sarcoptoidea (higher Psoroptidia) were strongly supported, and monophyly of most sarcoptoid families was confirmed. However, the relationships among families of the higher Psoroptidia (Analgoidea and Sarcoptoidea) remained poorly resolved. Two most parsimonious trees were obtained after successive weighting. In these trees, higher Psoroptidia split into two main clusters with Sarcoptoidea in the traditional sense shown as diphyletic. Cluster I consists of two superfamilies: Analgoidea, including Dermationidae, and Psoroptoidea, stat. res.: Psoroptoidinae (Turbinoptidae–Paracoroptinae); (Pandalurinae (Pyroglyphidae–Lobalgidae); Paralgopsidae, stat. nov.–Ptyssalgidae (Epidermoptidae–Psoroptidae). Cluster II consists of the superfamily Sarcoptoidea represented by two lineages: Listropsoralgidae, stat. nov. (Myocoptidae (Rhyncoptidae–Sarcoptidae)) and Dromiciocoptidae, stat. nov. ((Listrophoridae–Atopomelidae) (Chirodiscidae (Gastronyssidae (Pneumocoptidae–Lemurnyssidae)))). We hypothesised that mites of the superfamilies Pterolichoidea, Analgoidea and Psoroptoidea have independently colonised birds with subsequent ancestral shifts of the families Lobalgidae and Psoroptidae and subfamily Paracoroptinae from birds to mammals. Mites of the superfamily Sarcoptoidea switched from nidicoly to parasitism on ancestors of therian mammals and evolved exclusively on this host group.

Searching for general patterns in parasite ecology: host identity versus environmental influence on gamasid mite assemblages in small mammals

The abundance and diversity of parasites vary among different populations of host species. In some host-parasite associations, much of the variation seems to depend on the identity of the host species, whereas in other cases it is better explained by local environmental conditions. The few parasite taxa investigated to date make it difficult to discern any general pattern governing large-scale variation in abundance or diversity. Here, we test whether the abundance and diversity of gamasid mites parasitic on small mammals across different regions of the Palaearctic are determined mainly by host identity or by parameters of the abiotic environment. Using data from 42 host species from 26 distinct regions, we found that mite abundances on different populations of the same host species were more similar to each other than expected by chance, and varied significantly among host species, with half of the variance among samples explained by differences between host species. A similar but less pronounced pattern was observed for mite diversity, measured both as species richness and as the taxonomic distinctness of mite species within an assemblage. Strong environmental effects were also observed, with local temperature and precipitation correlating with mite abundance and species richness, respectively, across populations of the same host species, for many of the host species examined. These results are compared to those obtained for other groups of parasites, notably fleas, and discussed in light of attempts to find general rules governing the geographical variation in the abundance and diversity of parasite assemblages.