Parasite examination

To characterize patterns of parasite taxonomic richness and abundance, we measured each invertebrate host using digital calipers (total length, mm) and carefully examined for ectoparasites using a dissecting microscope at 40–100× magnification (SZX10, Olympus, Shinkuku, Tokyo, Japan). We counted all ectoparasites and placed a subsample on a slide for identification under 200–400× magnification. The host was subsequently dissected by cutting along the lateral sides, removing the internal organs, and examining the compressed tissues between two slides (25 × 75 × 1 mm) under a compound microscope (SZX10, Olympus, Shinkuku, Tokyo, Japan). We used multiple taxonomic keys to identify parasites to lowest taxonomic level; although species-level identifications were generally not possible given that many of the infections constitute larval stages, we identified trematode (Platyhelminth) and gregarine (Apicomplexan) parasites to genus, juvenile acanthocephalans and nematodes to phylum, and mites (Arthropoda) to subclass (Poinar 1975, Schnell 1985, Clopton 2002, Thorp and Covich 2009).