Culture-based methods were employed to recover 3929 isolates of fungi from soils collected in May and July 2014 from mound nests of Formica ulkei and adjacent non-nest sites. The abundance, diversity, and richness of species from nest mounds exceeded those of non-mound soils, particularly in July. Communities of fungi from mounds were more similar to those from mounds than non-mounds; this was also the case for non-mound soils with the exception of one non-mound site in July. Species of Aspergillus, Paecilomyces, and Penicillium were dominant in nest soils and represented up to 81.8% of the taxa recovered. Members of the genus Aspergillus accounted for the majority of Trichocomaceae from nests and were represented almost exclusively by Aspergillus navahoensis and Aspergillus pseudodeflectus. Dominant fungi from non-mound sites included Cladosporium cladosporioides, Geomyces pannorum, and species of Acremonium, Fusarium, Penicillium, and Phoma. Although mound nests were warmer than adjacent soils, the dominance of xerotolerant Aspergillus in soils from mounds and the isolation of the majority of Trichocomaceae at 25 and 35 °C suggests that both temperature and water availability may be determinants of fungal community structure in nests of F. ulkei.

Prey should adjust their defences against natural enemies to match their current level of risk and balance other needs. This is particularly important when optimal defences represent trade-offs, as is the case with many predator-induced trait-mediated indirect effects (TMIEs) that are antagonistic to those promoting host resistance to parasites and pathogens. However, trade-offs may depend on whether different natural enemies are present simultaneously or represent temporally discrete threats. We found that larval amphibians () previously exposed to predator cues did not engage in anti-parasite behaviours (activity increases) in response to a current risk of infection by a pathogenic trematode parasite compared to controls, resulting in higher infection intensities. This suggests that the memory of the likely more lethal threat (predation) had greater influence, maladaptively dampening tadpole activity. Incorporating complexity inherent in natural systems, including spatial and temporal overlap, is necessary to better understand natural enemy ecology and how TMIEs relate to infectious diseases.

Habitat attributes are known to influence infectious diseases such as those caused by parasites, but most studies have only considered single host and (or) parasite taxa, making it difficult to assess which features may be of general importance and to predict how alterations could affect disease dynamics. We examined infection with trematode (flatworm) parasites in two commonly co-occurring host taxa (larval amphibians and larval odonates (dragonflies and damselflies)) to investigate links with landscape-level features, including agricultural activity. We also assessed pond community composition with respect to the abundance and richness of aquatic arthropods known to prey upon tadpoles and (or) free-swimming trematode infectious stages. Larval amphibians from agricultural sites were most likely to be parasitized but had lower infection intensities, and infected hosts were positively associated with increasing distance to the nearest forest habitat, but negatively with road distance. The opposite was observed for larval odonate infection status; however, probability and intensity of parasitism in both host taxa was negatively associated with greater predatory arthropod abundance, consistent with the “dilution effect” of biodiversity on infectious diseases. Our approach demonstrates the importance of considering multiple host taxa when studying habitat links to diseases, and future studies incorporating even greater diversity will be needed.

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