DOI 10.1007/s00442-009-1278-0COMMUNITY ECOLOGY- ORIGINAL PAPER Inferring associations among parasitic gamasid mites from census data
Abstract Within a community, the abundance of any given species depends in large part on a network of direct and indirect, positive and negative interactions with other species, including shared enemies. In communities where experimental manipulations are often impossible (e.g., par-asite communitie...
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| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.549.9308 http://www.otago.ac.nz/parasitegroup/PDF papers/Krasnovetal2009-Oecol.pdf |
| Summary: | Abstract Within a community, the abundance of any given species depends in large part on a network of direct and indirect, positive and negative interactions with other species, including shared enemies. In communities where experimental manipulations are often impossible (e.g., par-asite communities), census data can be used to evaluate the strength or frequency of positive and negative associations among species. In ectoparasite communities, competitive associations can arise because of limited space or food, but facilitative associations can also exist if one species sup-presses host immune defenses. In addition, positive associ-ations among parasites could arise merely due to shared preferences for the same host, without any interaction going on. We used census data from 28 regional surveys of gama-sid mites parasitic on small mammals throughout the Palae-arctic, to assess how the abundance of individual mite species is inXuenced by the abundance and diversity of other mite species on the same host. After controlling for several confounding variables, the abundance of individual mite species was generally positively correlated with the combined abundances of all other mite species in the com-munity. This trend was conWrmed by meta-analysis of the results obtained for separate mite species. In contrast, there were generally no consistent relationships between the abundance of individual mite species and either the species richness or taxonomic diversity of the community in which they occur. These patterns were independent of mite feeding mode. Our results indicate either that synergistic facilitative interactions among mites increase the host’s susceptibility to further attacks (e.g., via immunosuppres-sion) and lead to diVerent species all having increased abundance on the same host, or that certain characteristics make some host species preferred habitats for many parasite species. |
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