Helminth parasites of the wood mouse Apodemus sylvaticus in Southern England: levels of infection, species richness and interactions between species.

Helminth parasites of the wood mouse, ( = 440), were surveyed in five localities, comprising woodland and grassland sites, in Southern England. Seven species of helminths were identified, among which and were dominant (prevalence = 79.1% and 54.1%, respectively). Less common species were the trematode (14.8%), cestodes (8.4%), (4.1%) and (3.4%) and the nematode (0.2%). Differences in prevalences between localities were found for , and and in abundances of , and . Age-dependent increases in both parameters were identified among species and for helminth species richness. The only species to show significant host sex bias was with prevalence values being higher in male mice. A number of different methods for exploiting raw data, and data corrected for significant confounding factors, were used to determine whether there were significant associations (prevalence) between species or quantitative interactions (abundance). The strongest evidence for a positive association was shown in concurrent infections with the trematode and the cestode (significant in the whole dataset and evident in each locality, both sexes and both age classes). The abundance of was also higher in mice with and vice versa. Overall, however, there was little support for associations or quantitative interactions between species, especially after data had been corrected for significant extrinsic/intrinsic factors, and we conclude that the helminths of wood mice in these communities are largely non-interactive and hence, perhaps better referred to as assemblages.