Ecological Analysis of the Helminth Community and Its Relationship with the Physiological State in the Montane Water Vole, Arvicola scherman (Shaw, 1801), in NW Spain

The montane water vole, Arvicola scherman, is a fossorial rodent that lives underground in grasslands, pastures and meadows in the mountain ranges of southwestern and central Europe. It feeds mainly on grasses, roots, and bulbs, causing considerable economic damage to agriculture. Consequently, it is recognised as one of the most important pest vole species in European agroecosystems. The dynamics of these pest populations may be affected by interactions with their parasites. For this reason, an helminthoecological study was carried out in Asturias (NW Spain), analysing a total of 815 montane water voles, 464 (56.9%) of which were parasitised by at least one of the six helminth species detected: Hydatigera taeniaeformis s.l. larvae (9%), Aonchotheca wioletti (0.1%), Eucoleus bacillatus (0.4%), Trichuris arvicolae (7%), Carolinensis minutus (30%) and Syphacia nigeriana (12%). The helminth community found was compared with that reported from A. scherman analysed in other locations of the Iberian Peninsula. This study also analyses the influence of intrinsic and extrinsic factors on the prevalence and abundance of the helminth component species, with host age and body condition being the most influential determinants. H. taeniaeformis s.l. and T. arvicolae are postulated as potential regulators of the analysed population, a pest in crops from NW Spain.