APODEMUS-SYLVATICUS INFECTED WITH HELIGMOSOMOIDES-POLYGYRUS (NEMATODA) IN AN ARABLE ECOSYSTEM - EPIDEMIOLOGY AND EFFECTS OF INFECTION ON THE MOVEMENTS OF MALE-MICE

We studied the epidemiology of Heligmosomoides polygyrus (Nematoda) in the wood mouse (Apodemus sylvaticus) in an arable ecosystem, and inve stigated any association between infection and the movement patterns o f male mice by manipulating worm burdens. Methods included the live-tr apping of mice, estimation of worm burdens by faecal analysis, adminis tration of either an anthelminthic or water (as a control) and the rad io-tracking of selected animals. Heligmosomoides polygyrus showed an o verdispersed distribution pattern, with prevalence tending to be highe r in males and heavier mice. Prevalence and intensity peaked in spring and declined in autumn both in the entire population and in adults. T his seasonality in the arable ecosystem in comparison to woodland may arise due to the direct and indirect impact of agricultural practice. To investigate the link between infection and movements, radio-tracked mice were classed as either 'Uninfected' or 'Infected'; mice were als o classed as either 'Control' or 'Dosed'. There were no significant di fferences in movement parameters between 'Infected/Dosed' and 'Infecte d/ Control', possibly because treatment was not administered sufficien tly frequently. Both 'Infected' classes of mice moved significantly fa ster than 'Uninfected' ones, and 'Infected/ Dosed' mice moved signific antly further than 'Uninfected' ones. The percentage of time spent mov ing was also greater, and the home range area was larger, for 'Infecte d/Dosed' and 'Infected/ Control' than for 'Uninfected' mice. The obser ved differences in movement may have been the result of either the beh aviour of mice influencing their parasite load or the parasite manipul ating its host.