The fleas of a population of weasels in Wytham Woods, Oxford

Weasels were regularly livetrapped, anaesthetized and searched for fleas over two years, in Wytham Woods, near Oxford. Eleven species of fleas were identified among 262 collected. Seven normally occur on small rodents, one on rats, two on moles and one on birds. Fleas were collected on 103 of 338 occasions when an unconscious weasel was examined; on average males carried 0·6 fleas, females 1·5 fleas, but there was no significant difference between the proportion of males and females infested. The species distribution of the fleas on weasels in Wytham suggests that they acquire their fleas mainly from the nests and runways of their prey, which they have hunted through or taken over. Important prey, e.g. birds (22% of prey items identified) with uninviting nests contributed few fleas (2%); non-prey, e.g. moles (0–4% of items) with highly desirable nests, contributed disproportionately many, including 35 fleas (15%) of two species otherwise monoxenous on moles. A similar pattern is shown by the fleas carried by stoats in New Zealand.