Some Aspects of the Ecology and Biology of Some Small Mammal Fleas from Yorkshire

Abstract

Studies on the populations of small mammals and their fleas are very suitable for school biology projects at varying levels. The field work itself, its methods and the handling of the data obtained, can be directly dealt with only by the brighter senior pupils, but some relevant studies of the general biology and habitat preferences of the small mammal hosts can be usefully appreciated at Grammar School third-form level. The information can be used to demonstrate general biological and particular ecological principles from first-hand experience. A considerable amount of live trapping for all species of small mammals was undertaken in a variety of habitats around Keighley and in other areas of the country using Longworth Small Mammal Traps. The most intensive work was from November 1964 to June 1966 at Crookrise near Skipton, Yorkshire, on the field vole Microtus agrestis. Each trapping session, of which there were generally two per month, consisted of three visits to the area, the first to lay the traps, varying in number from about 120 to 160, the second and third to examine the captures, after which they were released, and finally the return of the traps to the school laboratory for cleaning and preparation for the next visit. The purpose was partly to determine the numbers of field mice, voles and shrews present in the area throughout the year, and their habits, but chiefly to gain information concerning their fleas. Mead-Briggs (1960, 1964), Rothschild (Rothschild & Ford, 1964, 1966) and other workers have recently shown that the rabbit flea Spilopsyllus cuniculi requires hormones produced by the host to trigger off and maintain its own breeding cycle. This survey showed, however, that this is probably not the case with most small-mammal fleas. It appears as though in Microtus agrestis, the bankvole Clethrionomys glareolus, and in particular the woodmouse Apodemus sylvaticus, in the summer months it is mature males which are more often infested and carry a larger population of fleas than do mature females and immatures of both sexes. No