Contrasting seasonal dynamics in fleas of the Siberian flying squirrel (Pteromys volans) in Finland

Abstract

Abstract 1. The seasonal and spatial variation of the adult flea fauna (Siphonaptera) was examined in connection with live‐trapping studies of the Siberian flying squirrel (Pteromys volans) in three study areas in southern Finland between 1997 and 2005.2. The numerically dominant flea species of the Siberian flying squirrel were Tarsopsylla octodecimdentata octodecimdentata and Ceratophyllus (Monopsyllus) indages indages (Ceratophyllidae); the latter being a host specialist of the Siberian flying squirrel. Tarsopsylla octodecimdentata, which also commonly occurs on the red squirrel (Sciurus vulgaris), infected a large proportion of the host population throughout the winter, whereas C. indages occurred predominantly during the summer and autumn, being practically the only flea species in nests during the flying squirrels’ breeding season and on juveniles still inhabiting their natal nest.3. The use of nest boxes by flying squirrels did not have any positive effects on flea populations, but it may have had a negative impact on T. octodecimdentata.4. The potentially vulnerable C. i. indages is a predictable, widespread component in the flea fauna of the Siberian flying squirrel at various spatial scales, and it is likely to occur in most of the permanent flying squirrel populations in Finland.