Which factors regulate the reproduction of ectoparasites of temperate-zone cave-dwelling bats?

Abstract

We studied the factors which regulate the reproduction of ectoparasites of temperate-zone cave-dwelling bats, using the Schreiber's bat (Miniopterus schreibersii) and its ectoparasites as a model. For this, we searched 969 bats during 2003 and 2004 at important stages of the bat yearly cycle and found four ectoparasite species regularly occurring on them: two nycteribiids (Nycteribia schmidlii and Penicillidia conspicua), one wing mite (Spinturnix psi), and one hard tick (Ixodes simplex simplex). These parasites were present throughout the yearly cycle, but their reproductive activity greatly fluctuated seasonally. Also, we found that sex, age, and reproductive status of the host strongly influenced the reproductive activity of parasites. Overall, the four parasite species had a similar reproductive pattern, reproducing more intensively during the pregnancy and nursing seasons of M. schreibersii, mainly on pregnant and juvenile bats. Moreover, parasites greatly reduced reproductive activity during winter, while bats were in deep torpor or hibernating. We conclude that reproduction in ectoparasites of M. schreibersii and of many other temperate cave-dwelling bats is mostly regulated by the reproductive cycle of their bat hosts, but also limited by roost temperatures during winter. The fact that the reproductive cycle of parasite species of such distinct taxonomic groups are similarly adjusted to that of their bat host suggests that this adjustment is a highly adaptive trait.