I’ve just stumbled across a really neat piece of research on host-parasite ecology. An article, provisionally available in BMC Ecology by Zohdy et al., describes movements of a species of louse that parasitises mouse lemurs. Occurring in Madagascar, mouse lemurs Microcebus rufus, are host to a species of louse, Lemurpediculus verruculosus (which is so highly host-specific it only occurs on M. rufus). The team of researchers did a mark-recapture study where they tracked the movements of lice between different hosts by marking them with nail polish and monitoring the dispersal of lice between different host lemurs.
They found that, generally, lemurs kept their lice to themselves, but occasionally, some would donate or collect lice. The actual mechanism by which the donation or collection occurs is not known – it’s not like trading lice is a common mouse lemur pastime, but it is probably linked to close contact via nest-sharing and other aspects of social ecology. Social interactions also increase during the breeding season, when the males are out on the prowl for the laydeez. There seemed to be no (identifiable) overarching factor driving the movement of lice within the population.
What surprised the authors was that there was a substantially higher degree of social interaction between lemurs across relatively large distances (600m is probably a long way when you’re a 40g primate). This also indicates that they may have an interesting social structure, of which we’re currently unaware.