Brown mouse lemurs are small, big-eyed nocturnal primates that dwell in the dense rainforests of Madagascar. Mouse lemurs are the only known host of the parasitic louse Lemurpediculus verruculosus. The lice are evolved to stay attached to the sparse hair of the lemurs' ears, but lice can also be found on the eyelids and testicles. The lice can only survive for a couple of hours without their host. Therefore, if a louse changes host, it happens mainly by direct contact.
A team of researchers from Finland, USA and Madagascar decided to tag individual lice from trapped lemurs to see what kind of social interactions the lemurs might have. – We used coloured nail varnish for tagging, tells Sarah Zohdy from the University of Helsinki about the methods.
After lice tagging, mouse lemurs were set free again. After that, each trapped lemur was checked for coloured lice. Results show that lice were transferred between 43% of the population. All of them were males who from previous studies are known to share nest-holes. – However, louse transfer peaked during the breeding season, indicating a greater number of social interactions. Probably the contacts were conflicts over females, Sarah Zohdy explains.
Louse transfer did not correlate with lemur age. The eldest male had a heavy louse infestation and collected lice from many donors. The youngest male had the worst louse infestation but donated only one louse. Some males appeared to be superspreaders donating but not collecting lice.
Louse transfer showed that the mouse lemurs travel greater distances and interact over a wider geographic area than previously was thought.
Mapping the Social Network: Tracking lice in a wild primate (Microcebus rufus) population to infer social contacts and vector potential. Sarah Zohdy, Addison D Kemp, Lance A Durden, Patricia C Wright and Jukka Jernvall. BMC Ecology
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