Spatial distribution and population composition of the brown mouse lemur (Microcebus rufus) in Ranomafana National Park, Madagascar, and its implications for social organization

Through a 16-mo mark-recapture trap study, I examined aspects of spatial di stribution and population composition in the brown mouse lemur, Microcebus rufus, a 42 g nocturnal strepsirhine. The study took place in the rainfores t of Ranomafana National Park in southeastern Madagascar. Sherman live trap s were set monthly for a variable number of nights in a quasi-grid 50 m apa rt. Captured individuals were marked for future identification and released at site of capture. More males than females were captured overall (102 ver sus 72) and at 83% of trap sites. Trap sex ratio fluctuated significantly o ver the course of the study. It was particularly male-biased between June a nd August (3.9:1), when more previously uncaptured males than females (14 v ersus 6) entered the trap population. Some of these males remained in the t rap population. Although the average number of individuals captured was not significantly different between the first four and last four months of the study, the composition of the population changed. The female population, h owever, changed less: 28.9% of all females captured in the first four month s of the study were recaptured in the last four months, compared to 9.7% of males. It is suggested that the pattern of appearance of new individuals a nd disappearance of others, both predominantly male, may indicate migratory activity. Furthermore, an average of eight individuals were captured at ea ch trap site (similar to 70% of traps captured more than five), suggesting a high degree of spatial overlap. The average number of male and female ind ividuals captured in each trap (5.5 males versus 2.5 females), the average number of trap sites at which males and females were captured (3.6 versus 2 .4), and the average number of captures for males and females (9.8 versus 5 .7) all differed significantly between the sexes. Am. J. Primatol. 51:61-78 , 2000. (C) 2000 Wiley-Liss, Inc.