Predictors of agonism and affiliation in black-and-white ruffed lemurs (Varecia variegata) [article]

Li-Dunn Chen, University Of Calgary, Steig E. Johnson
Agonism and affiliation work complementarily to influence social ranking in primate social systems, which ultimately impacts reproductive success. In this two-part study, I investigated social behaviour of the Critically Endangered black-and-white ruffed lemur, a highly frugivorous species characterized by female dominance, fission-fusion dynamics, synchronized breeding, and communal care of offspring. Although ruffed lemur sociality has been described in the literature, specific seasonal and
more » ... ological predictors of agonism and affiliation have not been quantitatively investigated. Behavioural data were collected in the Kianjavato commune of southeastern Madagascar. I first investigated fluctuating food availability and reproductive season as predictors of agonism. Food availability had no effect on group-wide agonism rates, but subgroup size and breeding seasons were highly predictive of increased agonism. Increased agonism rates were observed when subgroups were larger as well as during the mating and birthing seasons, but only in years when mating and birthing occurred. I speculate these patterns of agonism function as reproductive strategies, as male-male competition for access to mates is expected to increase during the mating season, and parents likely exhibit more agonism while guarding their offspring during the birthing season. In order to better understand the behavioural strategies employed by ruffed lemurs during the mating season, I also investigated how male individuals vary in their expression of agonistic and affiliative behaviours with respect to reproductive season and dominance rank. I found that males exhibited higher rates of both agonism and affiliation during the mating season compared to the post-mating season, and that dominant males expressed higher rates of agonism but not affiliation compared to low-ranking males. I also evaluated female agonism rates and ranks to determine if they were higher in females compared to males. Although females occupied the highest ranks within their subgr [...]
doi:10.11575/prism/38083 fatcat:clt3ahzyzjf3pot74hzabdxytq