Sexual selection in the ring-tailed lemur (Lemur catta): Female choice, male mating strategies, and male mating success in a female dominant primate

Where male-male mating competition is intense, males are frequently larger than females, or have weaponry (e.g. enlarged canines) that females lack. Male dominance over females is often thought to be a by-product of selection for superior size and aggression. Paradoxically, some Malagasy primates show aggressive male-male competition over access to mates, yet lack sexual dimorphism in body size and dentition, and exhibit female dominance over males. This study’s purpose was to investigate female choice and male mating strategies in one such species, the ring-tailed lemur (Lemur catta), to compare the success of physically combative male mating strategies versus alternative non-combative strategies (i.e. sneak copulations). Data were collected across five breeding seasons (2000-2004) on St. Catherines Island, USA, on a provisioned free-ranging L. catta population. Four distinct L. catta groups were studied, two per breeding season, each group having 4-8 females and 2-4 non-natal males. The most commonly used male mating tactics were those that depended on physical contest competition among males. Alpha males often used their dominance status to gain first access to an estrus female, while non-alpha males frequently employed the use of dominance rank reversals as a mating strategy, which required aggressive challenges of more dominant males. Sneak and evasive copulations were also used, though much less often. Male sexual coercion of a female was also documented for the first time in this species. Male inter-troop transfer may be considered a successful mating strategy as well, for females in this study showed greater sexual preference for novel males, and males had higher mating success following a transfer. Female multiple mating was found to be extremely common. Although females mated with multiple males, alpha males were more likely to ejaculate earlier with a female than subordinate males, which may result in alpha males having higher reproductive success. In conclusion, physically combative competition appears to be critical to male mating success in L. catta. These findings provide further support for the hypothesis that sexual monomorphism in this species may have evolved because sperm competition or male stamina is more important than large body size in determining male reproductive success.