Dominance rank reversals and rank instability among male Lemur catta: the effects of female behavior and ejaculation.

In this study, dominance rank instability among male Lemur catta during mating was investigated. Also, data on agonism and sexual behavior across five consecutive mating seasons in a population of L. catta on St. Catherines Island, USA, were collected. Instances of male rank instability were categorized into three types. Type 1 consisted of a temporary switch in the dominance ranks of two males, which lasted for a period of minutes or hours. Type 2 dyadic male agonistic interactions showed highly variable outcomes for a period of time during which wins and losses were neither predictable nor consistent. Type 3 interactions consisted of a single agonistic win by a lower-ranked male over a more dominant male. More Type 2 interactions (indicating greater dominance instability) occurred when males had not spent the previous mating season in the same group, but this trend was not statistically significant. The majority of periods of male rank instability were preceded by female proceptivity or receptivity directed to a lower-ranked male. As such, exhibition of female mate choice for a lower-ranking male appeared to incite male-male competition. Following receipt of female proceptivity or receptivity, males who were lower-ranking took significantly longer to achieve their first agonistic win over a more dominant male than did males who were higher-ranked. Ejaculation frequently preceded loss of dominance. In conclusion, temporary rank reversals and overall dominance rank instability commonly occur among male L. catta in mating contexts, and these temporary increases in dominance status appear to positively affect male mating success.

Parga JA 《-》

Effects of reproductive and social variables on fecal glucocorticoid levels in a sample of adult male ring-tailed lemurs (Lemur catta) at the Beza Mahafaly Reserve, Madagascar.

Gould L ，Ziegler TE ，Wittwer DJ 《AMERICAN JOURNAL OF PRIMATOLOGY》

Variation in fecal testosterone levels, inter-male aggression, dominance rank and age during mating and post-mating periods in wild adult male ring-tailed lemurs (Lemur catta).

In primate species exhibiting seasonal reproduction, patterns of testosterone excretion in adult males are variable: in some species, peaks correlate with female receptivity periods and heightened male-male aggression over access to estrous females, in others, neither heightened aggression nor marked elevations in testosterone have been noted. In this study, we examined mean fecal testosterone ( f T) levels and intermale aggression in wild adult male ring-tailed lemurs residing in three groups at Beza Mahafaly Reserve, Madagascar. Results obtained from mating and post-mating season 2003 were compared to test Wingfield et al. [1990. Am Nat 136:829-846] "challenge hypothesis", which predicts a strong positive relationship between male testosterone levels and male-male competition for access to receptive females during breeding season. f T levels and rates of intermale aggression were significantly higher during mating season compared to the post-mating period. Mean f T levels and aggression rates were also higher in the first half of the mating season compared with the second half. Number of males in a group affected rates of intermale agonism, but not mean f T levels. The highest-ranking males in two of the groups exhibited higher mean f T levels than did lower-ranking males, and young males exhibited lower f T levels compared to prime-aged and old males. In the post-mating period, mean male f T levels did not differ between groups, nor were there rank or age effects. Thus, although male testosterone levels rose in relation to mating and heightened male-male aggression, f T levels fell to baseline breeding levels shortly after the early mating period, and to baseline non-breeding levels immediately after mating season had ended, offsetting the high cost of maintaining both high testosterone and high levels of male-male aggression in the early breeding period.

Gould L ，Ziegler TE 《AMERICAN JOURNAL OF PRIMATOLOGY》

Male aggression during mating: evidence for sexual coercion in a female dominant primate?

Parga JA ，Henry AR 《-》

Evaluation of male inter-troop transfer as a mating strategy among ring-tailed lemurs on St. Catherines Island, USA.

One commonly cited function of dispersal is to increase mating opportunities. In this study, I evaluated the hypothesis that male inter-troop transfer is used as a mating strategy in ring-tailed lemurs, Lemur catta, on St. Catherines Island (SCI), Ga., USA. I measured male mating success and inter-troop transfer behavior across 5 years in a population consisting of 4 lemur groups on SCI. Data strongly supported dispersal as a successful mating strategy of natal males, because these males did not mate within their natal groups, but always mated in their new groups of entry. For secondary male dispersal (transfers between 2 non-natal groups), data on 2 males collected in breeding seasons immediately prior to and following transfer show that their individual mating success measures increased following a transfer. Data revealed that among non-natal males, high-ranking males on SCI were more likely to transfer between groups than lower-ranking males, which is somewhat contrary to the more common trend among primates of lower-ranking males transferring more frequently. In sum, male primary dispersal appears to function as a mating strategy among male L. catta on SCI, with indications that secondary dispersal may also be successful at increasing male mating success.

Parga JA 《-》