Fluctuating sexual dimorphism and differential hibernation by sex in a primate, the gray mouse lemur ( Microcebus murinus )

Schmid, Jan; Kappeler, Peter M.

doi:10.1007/s002650050474

Cited by 140 publications

(206 citation statements)

References 45 publications

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“…However, our study species exhibits an unusual life history, where weak dimorphism in body mass naturally fluctuates throughout the annual cycle owing to a seasonal sex bias in activity [39]. In captivity, average female body mass fluctuates between 80 g in summer and 120 g in winter, which is of the same magnitude as the body mass variations observed in the present experiment [54].…”

Section: Discussionsupporting

confidence: 52%

“…The brevity of female sexual receptivity allows obtaining a complete record of their mating activity [38]. Moreover, their small size, combined with a slight and seasonally fluctuating sexual dimorphism in body mass resulting from a sex differential use of energy savings during the winter period [39] offers the rare opportunity to conduct mating experiments and to manipulate sexual size dimorphism in a primate species.…”

Section: Introductionmentioning

confidence: 99%

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Convenience polyandry or convenience polygyny? Costly sex under female control in a promiscuous primate

et al. 2011

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Classic sex roles depict females as choosy, but polyandry is widespread. Empirical attempts to understand the evolution of polyandry have often focused on its adaptive value to females, whereas 'convenience polyandry' might simply decrease the costs of sexual harassment. We tested whether constraint-free female strategies favour promiscuity over mating selectivity through an original experimental design. We investigated variation in mating behaviour in response to a reversible alteration of sexual dimorphism in body mass in the grey mouse lemur, a small primate where female brief sexual receptivity allows quantifying polyandry. We manipulated body condition in captive females, predicting that convenience polyandry would increase when females are weaker than males, thus less likely to resist their solicitations. Our results rather support the alternative hypothesis of 'adaptive polyandry': females in better condition are more polyandrous. Furthermore, we reveal that multiple mating incurs significant energetic costs, which are strikingly symmetrical between the sexes. Our study shows that mouse lemur females exert tight control over mating and actively seek multiple mates. The benefits of remating are nevertheless not offset by its costs in low-condition females, suggesting that polyandry is a flexible strategy yielding moderate fitness benefits in this small mammal.

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Section: Discussionsupporting

confidence: 52%

Section: Introductionmentioning

confidence: 99%

Convenience polyandry or convenience polygyny? Costly sex under female control in a promiscuous primate

et al. 2011

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“…For W10, a sex-specific smoother term for 'day of year' was created to allow for sex-specific seasonal fluctuations [35]. For W10 and C10, a smoother term for age was used to describe age trajectories of BM.…”

Section: (B) Lifetime Body Mass Trajectoriesmentioning

confidence: 99%

“…To estimate flexible age trajectories of BM and control for the expected nonlinear seasonal BM fluctuation [35], we used additive mixed modelling (GAMM, mgcv-package [57]). For W10, a sex-specific smoother term for 'day of year' was created to allow for sex-specific seasonal fluctuations [35].…”

Section: (B) Lifetime Body Mass Trajectoriesmentioning

confidence: 99%

“…In mammals, including M. murinus [31], body growth typically ceases around the age of sexual maturity [32] (six to eight months in M. murinus [31,33]). Thereafter, BM fluctuates in response to imbalances in energy acquisition and expenditure, cyclic seasonal changes [21,34,35] or senescent muscle loss [36]. BM broadly reflects resources available for allocation to physiological processes, making it a meaningful indicator of FS.…”

Section: Introductionmentioning

confidence: 99%

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Senescence or selective disappearance? Age trajectories of body mass in wild and captive populations of a small-bodied primate

et al. 2014

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Classic theories of ageing consider extrinsic mortality (EM) a major factor in shaping longevity and ageing, yet most studies of functional ageing focus on species with low EM. This bias may cause overestimation of the influence of senescent declines in performance over condition-dependent mortality on demographic processes across taxa. To simultaneously investigate the roles of functional senescence (FS) and intrinsic, extrinsic and condition-dependent mortality in a species with a high predation risk in nature, we compared age trajectories of body mass (BM) in wild and captive grey mouse lemurs (Microcebus murinus) using longitudinal data (853 individuals followed through adulthood). We found evidence of non-random mortality in both settings. In captivity, the oldest animals showed senescence in their ability to regain lost BM, whereas no evidence of FS was found in the wild. Overall, captive animals lived longer, but a reversed sex bias in lifespan was observed between wild and captive populations. We suggest that even moderately condition-dependent EM may lead to negligible FS in the wild. While high EM may act to reduce the average lifespan, this evolutionary process may be counteracted by the increased fitness of the long-lived, high-quality individuals.

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Lemur traits and Madagascar ecology: Coping with an island environment

Wright¹

1999

Am. J. Phys. Anthropol.

510

496

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The last decade's lemur research includes successes in discovering new living and extinct species and learning about the distribution, biogeography, physiology, behavior, and ecology of previously little-studied species. In addition, in both the dry forest and rain forest, long-term studies of lemur demography, life history, and reproduction, have been completed in conjunction with data on tree productivity, phenology, and climate. Lemurs contrast with anthropoids in several behavioral features, including female dominance, targeted female-female aggression, lack of sexual dimorphism regardless of mating system, sperm competition coupled with male-male aggression, high infant mortality, cathemerality, and strict seasonal breeding. Hypotheses to explain these traits include the "energy conservation hypothesis" (ECH) suggesting that harsh and unpredictable climate factors on the island of Madagascar have affected the evolution of female dominance, and the "evolutionary disequilibrium hypotheses" (EVDH) suggesting that the recent megafauna extinctions have influenced lemurs to become diurnal. These hypotheses are compared and contrasted in light of recent empirical data on climate, subfossils, and lemur behavior. New data on life histories of the rain forest lemurs at Ranomafana National Park give further support to the ECH. Birth seasons are synchronized within each species, but there is a 6-month distribution of births among species. Gestation and lactation lengths vary among sympatric lemurs, but all lemur species in the rain forest wean in synchrony at the season most likely to have abundant resources. Across-species weaning synchrony seen in Ranomafana corroborates data from the dry forest that late lactation and weaning is the life history event that is the primary focus of the annual schedule. Lemur adaptations may assure maximum offspring survival in this environment with an unpredictable food supply and heavy predation. In conclusion, a more comprehensive energy frugality hypothesis (EFH) is proposed, which postulates that the majority of lemur traits are either adaptations to conserve energy (e.g., low basal metabolic rate (BMR), torpor, sperm competition, small group size, seasonal breeding) or to maximize use of scarce resources (e.g., cathemerality, territoriality, female dominance, fibrous diet, weaning synchrony). Among primates, the isolated adaptive radiation of lemurs on Madagascar may have been uniquely characterized by selection toward efficiency to cope with the harsh and unpredictable island environment.

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Fluctuating sexual dimorphism and differential hibernation by sex in a primate, the gray mouse lemur ( Microcebus murinus )

Cited by 140 publications

References 45 publications

Convenience polyandry or convenience polygyny? Costly sex under female control in a promiscuous primate

Convenience polyandry or convenience polygyny? Costly sex under female control in a promiscuous primate

Senescence or selective disappearance? Age trajectories of body mass in wild and captive populations of a small-bodied primate

Lemur traits and Madagascar ecology: Coping with an island environment

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