The costs of risky male behaviour: sex differences in seasonal survival in a small sexually monomorphic primate - PubMed (original) (raw)

The costs of risky male behaviour: sex differences in seasonal survival in a small sexually monomorphic primate

Cornelia Kraus et al. Proc Biol Sci. 2008.

Abstract

Male excess mortality is widespread among mammals and frequently interpreted as a cost of sexually selected traits that enhance male reproductive success. Sex differences in the propensity to engage in risky behaviours are often invoked to explain the sex gap in survival. Here, we aim to isolate and quantify the survival consequences of two potentially risky male behavioural strategies in a small sexually monomorphic primate, the grey mouse lemur Microcebus murinus: (i) most females hibernate during a large part of the austral winter, whereas most males remain active and (ii) during the brief annual mating season males roam widely in search of receptive females. Using a 10-year capture-mark-recapture dataset from a population of M. murinus in Kirindy Forest, western Madagascar, we statistically modelled sex-specific seasonal survival probabilities. Surprisingly, we did not find any evidence for direct survival benefits of hibernation-winter survival did not differ between males and females. By contrast, during the breeding season males survived less well than females (sex gap: 16%). Consistent with the 'risky male behaviour' hypothesis, the period for lowered male survival was restricted to the short mating season. Thus, sex differences in survival in a promiscuous mammal can be substantial even in the absence of sexual dimorphism.

PubMed Disclaimer

Figures

Figure 1

Figure 1

Semi-annual apparent survival probabilities of M. murinus during (a) winter (non-breeding season) and (b) summer (breeding season; filled circles, ad F; filled squares, ad M; open circles, yrl F; open squares, yrl M). Depicted are model-averaged MLEs and unconditional SEs (ad, adult; juv, juvenile; yrl, yearling; F, female; M, male).

Figure 2

Figure 2

Sex differentials in apparent survival probability of M. murinus over the breeding season: before, during and after the mating period in (a) 1999 and (b) 2000 (circles, females; squares, males). Depicted are model-averaged MLEs and unconditional SEs.

Similar articles

Cited by

References

    1. Alberts S.C, Altmann J. Balancing costs and opportunities: dispersal in male baboons. Am. Nat. 1995;145:279–306. doi:10.1086/285740 - DOI
    1. Austad S.N. Why women live longer than men: sex differences in longevity. Gend. Med. 2006;3:79–92. doi:10.1016/S1550-8579(06)80198-1 - DOI - PubMed
    1. Boonstra R, McColl C.J, Karels T.J. Reproduction at all costs: the adaptive stress response of male Arctic ground squirrels. Ecology. 2001;82:1930–1946.
    1. Brei B, Fish D. Comment on “Parasites as a viability cost of sexual selection in natural populations of mammals”. Science. 2003;300:55A. doi:10.1126/science.1079746 - DOI - PubMed
    1. Brunet-Rossinni A.K, Austad S.N. Ageing studies on bats: a review. Biogerontology. 2004;5:211–222. doi:10.1023/B:BGEN.0000038022.65024.d8 - DOI - PubMed

Publication types

MeSH terms

LinkOut - more resources