Does sexual selection shape sex differences in longevity and senescence patterns across vertebrates? A review and new insights from captive ruminants.
In most mammals, both sexes display different survival patterns, often involving faster senescence in males. Being under intense sexual competition to secure mating opportunities, males of polygynous species allocate resources to costly behaviors and conspicuous sexual traits, which might explain these observed differences in longevity and senescence patterns. However, comparative studies performed to date have led to conflicting results. We aimed to resolve this problem by first reviewing case studies of the relationship between the strength of sexual selection and age-specific survival metrics. Then, we performed a comprehensive comparative analysis to test whether such relationships exist among species of captive ruminants. We found that the strength of sexual selection negatively influenced the onset of actuarial senescence in males, with males senescing earlier in polygynous than in monogamous species, which led to reduced male longevity in polygynous species. Moreover, males of territorial species senesced earlier but slower, and have a shorter longevity than males of species displaying other mating tactics. We detected little influence of the strength of sexual selection on the rate of actuarial senescence. Our findings demonstrate that the onset of actuarial senescence, rather than its rate, is a side effect of physiological mechanisms linked to sexual selection, and potentially accounts for observed differences in longevity.
CNRS, UMR5558, Laboratoire de Biométrie et Biologie Evolutive, F-69622, Université Lyon 1, Villeurbanne, France. morgane.tidiere@univ-lyon1.fr.
Morgane
M
Tidière
CNRS, UMR5558, Laboratoire de Biométrie et Biologie Evolutive, F-69622, Université Lyon 1, Villeurbanne, France.
Jean-Michel
JM
Gaillard
Zoological Garden Halle (Saale), Fasanenstr. 5a, 06114, Halle (Saale), Germany.
Dennis W H
DW
Müller
World Association of Zoos and Aquariums (WAZA), Gland, Switzerland.
Laurie Bingaman
LB
Lackey
UMR 5175, Modelling and Conservation, Centre d'Ecologie Fonctionnelle et Evolutive, Campus CNRS, 1919 route de Mende, 34293, Montpellier Cedex 5, France.
Olivier
O
Gimenez
Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, Winterthurerstr. 260, 8057, Zurich, Switzerland.
Marcus
M
Clauss
CNRS, UMR5558, Laboratoire de Biométrie et Biologie Evolutive, F-69622, Université Lyon 1, Villeurbanne, France.
Jean-François
JF
Lemaître
D000375:Aging; D000818:Animals; D000836:Animals, Zoo / Q000502:physiology; D008136:Longevity; D008322:Mammals / Q000502:physiology*; D052586:Mating Preference, Animal; D012418:Ruminants / Q000502:physiology; D012727:Sex Characteristics
Ageing; intrinsic physiological costs; mating system; ungulates