Older conservatives: reproduction in female Alpine chamois (<i>Rupicapra rupicapra</i>) is increasingly risk-averse with age

Morin, Audrée; Rughetti, Marco; Rioux‐Paquette, Sébastien; Festa‐Bianchet, Marco

doi:10.1139/cjz-2015-0153

Cited by 22 publications

(28 citation statements)

References 85 publications

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“…The onset of reproductive senescence in both species occurs at about 13 years, 4–5 years after the start of actuarial senescence (Festa‐Bianchet & Côté, ; Festa‐Bianchet & King, ; Jorgenson et al, ). Older females appear to reduce allocation to reproduction and, as reported in chamois ( Rupicapra rupicapra ) (Morin, Rughetti, Rioux‐Paquette, & Festa‐Bianchet, ) and ibex (Rughetti et al, ), there may be more variability in reproductive potential among senescent than prime‐aged females. Older females appear increasingly conservative in their reproductive allocation, with a greater frequency of reproductive pauses.…”

Section: Age Modulates Costs Of Reproduction: Primiparity and Senescencementioning

confidence: 77%

Long‐term studies of bighorn sheep and mountain goats reveal fitness costs of reproduction

Festa‐Bianchet

Côté

Hamel

et al. 2019

Journal of Animal Ecology

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Fitness costs of reproduction are expected when resources are limited. Costs drive the evolution of life‐history strategies and can affect population dynamics if females change their allocation of resources to reproduction. We studied fitness costs of reproduction in mountain ungulates in Alberta, Canada. We monitored two populations of bighorn sheep (Ovis canadensis) for 44 and 30 years, and one of mountain goats (Oreamnos americanus) for 30 years. Both species are highly iteroparous. Heterogeneity in individual reproductive potential makes fitness costs of reproduction difficult to detect and quantify without manipulations. In capital breeders, individual differences can be partly accounted for by considering body mass and other correlates of reproductive potential. Long‐term monitoring can reveal costs that only manifest under stressful conditions such as disease or resource scarcity. Despite individual differences in reproductive potential, we detected fitness costs of reproduction in females. Costs, in terms of mass gain and survival, are almost entirely born by subsequent offspring, as mothers prioritize their own maintenance and survival. Costs are greater for primiparous females, decrease with increasing body mass and increase as resource availability declines, and sons are costlier than daughters. Costs may increase for senescent females that appear to reduce allocation to reproduction. In bighorn sheep, costs mostly involve reduced mass gain and lower survival of subsequent offspring. In mountain goats, costs include reductions in mass gain, subsequent fecundity and juvenile survival. In males, fitness costs derive mostly from attempts to reproduce rather than from siring success and likely depend upon individual competitiveness. In the absence of selective harvests, dominant males may enjoy high fitness and possibly lower costs compared to subordinates. The conservative reproductive tactic of mountain ungulate females likely explains why density dependence mostly involves later primiparity and lower recruitment, but rarely affects adult survival. Future research will seek to better account for heterogeneity in reproductive potential, assess cumulative reproductive costs and investigate the potential effects of fathers on maternal allocation tactics.

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Section: Age Modulates Costs Of Reproduction: Primiparity and Senescencementioning

confidence: 77%

Long‐term studies of bighorn sheep and mountain goats reveal fitness costs of reproduction

Festa‐Bianchet

Côté

Hamel

et al. 2019

Journal of Animal Ecology

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“…Large‐horned females may thus allocate more resources to reproduction, but at the cost of survival at old ages. Although recent studies in female chamois show no clear evidence of reproductive costs in any age class (Morin, Rughetti, Rioux‐Paquette, & Festa‐Bianchet, ; Tettamanti, Grignolio, Filli, Apollonio, & Bize, ), such costs may only be evident in populations experiencing poor environmental conditions.…”

Section: Discussionmentioning

confidence: 92%

A negative association between horn length and survival in a weakly dimorphic ungulate

Douhard

Crampe

Loison

et al. 2020

Ecology and Evolution

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While all models of sexual selection assume that the development and expression of enlarged secondary sexual traits are costly, males with larger ornaments or weapons generally show greater survival or longevity. These studies have mostly been performed in species with high sexual size dimorphism, subject to intense sexual selection. Here, we examined the relationships between horn growth and several survival metrics in the weakly dimorphic Pyrenean chamois (Rupicapra pyrenaica). In this unhunted population living at high density, males and females were able to grow long horns without any apparent costs in terms of longevity. However, we found a negative relationship between horn growth and survival during prime age in males. This association reduces the potential evolutionary consequences of trophy hunting in male chamois. We also found that females with long horns tended to have lower survival at old ages. Our results illustrate the contrasting conclusions that may be drawn when different survival metrics are used in analyses. The ability to detect trade‐off between the expression of male secondary sexual traits and survival may depend more on environmental conditions experienced by the population than on the strength of sexual selection.

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“…The not statistically significant, albeit slightly negative, relationship between early horn growth and survival found in our study would thus suggest limited costs of early reproduction. Interestingly, recent studies did not find clear costs of reproduction at any age in female chamois, possibly owing to high individual heterogeneity in reproductive performance (Morin, Rughetti, Rioux‐Pasquette, & Festa‐Bianchet, ; Tettamanti, Grignolio, Filli, Apollonio, & Bize, ).…”

Section: Discussionmentioning

confidence: 94%

“…In chamois, the fact that females tend to live in larger groups than males (Krämer, 1969) likely increases the possibility for hunters to select individuals with longer horns (Mysterud, 2011). Given the positive correlation between early horn growth and age of primiparity (Rughetti & Festa-Bianchet, 2011a), and the occurrence of individual heterogeneity in reproductive performance (Morin et al, 2016), the possibility of trophy hunting on female chamois deserves to be taken into account when evaluating the demographic effects of different selective regimes, as it is likely to deeply affect population dynamics T A B L E 2 Generalized least square models fitted to explain sex-specific variations in horn length (L2) and body mass of yearling chamois (n = 688 males and n = 539 females) harvested in Sondrio between 1999 and 2013. The table reports values of partial regression slopes (Estimate), standard errors (Std.…”

Section: Body Mass (In Kg)mentioning

confidence: 99%

“…Horn length in the first 2 years of life, for example, positively correlates with yearling body mass and age at first reproduction in female chamois(Rughetti & Festa-Bianchet, 2011a), so that a negative trade-off between early horn growth and survival may indicate a reproductive cost(Bleu et al, 2014). The not statistically significant, albeit slightly negative, relationship between early horn growth and survival found in our study would thus suggest limited costs of early reproduction.Interestingly, recent studies did not find clear costs of reproduction at any age in female chamois, possibly owing to high individual heterogeneity in reproductive performance(Morin, Rughetti, Rioux-Pasquette, & Festa-Bianchet, 2016;Tettamanti, Grignolio, Filli, Apollonio, & Bize, 2015).…”

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confidence: 92%

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Does selection on horn length of males and females differ in protected and hunted populations of a weakly dimorphic ungulate?

Corlatti

Storch

Filli

et al. 2017

Ecology and Evolution

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Weaponry in ungulates may be costly to grow and maintain, and different selective pressures in males and females may lead to sex‐biased natural survival. Sexual differences in the relationship between weapon growth and survival may increase under anthropogenic selection through culling, for example because of trophy hunting. Selection on weaponry growth under different scenarios has been largely investigated in males of highly dimorphic ungulates, for which survival costs (either natural or hunting related) are thought to be greatest. Little is known, however, about the survival costs of weaponry in males and females of weakly dimorphic species. We collected information on horn length and age at death/shooting of 407 chamois Rupicapra rupicapra in a protected population and in two hunted populations with different hunting regimes, to explore sexual differences in the selection on early horn growth under contrasting selective pressures. We also investigated the variation of horn growth and body mass in yearling males (n = 688) and females (n = 539) culled in one of the hunted populations over 14 years. The relationship between horn growth and survival showed remarkable sexual differences under different evolutionary scenarios. Within the protected population, under natural selection, we found no significant trade‐off in either males or females. Under anthropogenic pressure, selection on early horn growth of culled individuals showed diametrically opposed sex‐biased patterns, depending on the culling regime and hunters’ preferences. Despite the selective bias between males and females in one of the hunted populations, we did not detect significant sex‐specific differences in the long‐term pattern of early growth. The relationship between early horn growth and natural survival in either sex might suggest stabilizing selection on horn size in chamois. Selection through culling can be strongly sex‐biased also in weakly dimorphic species, depending on hunters’ preferences and hunting regulations, and long‐term data are needed to reveal potential undesirable evolutionary consequences.

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Older conservatives: reproduction in female Alpine chamois (Rupicapra rupicapra) is increasingly risk-averse with age

Cited by 22 publications

References 85 publications

Long‐term studies of bighorn sheep and mountain goats reveal fitness costs of reproduction

Long‐term studies of bighorn sheep and mountain goats reveal fitness costs of reproduction

A negative association between horn length and survival in a weakly dimorphic ungulate

Does selection on horn length of males and females differ in protected and hunted populations of a weakly dimorphic ungulate?

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