Reproductive Senescence in Two Lemur Lineages

Kappeler, Peter M.; Pethig, Leonie; Prox, Lea; Fichtel, Claudia

doi:10.3389/fevo.2022.894344

Cited by 4 publications

(2 citation statements)

References 82 publications

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“…Besides these, other factors could be predicted to influence SF ageing. For instance, evidence for reproductive ageing has been shown to be stronger in laboratory and captive animals compared to wild ones (Nussey et al, 2013;Zajitschek et al, 2020;Kappeler et al, 2022). Additionally, domestic animals, which were used in a majority of studies found in our systematic review, are kept in semi-controlled conditions and are killed off prior to reaching a senescent age (i.e., post their "prime").…”

Section: Factors That Could Influence Seminal Fluid Ageing Ratesmentioning

confidence: 99%

Timeless or tainted? The effects of male ageing on seminal fluid

Fricke

Sanghvi²,

Emery³

et al. 2023

Front. Ecol. Evol.

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Reproductive ageing can occur due to the deterioration of both the soma and germline. In males, it has mostly been studied with respect to age-related changes in sperm. However, the somatic component of the ejaculate, seminal fluid, is also essential for maintaining reproductive function. Whilst we know that seminal fluid proteins (SFPs) are required for male reproductive success across diverse taxa, age-related changes in SFP quantity and composition are little understood. Additionally, only few studies have explored the reproductive ageing of the tissues that produce SFPs, and the resulting reproductive outcomes. Here we provide a systematic review of studies addressing how advancing male age affects the production and properties of seminal fluid, in particular SFPs and oxidative stress, highlighting many open questions and generating new hypotheses for further research. We additionally discuss how declines in function of different components of seminal fluid, such as SFPs and antioxidants, could contribute to age-related loss of reproductive ability. Overall, we find evidence that ageing results in increased oxidative stress in seminal fluid and a decrease in the abundance of various SFPs. These results suggest that seminal fluid contributes towards important age-related changes influencing male reproduction. Thus, it is essential to study this mostly ignored component of the ejaculate to understand male reproductive ageing, and its consequences for sexual selection and paternal age effects on offspring.

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Section: Factors That Could Influence Seminal Fluid Ageing Ratesmentioning

confidence: 99%

Timeless or tainted? The effects of male ageing on seminal fluid

Fricke

Sanghvi²,

Emery³

et al. 2023

Front. Ecol. Evol.

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“…On the other hand, quadratic age could indicate reproductive senescence, suggesting a “prime” reproductive age around which infant survival may decrease due to factors like lack of dam experience (before prime age) or a decline in milk quality and quantity (after prime age; Tidière et al, 2018); this may suggest differing management strategies to promote infant survival around that prime age. Kappeler et al (2022) found evidence for reproductive senescence in wild red‐fronted lemurs ( Eulemur rufifrons ) and zoo‐housed red lemurs, and Tidière et al (2018) further demonstrated that infant survival of red‐ruffed and black‐and‐white ruffed lemurs initially increased with dam age, then began to decrease as the dam approached reproductive senescence. In some primate taxa, increased dam age was positively associated with infant mortality (de Visser et al, 2022) or the likelihood of stillbirths (Saiyed et al, 2018), while others showed reduced infant survival for both the youngest and oldest dams (Campos et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

Infant survival is significantly impacted by dam‐ and management‐related factors in zoo‐managed Eulemur populations

Robinson,

McDonald,

Stirk

et al. 2024

Zoo Biology

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Due to their potential impact on population growth, many studies have investigated factors affecting infant survival in mammal populations under human care. Here we used more than 30 years of Association of Zoos and Aquariums (AZA) studbook data and contraception data from the AZA Reproductive Management Center, along with logistic regression models, to investigate which factors affect infant survival in four Eulemur species managed as Species Survival Plans® in AZA. Across species, infant survival to 1 month ranged from 65% to 78%. Previous experience producing surviving offspring was positively correlated to infant survival in collared (Eulemur collaris), crowned (Eulemur coronatus), and mongoose (Eulemur mongoz) lemurs. Both dam age and previous use of contraception were negatively correlated to infant survival for collared lemurs, though our results suggest the latter may be confounded with other factors. Blue‐eyed black lemurs (Eulemur flavifrons) were affected by birth location, suggesting differences in husbandry that may affect infant survival. These results can be used to assist in reproductive planning or to anticipate the likelihood of breeding success. Population managers may also be able to focus their reproductive planning on younger dams or those with previous experience to predict successful births. Future studies should seek to determine what aspects of previous dam success are most important to infant survival, investigate sire‐related factors, and examine factors related to cause of death in infants that may lead to differential survival. Our hope is to present a framework that may be useful for investigating infant survival in other mammal species' breeding programs.

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Drivers and consequences of female reproductive competition in an egalitarian, sexually monomorphic primate

Prox

Fichtel

Kappeler

2023

Behav Ecol Sociobiol

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Even after the 150th anniversary of sexual selection theory, the drivers and mechanisms of female sexual selection remain poorly studied. To understand demographic circumstances favoring female-female competition, trade-offs with kin selection and interactions with male reproductive strategies, we investigated female evictions in redfronted lemurs (Eulemur rufifrons). Based on 24 years of demographic data of known individuals, we show that female redfronted lemurs target close female kin for forcible, permanent, and presumably lethal eviction, even though groups contain multiple unrelated males whose voluntary emigration actually mitigated the probability of future female evictions. Female eviction and male emigration were predicted by group size, but male emigration was primarily driven by a proportional increase of male rivals. Female evictions were more likely than male emigrations when there were more juvenile females in a group, but the identity of evicted females was not predicted by any intrinsic traits. While birth rates were reduced by the number of juvenile females, they were higher when there were more adult females in a group and in years with more rainfall. Early infant survival was reduced with increasing numbers of juvenile females, but variation in female lifetime reproductive success was not related to any of the predictors examined here. Thus, there seems to be a limit on female group size in this lemur species. More generally, our study demonstrates a balanced interplay between female reproductive competition, competition over group membership between both sexes, and kin selection, contributing new insights into the causes and consequences of female competition in animal societies. Significance statement The evolutionary causes of female competition in vertebrate societies remain poorly known. Evictions represent an extreme form of female competition because even close kin are evicted when same-sized unrelated males are theoretically also available as victims. We studied drivers and consequences of evictions in redfronted lemurs (Eulemur rufifrons) using 24 years of demographic data from multiple groups. We show that while voluntary male emigration mitigates the probability of future female evictions, females nonetheless appear to accept the fitness costs of evicting female kin. While group size seems to be the main driver of departures by either sex, the number of juvenile females present in groups is the key variable triggering eviction events as well as physiological responses that could be interpreted as female reproductive restraint. Our study therefore revealed that competition does trump cooperation under some circumstances in the intricate interplay between sexual selection and kin selection on females.

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Reproductive Senescence in Two Lemur Lineages

Cited by 4 publications

References 82 publications

Timeless or tainted? The effects of male ageing on seminal fluid

Timeless or tainted? The effects of male ageing on seminal fluid

Infant survival is significantly impacted by dam‐ and management‐related factors in zoo‐managed Eulemur populations

Drivers and consequences of female reproductive competition in an egalitarian, sexually monomorphic primate

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