The last decades have seen a burst in the number of empirical studies documenting reproductive ageing (i.e. the decrease in reproductive performance with increasing age). Age-specific declines in reproductive performance have thus been reported in a wide range of organisms (e.g. invertebrates, vertebrates, and humans) and under very diverse environmental conditions (e.g. in both captive and wild populations). Yet, despite this wave of studies, the full diversity of reproductive ageing patterns across the tree of life, as well as its evolutionary causes, remain to be deciphered, especially because reproduction is a complex sequential biological function that involves several life history traits. Getting a comprehensive picture of reproductive senescence necessitates the combination of (1) comparative analyses of trait-specific ageing patterns across species, (2) individual age-specific reproductive trajectories within and across populations monitored for long periods, and (3) experimental manipulations.
One salient challenge currently associated with the study of reproductive ageing is the need to embrace the sequential nature of the key biological function of reproduction. In both sexes, the outcome of a reproductive event (i.e. reproductive success measured as the number of offspring successfully produced after the period of parental care) involves a sequence of events (e.g. implantation success, birth success in females, pre- and post-copulatory competition in males) underpinned by phenotypic traits (size of secondary sexual traits) and physiological functions (e.g. milk production, spermatogenesis) that can all decline with increasing age. Moreover, studies of reproductive ageing through the lens of evolutionary biology have been mostly performed on females and despite strong implications in terms of fertility, our understanding of male reproductive senescence remains extremely limited. Therefore, how much natural and sexual selection have shaped the ageing patterns of reproductive traits in both sexes in a given environmental context is yet to be determined. Yet, gaining this knowledge is crucial to understand the evolution of reproductive ageing across and among species, as well as the occurrence of males and females’ reproductive diseases (e.g. testis, ovarian cancer) over the life course.
In this Research Topic, we are seeking to receive articles aiming to embrace the complexity of the reproductive ageing process through the lens of evolutionary biology, in both sexes, in species displaying contrasting life history strategies and living in a wide range of ecological conditions. We have identified a few lines of research that we would like to prioritize in this Research Topic:
• Determining the role of environmental conditions in shaping the age-specific decline in reproductive traits (e.g. milk production, sperm quality) and reproductive success
• Deciphering the asynchrony in the diversity of ageing trajectories among reproductive traits
• Embedding male reproductive ageing in the current framework proposed to explain the evolution of ageing (e.g. disposable soma theory, developmental theory of ageing)
• Shedding evolutionary and ecological lights on age-specific reproductive health and reproductive ageing in humans
• Quantifying the amount of individual heterogeneity in the onset and rate of reproductive ageing
• Identifying physiological and genetic markers of reproductive ageing in animal populations in the wild
• Exploring the evolutionary causes and consequences of the evolution of post-reproductive lifespan
The last decades have seen a burst in the number of empirical studies documenting reproductive ageing (i.e. the decrease in reproductive performance with increasing age). Age-specific declines in reproductive performance have thus been reported in a wide range of organisms (e.g. invertebrates, vertebrates, and humans) and under very diverse environmental conditions (e.g. in both captive and wild populations). Yet, despite this wave of studies, the full diversity of reproductive ageing patterns across the tree of life, as well as its evolutionary causes, remain to be deciphered, especially because reproduction is a complex sequential biological function that involves several life history traits. Getting a comprehensive picture of reproductive senescence necessitates the combination of (1) comparative analyses of trait-specific ageing patterns across species, (2) individual age-specific reproductive trajectories within and across populations monitored for long periods, and (3) experimental manipulations.
One salient challenge currently associated with the study of reproductive ageing is the need to embrace the sequential nature of the key biological function of reproduction. In both sexes, the outcome of a reproductive event (i.e. reproductive success measured as the number of offspring successfully produced after the period of parental care) involves a sequence of events (e.g. implantation success, birth success in females, pre- and post-copulatory competition in males) underpinned by phenotypic traits (size of secondary sexual traits) and physiological functions (e.g. milk production, spermatogenesis) that can all decline with increasing age. Moreover, studies of reproductive ageing through the lens of evolutionary biology have been mostly performed on females and despite strong implications in terms of fertility, our understanding of male reproductive senescence remains extremely limited. Therefore, how much natural and sexual selection have shaped the ageing patterns of reproductive traits in both sexes in a given environmental context is yet to be determined. Yet, gaining this knowledge is crucial to understand the evolution of reproductive ageing across and among species, as well as the occurrence of males and females’ reproductive diseases (e.g. testis, ovarian cancer) over the life course.
In this Research Topic, we are seeking to receive articles aiming to embrace the complexity of the reproductive ageing process through the lens of evolutionary biology, in both sexes, in species displaying contrasting life history strategies and living in a wide range of ecological conditions. We have identified a few lines of research that we would like to prioritize in this Research Topic:
• Determining the role of environmental conditions in shaping the age-specific decline in reproductive traits (e.g. milk production, sperm quality) and reproductive success
• Deciphering the asynchrony in the diversity of ageing trajectories among reproductive traits
• Embedding male reproductive ageing in the current framework proposed to explain the evolution of ageing (e.g. disposable soma theory, developmental theory of ageing)
• Shedding evolutionary and ecological lights on age-specific reproductive health and reproductive ageing in humans
• Quantifying the amount of individual heterogeneity in the onset and rate of reproductive ageing
• Identifying physiological and genetic markers of reproductive ageing in animal populations in the wild
• Exploring the evolutionary causes and consequences of the evolution of post-reproductive lifespan