A demographic and evolutionary analysis of maternal effect senescence (original) (raw)
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Reproductive senescence: new perspectives in the wild
Biological reviews of the Cambridge Philosophical Society, 2017
According to recent empirical studies, reproductive senescence, the decline in reproductive success with increasing age, seems to be nearly ubiquitous in the wild. However, a clear understanding of the evolutionary causes and consequences of reproductive senescence is still lacking and requires new and integrative approaches. After identifying the sequential and complex nature of female reproductive senescence, we show that the relative contributions of physiological decline and alterations in the efficiency of parental care to reproductive senescence remain unknown and need to be assessed in the light of current evolutionary theories of ageing. We demonstrate that, although reproductive senescence is generally studied only from the female viewpoint, age-specific female reproductive success strongly depends on male-female interactions. Thus, a reduction in male fertilization efficiency with increasing age has detrimental consequences for female fitness. Lastly, we call for investiga...
The evolution of senescence in fish
Mechanisms of Ageing and …, 2002
Fish are over-represented among the vertebrates that are known to live over 100 years. Such trends in maximum longevity suggest that fish also experience delayed senescence relative to other vertebrates. Most applications of evolutionary theory suggest that the extrinsic mortality rate, or mortality that is attributable to external factors like disease or predation, is the major factor that shapes the evolution of senescence, so that the only way to evolve delayed senescence is to experience lower rates of extrinsic mortality. We propose instead that fish are more inclined to evolve delayed senescence because they have indeterminate growth and, as a consequence, have the capacity for a substantial increase in fecundity with age. It is thus the combined effects of the expectation of survival and fecundity that shape the evolution of senescence, as originally proposed by . We also argue that fish share many of the same general mechanisms that shape the evolution of senescence in other vertebrates. We support this argument with statistical analyses of life history data that show the same patterns of correlation among traits as seen in birds and mammals.
Maternal age effects on offspring lifespan and reproduction vary within a species
bioRxiv (Cold Spring Harbor Laboratory), 2023
Across diverse taxa, offspring from older mothers have decreased lifespan and fitness. Little is known about whether such maternal age effects vary among genotypes for a given species, however. We compared maternal age effects among four strains of rotifers in the Brachionus plicatilis species complex. For each strain, we measured lifespan, reproductive schedule, and lifetime reproductive output of offspring produced by young, middle-aged, and old mothers. We found unexpected variability among strains in the magnitude and direction of maternal age effects on offspring life history traits. In one strain, offspring of young mothers lived 20% longer than offspring of old mothers, whereas there were no significant effects of maternal age on lifespan for the other strains. Across strains, advanced maternal age had positive effects, negative effects, or no effect on lifetime reproductive output. For all but one strain, older mothers produced offspring that had higher maximum daily reproduction early in life. Maternal age effects appear to be genetically determined traits, not features of life history strategy or due to accumulation of age-related damage in the germline. Investigating intraspecific variability is critical for understanding the ubiquity of maternal age effects and their role in the evolution of life history and aging.
An integrative view of senescence in nature
Functional Ecology, 2020
Senescence—the decline in age‐specific contribution to fitness with increasing age—has been widely investigated in evolutionary ecology. A tremendous amount of detailed empirical analyses have now revealed the widespread occurrence of demographic senescence (i.e. both actuarial and reproductive senescence) and have started to identify factors (e.g. environmental conditions) that modulate its timing and intensity, both within and across species. In this special feature, we have built on this flourishing work to highlight several axes of research that would benefit from more integrative and multidisciplinary approaches. Several contributions compiled in this special feature emphasize that our understanding of senescence remains taxonomically limited, mostly focused on birds and mammals, and is therefore not representative of the biological diversity displayed across the tree of life. In line with this observation, the influence of some peculiar lifestyles (e.g. involving sociality or ...
How can evolutionary theory accommodate recent empirical results on organismal senescence?
Theory in Biosciences, 2007
According to a prominent recent report, guppies collected from sites lacking predators are inferior in every aspect of their life history profile to those evolved in other, nearby sites with predators present. This is an exception to two classical predictions of evolutionary theory: that low extrinsic mortality should be associated with longer life span, and that higher fertility should be associated with shorter life span. Some theorists have tried to accommodate this and other anomalous results within the standard framework, but we argue that the exceptions they carve out do not explain the results at hand. In fact, the findings suggest that population regulation has been selected at the group level, though this is a mechanism that most theorists regard with suspicion. We conclude by relating the present result to other experiments that seem to point in the same direction.
New model systems for studying the evolutionary biology of aging: Crustacea
Genetica, 1993
Progress in any area of biology has generally required work on a variety of organisms. This is true because particular species often have characteristics that make them especially useful for addressing specific questions. Recent progress in studying the evolutionary biology of senescence has been made through the use of new species, such as Caenorhabditis elegans and Drosophila melanogaster, because of the ease of working with them in the laboratory and because investigators have used theories for the evolution of aging as a basis for discovering the underlying mechanisms.
On the Age-Specific Selection and the Emergence of Extensive Lifespan beyond Menopause
2019
Extensive post reproductive lifespan (PRLS) is observed only in a few species, such as humans or resident killer whales, and its origin is under debate. Hypotheses like mother-care and grandmothercare invoke strategies of investment-provision to one's descendants to enhance one's overall reproductive success-to explain PRLS. The contribution of an investment strategy varies with the age of the caregiver, as the number of care-receiving descendant changes with age. Here we simulated an agent based model, which is sensitive to age-specific selection, to examine how the investment strategies in different hypotheses affect survival and reproduction across different stages of life. We found that extensive PRLS emerges if we combine multiple investment strategies, including grandmothercare but not mother-care, which allow an individual to have an increasing contribution as it ages. We also found that, if mother-care is further introduced to the PRLS-enabling strategies, it will let contribution at mid-life to substitute contribution at late life, which consequently terminates extensive PRLS.