Cognitive costs of reproduction: life‐history trade‐offs explain cognitive decline during pregnancy in women

2018 ◽  
Vol 94 (3) ◽  
pp. 1105-1115 ◽  
Author(s):  
Anna Ziomkiewicz ◽  
Szymon Wichary ◽  
Grazyna Jasienska
2007 ◽  
Vol 363 (1490) ◽  
pp. 375-398 ◽  
Author(s):  
John R Speakman

Life-history trade-offs between components of fitness arise because reproduction entails both gains and costs. Costs of reproduction can be divided into ecological and physiological costs. The latter have been rarely studied yet are probably a dominant component of the effect. A deeper understanding of life-history evolution will only come about once these physiological costs are better understood. Physiological costs may be direct or indirect. Direct costs include the energy and nutrient demands of the reproductive event, and the morphological changes that are necessary to facilitate achieving these demands. Indirect costs may be optional ‘compensatory costs’ whereby the animal chooses to reduce investment in some other aspect of its physiology to maximize the input of resource to reproduction. Such costs may be distinguished from consequential costs that are an inescapable consequence of the reproductive event. In small mammals, the direct costs of reproduction involve increased energy, protein and calcium demands during pregnancy, but most particularly during lactation. Organ remodelling is necessary to achieve the high demands of lactation and involves growth of the alimentary tract and associated organs such as the liver and pancreas. Compensatory indirect costs include reductions in thermogenesis, immune function and physical activity. Obligatory consequential costs include hyperthermia, bone loss, disruption of sleep patterns and oxidative stress. This is unlikely to be a complete list. Our knowledge of these physiological costs is currently at best described as rudimentary. For some, we do not even know whether they are compensatory or obligatory. For almost all of them, we have no idea of exact mechanisms or how these costs translate into fitness trade-offs.


1991 ◽  
Vol 69 (10) ◽  
pp. 2540-2547 ◽  
Author(s):  
Nathaniel T. Wheelwright ◽  
Joanna Leary ◽  
Caragh Fitzgerald

We investigated the effect of brood size on nestling growth and survival, parental survival, and future fecundity in tree swallows (Tachycineta bicolor) over a 4-year period (1987–1990) in an effort to understand whether reproductive trade-offs limit clutch size in birds. In addition to examining naturally varying brood sizes in a population on Kent Island, New Brunswick, Canada, we experimentally modified brood sizes, increasing or decreasing the reproductive burdens of females by two offspring. Unlike previous studies, broods of the same females were enlarged or reduced in up to 3 successive years in a search for evidence of cumulative costs of reproduction that might go undetected by a single brood manipulation. Neither observation nor experiment supported the existence of a trade-off between offspring quality and quantity, in contrast with the predictions of life-history theory. Nestling wing length, mass, and tarsus length were unrelated to brood size. Although differences between means were in the direction predicted, few differences were statistically significant, despite large sample sizes. Nestlings from small broods were no more likely to return as breeding adults than nestlings from large broods, but return rates of both groups were very low. Parental return rates were also independent of brood size, and there was no evidence of a negative effect of brood size on future fecundity (laying date, clutch size). Reproductive success, nestling size, and survival did not differ between treatments for females whose broods were manipulated in successive years. Within the range of brood sizes observed in this study, the life-history costs of feeding one or two additional nestlings in tree swallows appear to be slight and cannot explain observed clutch sizes. Costs not measured in this study, such as the production of eggs or postfledging parental care, may be more important in limiting clutch size in birds.


2021 ◽  
Author(s):  
Janelle Badger ◽  
W. Don Bowen ◽  
Nell den Heyer ◽  
Greg A. Breed

Life history variation is thought to be mainly a result of energetic trade-offs among fitness components; however, detecting these trade-offs in natural populations has yielded mixed results. Individual quality and environmental variation may mask expected relationships among fitness components because some higher quality individuals may be able to acquire more resources and invest more in all functions. Thus, life history variation may be more affected by variation in individual quality than varying strategies to resolve energetic trade-offs, e.g. costs of reproduction. Here, we investigated whether variation in female quality or costs of reproduction is a larger factor in shaping differences in life history trajectories by assessing the relationship between survival and individual reproductive performance using a 32-year longitudinal data set of repeated reproductive measurements from 273 individually marked, known-aged female grey seals (Halichoerus grypus) from the Sable Island breeding colony. We defined individual reproductive performance using two traits: reproductive frequency (a female's probability of breeding) and provisioning performance (provisions given to young measured by offspring mass), computed using mixed effects models separately for (1) all reproductive events, and (2) an age-class specific reproductive investment. Individual differences contributed a large portion of the variance in reproductive traits, with individuals displaying a range in individual reproductive frequencies from 0.45 to 0.94, and a range of average pup weaning masses from 34.9 kg to 61.8 kg across their lifetime. We used a Cormack-Jolly-Seber open-population model to estimate the effect of these reproductive performance traits on adult survival probability. Our approach estimated a positive relationship between reproductive performance and survival, where individuals that consistently invest well in their offspring survive longer. The best supported model estimated survival as a function of age-class specific provisioning performance, where late-life performance was quite variable and had the greatest impact on survival, possibly indicating individual variation in senescence. There was no evidence to support a trade-off in reproductive performance and survival at the individual level. These results suggest that in grey seals, individual quality is a stronger driver in life history variation than varying strategies to mitigate trade-offs among fitness components.


2020 ◽  
Author(s):  
M.I. Mäenpää ◽  
P.T. Smiseth

AbstractLife-history trade-offs between the number and size of offspring produced, and the costs of reproduction on future reproduction and survival can all be affected by different levels of parental effort. Because of these trade-offs the parents and the offspring have different optima for the amount of care given to the current brood, which leads to a conflict between parents and offspring. The offspring, as well as the parents, have the ability to affect parental effort, and thus changes in offspring traits have the potential to cause reproductive costs on the parents. Here, we used a repeated cross-fostering design to manipulate offspring demand during juvenile development in the burying beetle Nicrophorus vespilloides to examine whether responding to offspring begging incurs reproductive costs to the parent. After a manipulated first reproductive event, we gave each experimental female, that had been exposed to different levels of offspring demand, a chance to breed again, and monitored their survival. We found that larval demand influences the trade-off between the size and number of offspring produced, but has no impact on the reproductive costs through future reproduction or survival of the parent. The parents do, however, pay an overall fecundity cost for the general success of their first broods, but this cost was not related to the changes in the levels of larval begging. Other traits, including survival showed no costs of reproduction. Survival and the number of larvae successfully raised in the second broods correlated positively, indicating differences in the individual quality of the parents.


2021 ◽  
Vol 288 (1948) ◽  
Author(s):  
Elena Hamann ◽  
Susana M. Wadgymar ◽  
Jill T. Anderson

Investment in current reproduction can reduce future fitness by depleting resources needed for maintenance, particularly under environmental stress. These trade-offs influence life-history evolution. We tested whether climate change alters the future-fitness costs of current reproduction in a large-scale field experiment of Boechera stricta (Brassicaceae). Over 6 years, we simulated climate change along an elevational gradient in the Rocky Mountains through snow removal, which accelerates snowmelt and reduces soil water availability. Costs of reproduction were greatest in arid, lower elevations, where high initial reproductive effort depressed future fitness. At mid-elevations, initial reproduction augmented subsequent fitness in benign conditions, but pronounced costs emerged under snow removal. At high elevation, snow removal dampened costs of reproduction by prolonging the growing season. In most scenarios, failed reproduction in response to resource limitation depressed lifetime fecundity. Indeed, fruit abortion only benefited high-fitness individuals under benign conditions. We propose that climate change could shift life-history trade-offs in an environment-dependent fashion, possibly favouring early reproduction and short lifespans in stressful conditions.


2019 ◽  
Author(s):  
Gretchen F. Wagner ◽  
Emeline Mourocq ◽  
Michael Griesser

Biparental care systems are a valuable model to examine conflict, cooperation, and coordination between unrelated individuals, as the product of the interactions between the parents influences the fitness of both individuals. A common experimental technique for testing coordinated responses to changes in the costs of parental care is to temporarily handicap one parent, inducing a higher cost of providing care. However, dissimilarity in experimental designs of these studies has hindered interspecific comparisons of the patterns of cost distribution between parents and offspring. Here we apply a comparative experimental approach by handicapping a parent at nests of five bird species using the same experimental treatment. In some species, a decrease in care by a handicapped parent was compensated by its partner, while in others the increased costs of care were shunted to the offspring. Parental responses to an increased cost of care primarily depended on the total duration of care that offspring require. However, life history pace (i.e., adult survival and fecundity) did not influence parental decisions when faced with a higher cost of caring. Our study highlights that a greater attention to intergenerational trade-offs is warranted, particularly in species with a large burden of parental care. Moreover, we demonstrate that parental care decisions may be weighed more against physiological workload constraints than against future prospects of reproduction, supporting evidence that avian species may devote comparable amounts of energy into survival, regardless of life history strategy.


2017 ◽  
Vol 49 (6) ◽  
pp. 783 ◽  
Author(s):  
Yan WANG ◽  
Zhenchao LIN ◽  
Bowen HOU ◽  
Shijin SUN

Author(s):  
Maren N. Vitousek ◽  
Laura A. Schoenle

Hormones mediate the expression of life history traits—phenotypic traits that contribute to lifetime fitness (i.e., reproductive timing, growth rate, number and size of offspring). The endocrine system shapes phenotype by organizing tissues during developmental periods and by activating changes in behavior, physiology, and morphology in response to varying physical and social environments. Because hormones can simultaneously regulate many traits (hormonal pleiotropy), they are important mediators of life history trade-offs among growth, reproduction, and survival. This chapter reviews the role of hormones in shaping life histories with an emphasis on developmental plasticity and reversible flexibility in endocrine and life history traits. It also discusses the advantages of studying hormone–behavior interactions from an evolutionary perspective. Recent research in evolutionary endocrinology has provided insight into the heritability of endocrine traits, how selection on hormone systems may influence the evolution of life histories, and the role of hormonal pleiotropy in driving or constraining evolution.


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