future reproduction
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Author(s):  
Mirre J. P. Simons ◽  
Marion Sebire ◽  
Simon Verhulst ◽  
Ton G. G. Groothuis

Costs of reproduction shape the life-history evolution of investment in current and future reproduction and thereby aging. Androgens have been proposed to regulate the physiology governing these investments. Furthermore, androgens are hypothesized to play a central role in carotenoid-dependent sexual signaling, regulating how much carotenoids are diverted to ornamentation and away from somatic maintenance, increasing oxidative stress, and accelerating aging. We investigated these relationships in male three-spined stickleback in which we elevated 11-ketotestosterone and supplied vitamin E, an antioxidant, in a 2 × 2 design. Androgen elevation shortened the time stickleback maintained reproductive activities. We suspect that this effect is caused by 11-ketotestosterone stimulating investment in current reproduction, but we detected no evidence for this in our measurements of reproductive effort: nest building, body composition, and breeding coloration. Carotenoid-dependent coloration was even slightly decreased by 11-ketotestosterone elevation and was left unaffected by vitamin E. Red coloration correlated with life expectancy and reproductive capacity in a quadratic manner, suggesting overinvestment of the individuals exhibiting the reddest bellies. In contrast, blue iris color showed a negative relationship with survival, suggesting physiological costs of producing this aspect of nuptial coloration. In conclusion, our results support the hypothesis that androgens regulate investment in current versus future reproduction, yet the precise mechanisms remain elusive. The quadratic relationships between sexual signal expression and aspects of quality have wider consequences for how we view sexual selection on ornamentation and its relationship with aging.


Diversity ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 662
Author(s):  
Mark C. Belk ◽  
Peter J. Meyers ◽  
J. Curtis Creighton

The cost of reproduction hypothesis suggests that allocation to current reproduction constrains future reproduction. How organisms accrue reproductive costs and allocate energy across their lifetime may differ among species adapted to different resource types. We test this by comparing lifetime reproductive output, patterns of reproductive allocation, and senescence between two species of burying beetles, Nicrophorus marginatus and N. guttula, that differ in body size, across a range of carcass sizes. These two species of burying beetles maximized lifetime reproductive output on somewhat different–sized resources. The larger N. marginatus did better on large and medium carcasses while the smaller N. guttula did best on small and medium carcasses. For both species, reproduction is costly and reproduction on larger carcasses reduced lifespan more than reproduction on smaller carcasses. Carcass size also affected lifetime reproductive strategies. Each species’ parental investment patterns were consistent with terminal investment on carcasses on which they performed best (optimal carcass sizes). However, they exhibited reproductive restraint on carcass sizes on which they did not perform as well. Reproductive senescence occurred largely in response to carcass size. For both species, reproduction on larger carcasses resulted in more rapid senescence. These data suggest that whether organisms exhibit terminal investment or reproductive restraint may depend on type and amount of resources for reproduction.


Author(s):  
Garland R. Dahlke ◽  
Erika L. Lundy

Theobjective of this study was to evaluate the effects of metabolizable proteinand energy restriction during late gestation on the body condition score, bodyweight, and colostrum quality of fall calving cows, as well as their subsequentcalf performance. For this study, 48 multiparous Angus cows were used from theIowa State University-McNay Research and Demonstration Farm fall herd. 


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jorge García-Campa ◽  
Wendt Müller ◽  
Ester Hernández-Correas ◽  
Judith Morales

AbstractParents allocate resources to offspring to increase their survival and to maximize their own fitness, while this investment implies costs to their condition and future reproduction. Parents are hence expected to optimally allocate their resources. They should invest equally in all their offspring under good conditions, but when parental capacity is limited, parents should invest in the offspring with the highest probability of survival. Such parental favouritism is facilitated by the fact that offspring have evolved condition-dependent traits to signal their quality to parents. In this study we explore whether the parental response to an offspring quality signal depends on the intrinsic capacity of the parents, here the female. We first manipulated the intrinsic capacity of blue tit (Cyanistes caeruleus) females through lutein-supplementation during egg laying, and we subsequently blocked the UV/yellow reflectance of breast feathers on half of the nestlings in each brood. We did not find evidence that the female intrinsic capacity shaped parental feeding or sibling competition according to offspring UV/yellow colouration. However, nestling UV/yellow colour affected costly behavioural interactions in the form of prey-testings (when a parent places a prey item into a nestling’s gape but removes it again). In lutein-supplemented nests, fathers but not mothers favoured UV-blocked chicks by testing them less often, supporting previous results. Accordingly, in lutein-supplemented nests, UV-blocked nestlings gained more mass than their siblings, while in control nests we found the opposite effect and UV-blocked nestlings gained less. Our results emphasize that the prenatal environment shaped the role of offspring UV/yellow colour during certain family interactions and are indicative for sex-specific parental care strategies.


2021 ◽  
Vol 9 ◽  
Author(s):  
Wenxia Wang ◽  
Long Ma ◽  
Maaike A. Versteegh ◽  
Hua Wu ◽  
Jan Komdeur

Life-history theory predicts that increased resource allocation in current reproduction comes at the cost of survival and future reproductive fitness. In taxa with biparental care, each parent can adjust investment on current reproduction according to changes in their partner’s effort, but these adjustments may be different for males and females as they may have different reproductive strategies. Numerous theoretical and empirical studies have proposed the mechanism underlying such adjustments. In addition, the value of the brood or litter (brood size) has also been suggested to affect the amount of care through manipulation of brood size. While the two conditions have been studied independently, the impact of their interplay on potential sex-dependent future reproductive performance remains largely unknown. In this study, we simultaneously manipulated both care system (removal of either parent vs. no removal) and brood size in a burying beetle (Nicrophorus vespilloides) to understand their joint effect on reproductive allocation and trade-off between current and future reproduction. Our results show that males compensated for mate loss by significantly increasing the level of care regardless of brood size, while females exhibited such compensation only for small brood size. Additionally, with an increase in allocation to current reproduction, males showed decreased parental investment during the subsequent breeding event as a pair. These findings imply a dual influence of parental care system and brood size on allocation in current reproduction. Moreover, the impact of such adjustments on sex-dependent differences in future reproduction (parental care, larvae number, and average larval mass at dispersal) is also demonstrated. Our findings enhance the understanding of sex roles in parental investment and highlight their importance as drivers of reproductive allocation.


2021 ◽  
Vol 288 (1959) ◽  
pp. 20211279
Author(s):  
Xiangbo Guo ◽  
Paul A. Selden ◽  
Dong Ren

Maternal care benefits the survival and fitness of offspring, often at a cost to the mother's future reproduction, and has evolved repeatedly throughout the animal kingdom. In extant spider species, this behaviour is very common and has different levels and diverse forms. However, evidence of maternal care in fossil spiders is quite rare. In this study, we describe four Mid-Cretaceous (approx. 99 Ma) amber specimens from northern Myanmar with an adult female, part of an egg sac and some spiderlings of the extinct family Lagonomegopidae preserved, which suggest that adult lagonomegopid females probably built and then guarded egg sacs in their retreats or nests, and the hatched spiderlings may have stayed together with their mother for some time. The new fossils represent early evidence of maternal care in fossil spiders, and enhance our understanding of the evolution of this behaviour.


2021 ◽  
Author(s):  
Kelsey Q Wright

Objective: This study examines the schemas that women employed during the COVID-19 pandemic to make sense of their reproductive experiences. Background: Existing research on reproduction during epidemics suggests that there are variable population responses to periods of long-term social uncertainty and that individuals and couples can respond to these circumstances in unexpected ways. However, less is known about how individuals make sense of their reproductive experiences during periods of social upheaval.Method: Twenty-nine women aged 25-35 from a mid-sized Midwestern county were recruited and were interviewed about their experiences during the first eight months of the 2021 COVID-19 pandemic. They were asked about their daily lived experiences and about their partnership and reproductive goals during in-depth interviews. These interviews were transcribed and analyzed using thematic coding of the three main schemas that participants used to describe their reproductive experiences.Results: Participants used three main schemas to describe their reproductive experiences during the COVID-19 pandemic. Heteronormative schemas were used by many participants to articulate their commitment to a heteronormative aged-staged progression of life events. Affective schemas were used by participants, primarily those who were currently or recently pregnant, to express grief and loss over the relational experience of having a new baby. Medical schemas were expressed by most participants to describe feelings of fear and risk at real or imagined encounters with medical institutions during the pandemic.Conclusion: The schema that participants use to make sense of their reproductive experiences have real and enduring consequences for their current and future reproduction.


Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1498
Author(s):  
Saoirse McMahon ◽  
Magdalena Matzke ◽  
Cristina Tuni

Estimating costs of ejaculate production is challenging. Metabolic investment in ejaculates may come at the expense of other physiological functions and may negatively affect future reproduction and/or survival. These trade-offs are especially likely to occur under constrained resource pools (e.g., poor nutrition). Here, we investigated costs of ejaculate production via trade-offs in the field cricket Gryllus bimaculatus. We experimentally increased rates of ejaculate production, while keeping an unmanipulated group, in adult males kept at high and low feeding regimes and tested the effects of our treatments on (i) somatic maintenance (i.e., changes in male body mass), (ii) future reproduction (i.e., the likelihood of producing a spermatophore and the viability of its sperm), and (iii) lifetime survival and longevity. We predicted investment in ejaculates to impinge upon all measured responses, especially in low-fed individuals. Instead, we only found negative effects of food limitation, suggesting low or undetectable costs of spermatophore production. High mating rates may select for males to maximize their capacity of ejaculate production, making ejaculate traits less prone to trade-offs with other fitness-related life history traits. Nevertheless, males were impaired due to nutrient deficiency in producing viable ejaculates, suggesting condition-dependent costs for ejaculate production.


2021 ◽  
Vol 288 (1950) ◽  
Author(s):  
Jules Dezeure ◽  
Alice Baniel ◽  
Alecia Carter ◽  
Guy Cowlishaw ◽  
Bernard Godelle ◽  
...  

The evolutionary benefits of reproductive seasonality are often measured by a single-fitness component, namely offspring survival. Yet different fitness components may be maximized by different birth timings. This may generate fitness trade-offs that could be critical to understanding variation in reproductive timing across individuals, populations and species. Here, we use long-term demographic and behavioural data from wild chacma baboons ( Papio ursinus ) living in a seasonal environment to test the adaptive significance of seasonal variation in birth frequencies. We identify two distinct optimal birth timings in the annual cycle, located four-month apart, which maximize offspring survival or minimize maternal interbirth intervals (IBIs), by respectively matching the annual food peak with late or early weaning. Observed births are the most frequent between these optima, supporting an adaptive trade-off between current and future reproduction. Furthermore, infants born closer to the optimal timing favouring maternal IBIs (instead of offspring survival) throw more tantrums, a typical manifestation of mother–offspring conflict. Maternal trade-offs over birth timing, which extend into mother–offspring conflict after birth, may commonly occur in long-lived species where development from birth to independence spans multiple seasons. Our findings therefore open new avenues to understanding the evolution of breeding phenology in long-lived animals, including humans.


2021 ◽  
Author(s):  
Jorge García-Campa ◽  
Wendt Müller ◽  
Ester Hernández-Correas ◽  
Judith Morales

Abstract Parents allocate resources to offspring to increase their survival and to maximize their own fitness, while this investment implies costs to their condition and future reproduction. Parents are hence expected to optimally allocate their resources. They should invest equally in all their offspring under good conditions, but when parental capacity is limited, parents should invest in the offspring with the highest probability of survival. Such parental favouritism is facilitated by the fact that offspring have evolved condition-dependent traits to signal their quality to parents. In this study we explore whether the parental response to an offspring quality signal depends on the intrinsic capacity of the parents, here the female. We first manipulated the intrinsic capacity of blue tit (Cyanistes caeruleus) females through lutein-supplementation during egg laying, and we subsequently blocked the UV/yellow reflectance of breast feathers on half of the nestlings in each brood. However, we did not find evidence that the female intrinsic capacity shaped parental favouritism for offspring UV/yellow colouration, as there were no differences in parental feeding or sibling competition. However, we found that males were more responsive than females to nestling UV/yellow when rearing capacity was high, as indicated by the prey-testings (when a parent places a prey item into a nestling’s gape but removes it again). Furthermore, when considering a more integrative measure, offspring growth, we did find the expected interaction effect. In control nests, UV-blocked nestlings gained less body mass than their non-UV-blocked siblings, whereas in lutein-supplemented nests UV-blocked nestlings gained more mass than their siblings. Overall, our results emphasize the female’s environment at an early reproduction stage shaped the role of offspring UV/yellow during family interactions illustrating plasticity in parental feeding rules.


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