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1
LEE, JI HO. "Big Data, Data Mining and Temporary Reproduction." Journal of Intellectual Property 8, no. 4 (2013): 93–125. http://dx.doi.org/10.34122/jip.2013.12.8.4.93.
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Reekie, Edward G., Sonya Budge, and Jennifer L. Baltzer. "The shape of the trade-off function between reproduction and future performance in Plantago major and Plantago rugelii." Canadian Journal of Botany 80, no. 2 (2002): 140–50. http://dx.doi.org/10.1139/b01-146.
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There is a paucity of data describing the nature of the trade-off function between reproduction and future performance. Most studies implicitly assume it is a linear function such that allocation of resources to reproduction results in a proportional decline in future survival and reproduction. We reanalyse data from a field experiment with half-sib families of Plantago major L. that suggests this relationship is in fact curvilinear. Low levels of reproductive investment had relatively little impact on future performance and higher levels of investment had a larger impact. To explain this curvilinear pattern, we conducted an experiment to examine the effect of incremental increases in reproductive investment on rates of resource uptake in P. major and Plantago rugelii Decne. Results suggest that, because of differences in the resource requirements of vegetative versus reproductive tissues, reproduction will have little effect on growth, providing that the limiting resources are required in greater quantities for vegetative as compared with reproductive tissues. These results are in accord with a curvilinear trade-off function between reproduction and future performance and provide an explanation for the maintenance of sexual reproduction in species where seed production may contribute minimally to fitness in the short term.Key words: reproductive cost, resource allocation, life-history theory, nitrogen uptake, reproductive photosynthesis, Plantago major, Plantago rugelii.
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Fautin, Daphne Gail. "Reproduction of Cnidaria." Canadian Journal of Zoology 80, no. 10 (2002): 1735–54. http://dx.doi.org/10.1139/z02-133.
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Empirical and experimental data on cnidarian reproduction show it to be more variable than had been thought, and many patterns that had previously been deduced hold up poorly or not at all in light of additional data. The border between sexual and asexual reproduction appears to be faint. This may be due to analytical tools being insufficiently powerful to distinguish between the two, but it may be that a distinction between sexual and asexual reproduction is not very important biologically to cnidarians. Given the variety of modes by which it is now evident that asexual reproduction occurs, its ecological and evolutionary implications have probably been underestimated. Appropriate analytical frameworks and strategies must be developed for these morphologically simple animals, in which sexual reproduction may not be paramount, that during one lifetime may pass though two or more phases differing radically in morphology and ecology, that may hybridize, that are potentially extremely long-lived, and that may transmit through both sexual and asexual reproduction mutations arising in somatic tissue. In cnidarians, perhaps more than in any other phylum, reproductive attributes have been used to define taxa, but they do so at a variety of levels and not necessarily in the way they have conventionally been considered. At the species level, in Scleractinia, in which these features have been most studied, taxa defined on the basis of morphology, sexual reproduction, and molecular characters may not coincide; there are insufficient data to determine if this is true throughout the phylum. At the class level, transverse fission occurs in members of all three major taxa but is rare outside Scyphozoa, the group of which it is considered characteristic (pending more research, its absence in Cubozoa should be ascribed to poor knowledge). Understanding the role of transverse fission in the ecology and reproductive biology of hydrozoans and anthozoans could shed light on scyphozoan evolutionary history, and elucidating its morphogenesis in all groups is essential to determining if it is homologous across the classes. Only by comparing aspects of reproduction among cnidarians of various taxa will idiosyncratically adaptive strategies be distinguished from reproductive characters that reflect evolution and so are phylogenetically informative.
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Warner, Daniel A., David A. W. Miller, Anne M. Bronikowski, and Fredric J. Janzen. "Decades of field data reveal that turtles senesce in the wild." Proceedings of the National Academy of Sciences 113, no. 23 (2016): 6502–7. http://dx.doi.org/10.1073/pnas.1600035113.
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Lifespan and aging rates vary considerably across taxa; thus, understanding the factors that lead to this variation is a primary goal in biology and has ramifications for understanding constraints and flexibility in human aging. Theory predicts that senescence—declining reproduction and increasing mortality with advancing age—evolves when selection against harmful mutations is weaker at old ages relative to young ages or when selection favors pleiotropic alleles with beneficial effects early in life despite late-life costs. However, in many long-lived ectotherms, selection is expected to remain strong at old ages because reproductive output typically increases with age, which may lead to the evolution of slow or even negligible senescence. We show that, contrary to current thinking, both reproduction and survival decline with adult age in the painted turtle, Chrysemys picta, based on data spanning >20 y from a wild population. Older females, despite relatively high reproductive output, produced eggs with reduced hatching success. Additionally, age-specific mark–recapture analyses revealed increasing mortality with advancing adult age. These findings of reproductive and mortality senescence challenge the contention that chelonians do not age and more generally provide evidence of reduced fitness at old ages in nonmammalian species that exhibit long chronological lifespans.
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Weibel, Chelsea J., Jenny Tung, Susan C. Alberts, and Elizabeth A. Archie. "Accelerated reproduction is not an adaptive response to early-life adversity in wild baboons." Proceedings of the National Academy of Sciences 117, no. 40 (2020): 24909–19. http://dx.doi.org/10.1073/pnas.2004018117.
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In humans and other long-lived species, harsh conditions in early life often lead to profound differences in adult life expectancy. In response, natural selection is expected to accelerate the timing and pace of reproduction in individuals who experience some forms of early-life adversity. However, the adaptive benefits of reproductive acceleration following early adversity remain untested. Here, we test a recent version of this theory, the internal predictive adaptive response (iPAR) model, by assessing whether accelerating reproduction following early-life adversity leads to higher lifetime reproductive success. We do so by leveraging 48 y of continuous, individual-based data from wild female baboons in the Amboseli ecosystem in Kenya, including prospective, longitudinal data on multiple sources of nutritional and psychosocial adversity in early life; reproductive pace; and lifetime reproductive success. We find that while early-life adversity led to dramatically shorter lifespans, individuals who experienced early adversity did not accelerate their reproduction compared with those who did not experience early adversity. Further, while accelerated reproduction predicted increased lifetime reproductive success overall, these benefits were not specific to females who experienced early-life adversity. Instead, females only benefited from reproductive acceleration if they also led long lives. Our results call into question the theory that accelerated reproduction is an adaptive response to both nutritional and psychosocial sources of early-life adversity in baboons and other long-lived species.
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Barve, Sahas, Christina Riehl, Eric L. Walters, Joseph Haydock, Hannah L. Dugdale, and Walter D. Koenig. "Lifetime reproductive benefits of cooperative polygamy vary for males and females in the acorn woodpecker ( Melanerpes formicivorus )." Proceedings of the Royal Society B: Biological Sciences 288, no. 1957 (2021): 20210579. http://dx.doi.org/10.1098/rspb.2021.0579.
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Cooperative breeding strategies lead to short-term direct fitness losses when individuals forfeit or share reproduction. The direct fitness benefits of cooperative strategies are often delayed and difficult to quantify, requiring data on lifetime reproduction. Here, we use a longitudinal dataset to examine the lifetime reproductive success of cooperative polygamy in acorn woodpeckers ( Melanerpes formicivorus ), which nest as lone pairs or share reproduction with same-sex cobreeders. We found that males and females produced fewer young per successful nesting attempt when sharing reproduction. However, males nesting in duos and trios had longer reproductive lifespans, more lifetime nesting attempts and higher lifetime reproductive success than those breeding alone. For females, cobreeding in duos increased reproductive lifespan so the lifetime reproductive success of females nesting in duos was comparable to those nesting alone and higher than those nesting in trios. These results suggest that for male duos and trios, reproductive success alone may provide sufficient fitness benefits to explain the presence of cooperative polygamy, and the benefits of cobreeding as a duo in females are higher than previously assumed. Lifetime individual fitness data are crucial to reveal the full costs and benefits of cooperative polygamy.
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Zarutskie, Paul. "Collection of clinical data on assisted reproduction." Women's Health Issues 6, no. 3 (1996): 132–34. http://dx.doi.org/10.1016/1049-3867(96)85673-8.
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Guzick, David S., James Boles, and Richard Schadle. "Data base management system for assisted reproduction." Journal of In Vitro Fertilization and Embryo Transfer 7, no. 5 (1990): 236–40. http://dx.doi.org/10.1007/bf01129525.
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Lakman, Irina A. "Spatial model of reproduction on panel data." Economics and the Mathematical Methods 57, no. 2 (2021): 34. http://dx.doi.org/10.31857/s042473880011338-0.
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Glass, K., G. N. Mercer, H. Nishiura, E. S. McBryde, and N. G. Becker. "Estimating reproduction numbers for adults and children from case data." Journal of The Royal Society Interface 8, no. 62 (2011): 1248–59. http://dx.doi.org/10.1098/rsif.2010.0679.
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We present a method for estimating reproduction numbers for adults and children from daily onset data, using pandemic influenza A(H1N1) data as a case study. We investigate the impact of different underlying transmission assumptions on our estimates, and identify that asymmetric reproduction matrices are often appropriate. Under-reporting of cases can bias estimates of the reproduction numbers if reporting rates are not equal across the two age groups. However, we demonstrate that the estimate of the higher reproduction number is robust to disproportionate data-thinning. Applying the method to 2009 pandemic influenza H1N1 data from Japan, we demonstrate that the reproduction number for children was considerably higher than that of adults, and that our estimates are insensitive to our choice of reproduction matrix.
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Weber, Alexandra Anh-Thu, Sabine Stöhr, and Anne Chenuil. "Genetic data, reproduction season and reproductive strategy data support the existence of biological species in Ophioderma longicauda." Comptes Rendus Biologies 337, no. 10 (2014): 553–60. http://dx.doi.org/10.1016/j.crvi.2014.07.007.
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Helle, Samuli. "Selection bias in studies of human reproduction-longevity trade-offs." Proceedings of the Royal Society B: Biological Sciences 284, no. 1868 (2017): 20172104. http://dx.doi.org/10.1098/rspb.2017.2104.
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A shorter lifespan as a potential cost of high reproductive effort in humans has intrigued researchers for more than a century. However, the results have been inconclusive so far and despite strong theoretical expectations we do not currently have compelling evidence for the longevity costs of reproduction. Using Monte Carlo simulation, it is shown here that a common practice in human reproduction-longevity studies using historical data (the most relevant data sources for this question), the omission of women who died prior to menopausal age from the analysis, results in severe underestimation of the potential underlying trade-off between reproduction and lifespan. In other words, assuming that such a trade-off is expressed also during reproductive years, the strength of the trade-off between reproduction and lifespan is progressively weakened when women dying during reproductive ages are sequentially and non-randomly excluded from the analysis. In cases of small sample sizes (e.g. few hundreds of observations), this selection bias by reducing statistical power may even partly explain the null results commonly found in this field. Future studies in this field should thus apply statistical approaches that account for or avoid selection bias in order to recover reliable effect size estimates between reproduction and longevity.
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Søvik, Guldborg, and Hans Petter Leinaas. "Adult survival and reproduction in an arctic mite, Ameronothrus lineatus (Acari, Oribatida): effects of temperature and winter cold." Canadian Journal of Zoology 81, no. 9 (2003): 1579–88. http://dx.doi.org/10.1139/z03-113.
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Survival and reproduction of an arctic population of Ameronothrus lineatus were studied at four constant temperatures (5, 10, 15, and 21 °C). By simulating winters in the laboratory, an adult population was followed through 3 "years". Increasing temperatures reduced adult longevity. Females survived longer than males. A temperature of 15 °C was the most favourable for reproduction, with highest larviposition rate and reproductive output. Lifetime reproductive output was also high at 10 °C, while lower numbers of larvae at 21 °C indicated the beginning of heat stress. Comparison with field data showed that the reproductive performance at 15 °C corresponded to reproduction in a natural population experiencing a mean temperature of 89 °C, suggesting a positive effect of daily temperature fluctuations. A simulated winter with freezing temperatures increased male survival and positively affected all aspects of reproduction the following laboratory summer.
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Anshoria, Azharuddin, Tri Nurhajati, and Budi Utomo. "Cases of Reproduction Disorder in Beef Cattle of Modo District, Lamongan in 2015." KnE Life Sciences 3, no. 6 (2017): 727. http://dx.doi.org/10.18502/kls.v3i6.1203.
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The aim of this research is to discover how several factors – namely feed, age, and parity might contribute toward cases of reproduction disorder in beef cattle of Modo District, Lamongan in 2015. Materials used in this research are data obtained from five villages, showing 340 out of 3.331 animals exhibiting reproduction disorder symptoms. The method used for this research is the survey method, and primary and secondary data were obtained. Primary data were obtained from field surveys of interviewing farmers, local animal health officials and artificial inseminators. Secondary data were obtained from examination for reproduction disorder in beef cattle by the Livestock and Animal Health Service of Lamongan. The data obtained were then tabulated and analyzed with the regression tree method using Windows Statistical Product and Service (SPSS) to determine the main cause of reproduction disorder in beef cattle of Modo District, Lamongan in 2015. The results show that feed is the main factor contributing to reproduction disorder in beef cattle of Modo District, Lamongan, while age and parity showed a less significant role. Key words: Beef cattle, feed, age, parity, reproductive disorders
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García, María C., Miguel López, Clara V. Alvarez, Felipe Casanueva, Manuel Tena-Sempere, and Carlos Diéguez. "Role of ghrelin in reproduction." Reproduction 133, no. 3 (2007): 531–40. http://dx.doi.org/10.1530/rep-06-0249.
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Ghrelin, the endogenous ligand of GH secretagogue receptor type 1a, has emerged as a pleiotropic modulator of diverse biological functions, including energy homeostasis and, lately reproduction. Here, we review recent reports evaluating the reproductive effects and sites of action of ghrelin, with particular emphasis regarding its role as a molecule integrating reproductive function and energy status. Data gleaned from rodent studies clearly show that besides having direct gonadal effects, ghrelin may participate in the regulation of gonadotropin secretion and it may influence the timing of puberty. In addition, experimental data showing that ghrelin and/or its receptor are expressed in normal human ovary and testis as well as in human ovarian and testicular tumors raise the possibility that the ghrelin system may be involved in the control of cell proliferation in these tumors. We propose that ghrelin either acting as an endocrine and/or paracrine signal may play a major role in the endocrine network that integrates energy balance and reproduction.
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Garrott, Robert A., Thomas C. Eagle, and Edward D. Plotka. "Age-specific reproduction in feral horses." Canadian Journal of Zoology 69, no. 3 (1991): 738–43. http://dx.doi.org/10.1139/z91-106.
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Two age-specific reproduction schedules were constructed for feral horses (Equus caballus) on the basis of lactation status of 14 788 females captured during herd reduction programs and pregnancy rates of 667 horses determined by serum progesterone assays. The probability of detecting lactation progressively decreased for females captured further from the foaling season, indicating that these data resulted in substantial underestimates of true foaling rates. A third reproductive schedule was, therefore, constructed on the basis of a subsample of 1144 horses captured immediately after the foaling season in June. Characteristics common across all three data sets were first reproduction at age 2, an increase in the proportion of females foaling through age 6, highest foaling rates from 6 to 15 years, and a gradual decrease in foaling rates of females >15 years. Variability in the proportion of reproductively active females in each age-class was detected among populations and among years within a population; however, the general trend was high reproductive rates, with 80–90% of the prime-age females foaling. The reproduction model suggested by L. L. Eberhardt, provided a close mathematical approximation of the observed age-specific changes in foaling rates, providing a useful tool for the construction of reproduction schedules required for age-structured population models.
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Harrison, J. L. "Data on the reproduction of some Malayan mammals." Proceedings of the Zoological Society of London 125, no. 2 (2009): 445–60. http://dx.doi.org/10.1111/j.1096-3642.1955.tb00609.x.
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Fairchild, Mark D., and Garrett M. Johnson. "Color-appearance reproduction: Visual data and predictive modeling." Color Research & Application 24, no. 2 (1999): 121–31. http://dx.doi.org/10.1002/(sici)1520-6378(199904)24:2<121::aid-col7>3.0.co;2-i.
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Manchuk, John G., Ryan M. Barnett, and Clayton V. Deutsch. "Reproduction of secondary data in projection pursuit transformation." Stochastic Environmental Research and Risk Assessment 31, no. 10 (2016): 2585–605. http://dx.doi.org/10.1007/s00477-016-1363-y.
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Kumar, Sunil, and Anupama Sharma. "Cadmium toxicity: effects on human reproduction and fertility." Reviews on Environmental Health 34, no. 4 (2019): 327–38. http://dx.doi.org/10.1515/reveh-2019-0016.
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Abstract Background Cadmium (Cd) is a non-essential toxic heavy metal, an environmental toxicant, and toxic at a low concentration, and it has no known beneficial role in the human body. Its exposure induces various health impairments including hostile reproductive health. Objective The present review discusses the information on exposure to Cd and human reproductive health impairments including pregnancy or its outcome with respect to environmental and occupational exposure. Methods The present review provides current information on the reproductive toxic potential of Cd in humans. The data were collected using various websites and consulting books, reports, etc. We have included recent data which were published from 2000 onward in this review. Results Cd exposure affects human male reproductive organs/system and deteriorates spermatogenesis, semen quality especially sperm motility and hormonal synthesis/release. Based on experimental and human studies, it also impairs female reproduction and reproductive hormonal balance and affects menstrual cycles. Based on the literature, it might be concluded that exposure to Cd at low doses has adverse effects on both human male and female reproduction and affects pregnancy or its outcome. Further, maternal prenatal Cd exposure might have a differential effect on male and female offspring especially affecting more female offspring. Hence, efforts must be made to prevent exposure to Cd. Conclusion Cd affects both male and female reproduction, impairs hormone synthesis/regulation and deteriorates pregnancy rate or its outcome even at lower doses.
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Humtsoe, L. Nzano, Sabitry Bordoloi, Annemarie Ohler, and Stéphane Grosjean. "Natural History and Reproductive Data of Kurixalus yangi (Anura: Rhacophoridae) in Nagaland, India." Russian Journal of Herpetology 27, no. 5 (2020): 257–74. http://dx.doi.org/10.30906/1026-2296-2020-27-5-257-274.
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The genus Kurixalus Ye, Fei et Dubois, 1999 (Rhacophoridae Hoffman, 1932) is a small and taxonomically difficult group of treefrogs for which biological and reproductive data are missing for most of the species. A recent study of the K. odontotarsus species group (Yu et al., 2017a) revealed numerous undescribed lineages. Among them a lineage comprising specimens from Myanmar and western Yunnan, China was described as K. yangi. We report here the presence of a population of this species from Nagaland, North East India, identified by DNA barcoding of the 16S rRNA gene and morphology. A pair of adults found in amplexus is described morphologically. Data on reproduction and developmental mode were until now unknown for the continental species of this genus. Observation of reproduction in the field of K. yangi from Nagaland provided us data on its reproductive activity including spawning behavior and reproductive mode, and details on the larval developmental timing. The tadpole of this species is described for the first time including buccal anatomy. Adults are commonly found in the stumps of bamboo internodes. They breed in forest ponds, temporary rain pools or rain water tanks. Breeding activity starts from mid-April till late part of July. Unpigmented eggs measure 2.4 – 2.7 mm and are laid underwater. Under natural conditions (air temperature 18 – 30°C, water temperature 12 – 24°C), the frog complete its larval life cycle in 47 days. The tadpole shows a «classical» pond-dwelling morphology and reproductive mode. These reproductive data are compared to the Taiwanese species for which the developmental mode is well known and the evolution of the reproductive modes within the genus is discussed.
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Richards, J. S., M. A. Sladek, and G. J. Lee. "Cumulative reproductive performance effect on overall lifetime productivity in Merino sheep." Animal Production Science 58, no. 8 (2018): 1470. http://dx.doi.org/10.1071/an17794.
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Reproduction is an important driver of profitability in commercial sheep flocks. Historically, Merino flocks have been run with a fixed age structure, ignoring individual merit and casting for age at a specific age. More recently, research has focussed on utilising the variation within age groups by keeping productive older ewes longer and culling less productive ewes earlier. Previous studies have also examined the effect of age on reproduction and the impact of reproduction status on productivity, but little research has been conducted on cumulative effects of reproductive performance on later productivity, reproduction and health. The present study examined the impact of higher lifetime reproduction on other key production and fitness traits in older ewes run under commercial conditions. Data were collected from two commercial wool-producing properties in the South West Slopes and the Central West Plains of New South Wales during 2009–2011. Reproduction, fleece measurements, bodyweight and condition and dental health were recorded during the study. The results showed that age had a bigger effect on productivity and dental health than did cumulative lifetime reproduction. Environment and genetics determined the level of impact, with minimal loss in productivity from increased age of animals occurring in the South West Slopes flock, whereas the Central West Plains flock would appear to require closer monitoring of productivity as ewes aged. The data collected did not allow separation of the genetic and environmental influences within the study. Retaining animals with a higher reproductive performance past normal culling age does not necessarily result in reduction of productivity or ewe health, but this must be monitored.
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Bates, Shannon M. "Anticoagulation and in vitro fertilization and ovarian stimulation." Hematology 2014, no. 1 (2014): 379–86. http://dx.doi.org/10.1182/asheducation-2014.1.379.
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Abstract Assisted reproductive technology is widely used to treat couples affected by infertility. Complications associated with assisted reproduction include venous thromboembolism, ovarian hyperstimulation syndrome, and recurrent implantation failure. It has also been proposed that thrombophilia may be associated with an increased likelihood of these events. Although data are limited, antithrombotic therapy is frequently used to enhance the likelihood of successful assisted reproduction. This chapter reviews the risks of venous and arterial thromboembolism associated with assisted reproduction, as well as available data regarding the impact of thrombophilia on the risks of thromboembolism and failure of implantation. The role of antithrombotic therapy in reducing the likelihood of these events, along with recommendations from various guidelines, are also discussed.
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Lee, G. J., K. D. Atkins, and M. A. Sladek. "Heterogeneity of lifetime reproductive performance, its components and associations with wool production and liveweight of Merino ewes." Animal Production Science 49, no. 7 (2009): 624. http://dx.doi.org/10.1071/an09013.
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The heterogeneity in lifetime (2–6 years of age) reproductive performance within three research flocks maintained at the Agricultural Research Centre, Trangie, in central-western New South Wales, was used to establish the potential to improve flock reproductive performance by identifying performance segments for either selection or for differential management. The data comprised a total of 32 716 records from 7322 ewes, collected over the period from 1977 to 2003. Within each of the flocks, there were large differences (P < 0.001) in lifetime net reproduction rate, and each of its components (fertility, fecundity and lamb survival), between each of the net reproduction rate quartiles. The difference in net reproduction between the ewes in the top quartile and those in the bottom quartile was equivalent to an additional lamb per ewe annually. These differences in reproduction rate between the quartiles were not related to pre-joining liveweight or condition score. Higher reproductive rates were associated with a cost to clean fleece weight, although the estimated effects on fibre diameter were small. Opportunities to use this variation to improve reproduction rates are discussed and include retaining high-performing ewes longer in the breeding flock, removing poor performers and targeting management interventions towards ewes that will yield the largest responses.
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Grazer, Vera M., and Oliver Y. Martin. "Investigating Climate Change and Reproduction: Experimental Tools from Evolutionary Biology." Biology 1, no. 2 (2012): 411–38. http://dx.doi.org/10.3390/biology1020411.
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It is now generally acknowledged that climate change has wide-ranging biological consequences, potentially leading to impacts on biodiversity. Environmental factors can have diverse and often strong effects on reproduction, with obvious ramifications for population fitness. Nevertheless, reproductive traits are often neglected in conservation considerations. Focusing on animals, recent progress in sexual selection and sexual conflict research suggests that reproductive costs may pose an underestimated hurdle during rapid climate change, potentially lowering adaptive potential and increasing extinction risk of certain populations. Nevertheless, regime shifts may have both negative and positive effects on reproduction, so it is important to acquire detailed experimental data. We hence present an overview of the literature reporting short-term reproductive consequences of exposure to different environmental factors. From the enormous diversity of findings, we conclude that climate change research could benefit greatly from more coordinated efforts incorporating evolutionary approaches in order to obtain cross-comparable data on how individual and population reproductive fitness respond in the long term. Therefore, we propose ideas and methods concerning future efforts dealing with reproductive consequences of climate change, in particular by highlighting the advantages of multi-generational experimental evolution experiments.
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Broussard, David R., F. Stephen Dobson, and J. O. Murie. "The effects of capital on an income breeder: evidence from female Columbian ground squirrels." Canadian Journal of Zoology 83, no. 4 (2005): 546–52. http://dx.doi.org/10.1139/z05-044.
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To maximize fitness, organisms must optimally allocate resources to reproduction, daily metabolic maintenance, and survival. We examined multiple years of live-trapping and observational data from a known-aged population of female Columbian ground squirrels, Spermophilus columbianus (Ord, 1815), to determine the influences of stored resources and daily resource income on the reproductive investments of females. We predicted that because yearling females were not fully grown structurally while producing their first litter, they would rely exclusively on income for reproduction, while reproductive investment in older females (≥2 years of age) would be influenced by both stored resources (capital) and daily income. Results from path analysis indicated that both yearlings and older females were income breeders. However, initial capital indirectly influenced investment in reproduction of yearling and older females. Females with the greatest initial capital maintained high body masses while investing relatively more income in reproduction. By considering influences of both capital and income, important relationships can be revealed between these resources and their influence on life histories.
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Pestis, V. K., L. V. Golubets, and A. S. Deshko. "Assisted reproductive technologies in cattle reproduction and selection." Proceedings of the National Academy of Sciences of Belarus. Agrarian Series 57, no. 2 (2019): 192–203. http://dx.doi.org/10.29235/1817-7204-2019-57-2-192-203.
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In vitro technology is one of the most dynamically developing and more and more stable biotechnological methods today accelerating selection, intensifying reproductive and genetic potential of breeding animals, allowing to increase breeding young animals production by one champion cow up to 5–10 calves per year, reduce generation interval and significantly accelerate process of updating and qualitative improvement of livestock. However, obtaining oocytes competent for in vitro development is one of the critical factors determining success of the method and depending on a number of biological and technical factors. This paper presents results of studies on effect of biological factors of direct and indirect impact on efficiency of obtaining oocytes in the system of transvaginal aspiration for the first time conducted in the Republic of Belarus. Yield of excellent and good quality oocytes increased during aspiration during the luteal phase of estrous cycle and remained almost unchanged during aspiration into the follicular phase. Presence of follicles with diameter over 8 mm in the ovaries during aspiration reduced yield of excellent and good quality oocytes averagely by 9.4 percentage points. Removing the dominant follicle 72 hours prior to aspiration allowed increasing the number of aspirated follicles by 41 %, and yield of oocytes – by 22.9 %. Microstimulation of ovaries prior to aspiration by follicle-stimulating hormones FSG-super and Plusset increased efficiency of aspiration in terms of the main indicators by 19.2–45.9 %. Follicular cyst or persistent corpus luteum in one of the ovaries reduced both quantitative and qualitative indicators of aspiration. The data obtained are of practical importance for development of technology for in vitro embryo production in the system of transvaginal aspiration of oocytes which will help to accelerate breeding process and increase efficiency of breeding work in livestock production in general.Acknowledgments. The research was conducted within the two state research programs: “Biotechnology”, subprogram “Development of biological science, biological education and biological industry for 2007–2011 and for the period up to 2020”, “High technologies and equipment for 2016-2020”, subprogram 1 “Innovative biotechnologies–2020”.
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Lee, G. J., M. A. Sladek, S. Hatcher, and J. S. Richards. "Using partial records to identify productive older ewes to retain in the breeding flock to increase the flock net reproduction rate." Animal Production Science 54, no. 10 (2014): 1631. http://dx.doi.org/10.1071/an14435.
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The reproductive performance of 7286 ewes from three Merino genetic resource flocks maintained in the central-western region of New South Wales was used to compare the use of fertility and fecundity information and net reproduction information whether recorded early (at 2 and 3 years of age) or later in life (at 4 and 5 years of age) with lifetime performance (at 2–6 years of age) as alternative selection criteria to identify productive older ewes to retain in the breeding flock. While the lifetime net reproduction rate is the best indicator of a ewe’s reproductive performance in later life, producers basing their selection decisions on pregnancy scanning data, which provides information on both fertility and fecundity, can improve the net reproduction rate of their flock by 2% regardless of the base reproduction rate. Despite little difference in likely flock reproduction rates between using early or later life scanning information as the selection criteria, early life performance is the best choice for commercial producers because it provides scope for eliminating twice-dry ewes from the breeding flock early in life, especially when combined with udder examination at marking.
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Matsui, Ayaka, Yuki Yokokura, and Seiichiro Katsura. "Dynamic Data Reproduction of Contact Environment with State Transition." IEEJ Journal of Industry Applications 2, no. 1 (2013): 22–29. http://dx.doi.org/10.1541/ieejjia.2.22.
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Kordyum, E. L. "Plant reproduction systems in microgravity: Experimental data and hypotheses." Advances in Space Research 21, no. 8-9 (1998): 1111–20. http://dx.doi.org/10.1016/s0273-1177(97)00198-1.
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HAZEMOTO, Jumpei, Makoto OKUMURA, and Makoto TSUKAI. "Reproduction of Net Passenger Trips from Gross Traffic Data." INFRASTRUCTURE PLANNING REVIEW 21 (2004): 83–89. http://dx.doi.org/10.2208/journalip.21.83.
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Delignette-Muller, Marie Laure, Christelle Lopes, Philippe Veber, and Sandrine Charles. "Statistical Handling of Reproduction Data for Exposure-Response Modeling." Environmental Science & Technology 48, no. 13 (2014): 7544–51. http://dx.doi.org/10.1021/es502009r.
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Yamaguchi, Hiroyuki, Yasushi Tatehira, Kenji Akiyama, and Yukio Kobayashi. "Data compression and depth shape reproduction of stereoscopic images." Systems and Computers in Japan 22, no. 12 (1991): 53–64. http://dx.doi.org/10.1002/scj.4690221205.
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De Bond, Julie-Ann P., and Jeremy T. Smith. "Kisspeptin and energy balance in reproduction." REPRODUCTION 147, no. 3 (2014): R53—R63. http://dx.doi.org/10.1530/rep-13-0509.
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Kisspeptin is vital for the neuroendocrine regulation of GNRH secretion. Kisspeptin neurons are now recognized as a central pathway responsible for conveying key homeostatic information to GNRH neurons. This pathway is likely to mediate the well-established link between energy balance and reproductive function. Thus, in states of severely altered energy balance (either negative or positive), fertility is compromised, as isKiss1expression in the arcuate nucleus. A number of metabolic modulators have been proposed as regulators of kisspeptin neurons including leptin, ghrelin, pro-opiomelanocortin (POMC), and neuropeptide Y (NPY). Whether these regulate kisspeptin neurons directly or indirectly will be discussed. Moreover, whether the stimulatory role of leptin on reproduction is mediated by kisspeptin directly will be questioned. Furthermore, in addition to being expressed in GNRH neurons, the kisspeptin receptor (Kiss1r) is also expressed in other areas of the brain, as well as in the periphery, suggesting alternative roles for kisspeptin signaling outside of reproduction. Interestingly, kisspeptin neurons are anatomically linked to, and can directly excite, anorexigenic POMC neurons and indirectly inhibit orexigenic NPY neurons. Thus, kisspeptin may have a direct role in regulating energy balance. Although data fromKiss1rknockout and WT mice found no differences in body weight, recent data indicate that kisspeptin may still play a role in food intake and glucose homeostasis. Thus, in addition to regulating reproduction, and mediating the effect of energy balance on reproductive function, kisspeptin signaling may also be a direct regulator of metabolism.
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Liu, Quan-Hui, Marco Ajelli, Alberto Aleta, Stefano Merler, Yamir Moreno, and Alessandro Vespignani. "Measurability of the epidemic reproduction number in data-driven contact networks." Proceedings of the National Academy of Sciences 115, no. 50 (2018): 12680–85. http://dx.doi.org/10.1073/pnas.1811115115.
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The basic reproduction number is one of the conceptual cornerstones of mathematical epidemiology. Its classical definition as the number of secondary cases generated by a typical infected individual in a fully susceptible population finds a clear analytical expression in homogeneous and stratified mixing models. Along with the generation time (the interval between primary and secondary cases), the reproduction number allows for the characterization of the dynamics of an epidemic. A clear-cut theoretical picture, however, is hardly found in real data. Here, we infer from highly detailed sociodemographic data two multiplex contact networks representative of a subset of the Italian and Dutch populations. We then simulate an infection transmission process on these networks accounting for the natural history of influenza and calibrated on empirical epidemiological data. We explicitly measure the reproduction number and generation time, recording all individual-level transmission events. We find that the classical concept of the basic reproduction number is untenable in realistic populations, and it does not provide any conceptual understanding of the epidemic evolution. This departure from the classical theoretical picture is not due to behavioral changes and other exogenous epidemiological determinants. Rather, it can be simply explained by the (clustered) contact structure of the population. Finally, we provide evidence that methodologies aimed at estimating the instantaneous reproduction number can operationally be used to characterize the correct epidemic dynamics from incidence data.
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Waynforth, David. "Life-history theory, chronic childhood illness and the timing of first reproduction in a British birth cohort." Proceedings of the Royal Society B: Biological Sciences 279, no. 1740 (2012): 2998–3002. http://dx.doi.org/10.1098/rspb.2012.0220.
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Life-history theoretical models show that a typical evolutionarily optimal response of a juvenile organism to high mortality risk is to reach reproductive maturity earlier. Experimental studies in a range of species suggest the existence of adaptive flexibility in reproductive scheduling to maximize fitness just as life-history theory predicts. In humans, supportive evidence has come from studies comparing neighbourhoods with different mortality rates, historical and cross-cultural data. Here, the prediction is tested in a novel way in a large ( n = 9099), longitudinal sample using data comparing age at first reproduction in individuals with and without life-expectancy-reducing chronic disease diagnosed during childhood. Diseases selected for inclusion as chronic illnesses were those unlikely to be significantly affected by shifting allocation of effort away from reproduction towards survival; those which have comparatively large effects on mortality and life expectancy; and those which are not profoundly disabling. The results confirmed the prediction that chronic disease would associate with early age at first reproduction: individuals growing up with a serious chronic disease were 1.6 times more likely to have had a first child by age 30. Analysis of control variables also confirmed past research findings on links between being raised father-absent and early pubertal development and reproduction.
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Karsten, S., R. Röhe, V. Schulze, H. Looft, and E. Kalm. "Genetische Beziehungen zwischen individueller Futteraufnahme während der Eigenleistungsprüfung und Fruchtbarkeitsmerkmalen beim Schwein." Archives Animal Breeding 43, no. 5 (2000): 451–62. http://dx.doi.org/10.5194/aab-43-451-2000.
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Abstract. Title of the paper. Genetic association between individual feed intake during Performance test and reproductions traits in pigs The present study deals with the estimation of genetic correlations between Performance test traits measured in boars and reproduction traits of their offspring (sibs) of two purebred lines. Performance traits were individual feed intake (FI) recorded by electronic feeder, feed conversion ratio (FCR), average daily gain (ADG) and backfat thickness (BF). Reproduction traits were number of total piglets born (NBT) and born alive (NBA) Data of 4869 young boars, Performance tested between April 1992 and May 1997 and data of 9710 primiparous sows farrowed between June 1994 to November 1998, were observed. Heritabilities of Performance traits recorded on Station were in line 03 (line 04) h2 = 0.24 (0.33), 0.33 (0.33), 0.23 (0.32) and 0.47 (0.53) for FI, ADG FCR and BF, respectively. Heritabilities of reproduction traits such as NBT, NBA were in line 03 (line 04) h2 = 0 05 (0.08) and 0.05 (0.06), respectively. Genetic correlation between individual feed intake and reproduction traits ranged between rg = 0.12 and 0.27. Undesirable genetic correlations were found between reproduction traits and feed efficiency (rg = 0.13 to 0.44), backfat thickness (rg = 0.07 to 0.25) and partly average daily gain (rg = −010 to 0.09). Line 04 showed lowest magnitude of feed intake and highest genetic antagonism between production and reproduction traits. It is suggested that feed intake capacity is a limiting factor for reproduction in line 04 and genetic antagonism between production and reproduction traits increases with reduction in feed intake.
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Robertson, Ellen P., Robert J. Fletcher, Christopher E. Cattau, et al. "Isolating the roles of movement and reproduction on effective connectivity alters conservation priorities for an endangered bird." Proceedings of the National Academy of Sciences 115, no. 34 (2018): 8591–96. http://dx.doi.org/10.1073/pnas.1800183115.
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Movement is important for ecological and evolutionary theory as well as connectivity conservation, which is increasingly critical for species responding to environmental change. Key ecological and evolutionary outcomes of movement, such as population growth and gene flow, require effective dispersal: movement that is followed by successful reproduction. However, the relative roles of movement and postmovement reproduction for effective dispersal and connectivity remain unclear. Here we isolate the contributions of movement and immigrant reproduction to effective dispersal and connectivity across the entire breeding range of an endangered raptor, the snail kite (Rostrhamus sociabilis plumbeus). To do so, we unite mark–resight data on movement and reproduction across 9 years and 27 breeding patches with an integrated model that decomposes effective dispersal into its hierarchical levels of movement, postmovement breeding attempt, and postmovement reproductive success. We found that immigrant reproduction limits effective dispersal more than movement for this endangered species, demonstrating that even highly mobile species may have limited effective connectivity due to reduced immigrant reproduction. We found different environmental limitations for the reproductive component of effective dispersal compared with movement, indicating that different conservation strategies may be needed when promoting effective dispersal rather than movement alone. We also demonstrate that considering immigrant reproduction, rather than movement alone, alters which patches are the most essential for connectivity, thereby changing conservation priorities. These results challenge the assumption that understanding movement alone is sufficient to infer connectivity and highlight that connectivity conservation may require not only fostering movement but also successful reproduction of immigrants.
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BATRA, T. R., A. J. LEE, and A. J. McALLISTER. "RELATIONSHIPS OF REPRODUCTION TRAITS, BODY WEIGHT AND MILK YIELD IN DAIRY CATTLE." Canadian Journal of Animal Science 66, no. 1 (1986): 53–65. http://dx.doi.org/10.4141/cjas86-007.
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The relationships between reproduction traits, body weight and milk yield were investigated using data from 1611 heifers and 733 cows from two lines of the National Cooperative Dairy Cattle Breeding Project. The data were analyzed separately for heifers and cows within lines using a mixed linear model containing fixed effects for station, year of birth, season of birth and random effect of sires. Heritability estimates and genetic correlations were estimated by a paternal half-sib analysis. Heritability estimates for heifer and cow reproduction traits ranged between 0 and 26% while those of body weights at calving and 112 d postpartum and milk yield ranged from 24 to 43%. Heifers with difficult calving had a higher incidence of retained placenta than those with normal calving. Phenotypic correlations between heifer reproduction traits and milk yield during first lactation were small. High milk production in cows was associated with longer calving interval. Phenotypic correlations between heifer's and cow's reproduction traits were small. Difficult calving in heifers impairs reproductive performance after calving resulting in greater number of days from calving to first and last breeding and leading to a longer calving interval. Key words: Reproduction traits, heifers, cows, milk yield, dairy cattle
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Fledderjohann, Jasmine, and Celia Roberts. "Missing men, missing infertility: The enactment of sex/gender in surveys in low- and middle-income countries." Population Horizons 15, no. 2 (2018): 66–87. http://dx.doi.org/10.1515/pophzn-2018-0003.
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Abstract Although reproduction involves (at least) two sexed bodies, men are often missing from in/fertility research. Surveys such as the widely-used Demographic and Health Surveys (DHS) engage in often unintentional yet highly consequential practices of gendering. Here we identify two processes through which surveys have the potential to render male infertility invisible: defining the population at risk of infertility in an exclusionary way; and designing survey instruments to select out some groups/issues. Compiling information about survey samples and inclusion criteria in the DHS, and combining this with a qualitative examination of instrument design, we identify areas of men’s invisibility across time and place. While inclusion of men in DHS samples has increased over time, some men (e.g. single and divorced, transgender) remain missing in many survey settings. This is problematic from a reproductive justice perspective. Survey results, which both reflect and contribute to men’s invisibility, are widely used as an evidence-base for family and population policies. Moreover, reproductive health services are only made available to those whose reproductive health needs are recognized; men’s exclusion from the reproductive discourse contributes to the stratification of reproduction. Men’s underrepresentation in in/fertility data also reinforces the notion that reproduction is a woman’s domain, and so contributes to a system that places responsibility for reproduction on women. It is vital to explore how gender is enacted or ‘done’ in such research.
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Gore, Ellie, and Genevieve LeBaron. "Using social reproduction theory to understand unfree labour." Capital & Class 43, no. 4 (2019): 561–80. http://dx.doi.org/10.1177/0309816819880787.
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Most scholarship within social reproduction theory focuses on women’s paid and unpaid care and domestic work, typically within the global North. Rarely has social reproduction theory grappled with unfree labour in commodity supply chains, particularly in the global South. However, these labour relations also involve gendered power relations that cut across the productive and reproductive realms of the economy, which can be illuminated by social reproduction theory analysis. In this article, we reflect on how social reproduction theory can be used to make sense of unfree labour’s role in global supply chains, expanding its geographical scope and the forms of labour exploitation encompassed within it. Conceptually, we harness the insights of social reproduction theory, and Jeffrey Harrod and Robert W Cox’s work on ‘unprotected work’ in the global economy to examine how gendered power relations shape patterns of unfree labour. Empirically, we analyse interview and survey data collected among cocoa workers in Ghana through LeBaron’s Global Business of Forced Labour project. We argue that social reproduction theory can move global supply chain scholarship beyond its presently economistic emphasis on the productive sphere and can shed light into the overlaps between social oppression, economic exploitation, and social reproduction.
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Green, Jonathan P., Michael A. Cant, and Jeremy Field. "Using social parasitism to test reproductive skew models in a primitively eusocial wasp." Proceedings of the Royal Society B: Biological Sciences 281, no. 1789 (2014): 20141206. http://dx.doi.org/10.1098/rspb.2014.1206.
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Remarkable variation exists in the distribution of reproduction (skew) among members of cooperatively breeding groups, both within and between species. Reproductive skew theory has provided an important framework for understanding this variation. In the primitively eusocial Hymenoptera, two models have been routinely tested: concessions models, which assume complete control of reproduction by a dominant individual, and tug-of-war models, which assume on-going competition among group members over reproduction. Current data provide little support for either model, but uncertainty about the ability of individuals to detect genetic relatedness and difficulties in identifying traits conferring competitive ability mean that the relative importance of concessions versus tug-of-war remains unresolved. Here, we suggest that the use of social parasitism to generate meaningful variation in key social variables represents a valuable opportunity to explore the mechanisms underpinning reproductive skew within the social Hymenoptera. We present a direct test of concessions and tug-of-war models in the paper wasp Polistes dominulus by exploiting pronounced changes in relatedness and power structures that occur following replacement of the dominant by a congeneric social parasite. Comparisons of skew in parasitized and unparasitized colonies are consistent with a tug-of-war over reproduction within P. dominulus groups, but provide no evidence for reproductive concessions.
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Dobson, F. Stephen, and Pierre Jouventin. "Testing Williams’ prediction: reproductive effort versus residual reproductive value (RRV)." Canadian Journal of Zoology 88, no. 9 (2010): 900–904. http://dx.doi.org/10.1139/z10-055.
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Williams (1966; Am. Nat. 100(916): 687–690) furthered R.A. Fisher’s concept of reproductive value by breaking it into two components: (1) current reproduction and (2) residual reproductive value (RRV, the summed product of survival and reproduction over the rest of the lifespan). He predicted a negative correlation of measures of these two components among species, and this prediction led in part to the idea of trade-offs in life-history theory. We tested Williams’ prediction with 24 species of albatrosses and petrels (order Procellariiformes), species with a great range of body sizes and all laying only one egg at a time (like humans, highly iteroparous). Two measures of reproductive investment were not negatively correlated with RRV. Adjusting data for body mass and phylogeny resulted in significant positive associations. In addition, any measure of annual parental allocation to reproduction (once adjusted for body size) should give a positive association with RRV as shown by a simple simulation model that assumes a highly iteroparous life cycle. Under such life cycles, Williams’ prediction confounds the positive influence of reproduction on both current investment and RRV. Principles of life-history theory, however, do not require re-evaluation, as this particular prediction can in at least some cases be internally inconsistent.
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Nichols, Hazel J., Kevin Arbuckle, Karen Fullard, and William Amos. "Why don’t long-finned pilot whales have a widespread postreproductive lifespan? Insights from genetic data." Behavioral Ecology 31, no. 2 (2020): 508–18. http://dx.doi.org/10.1093/beheco/arz211.
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Abstract In a handful of mammals, females show an extended postreproductive lifespan (PRLS), leading to questions over why they spend a substantial portion of their lifespan nonreproductive. Theoretical and empirical studies suggest that PRLS may evolve when 1) demographic patterns lead to increasing local relatedness as females age, and 2) females come into reproductive competition with their daughters, as these conditions lead to high relative benefits of helping kin versus reproducing in later life. However, evolutionary pathways to PRLS are poorly understood and empirical studies are scarce. Here, we use a dataset of 1522 individuals comprising 22 pods to investigate patterns of reproduction and relatedness in long-finned pilot whales Globicephala melas; a toothed whale without species-wide PRLS. We find a similar relatedness structure to whales with PRLS: pods appear composed of related matrilines, and relatedness of females to their pod increases with age, suggesting that this species could benefit from late-life help. Furthermore, females with a large number of philopatric adult daughters are less likely to reproduce, implying intergenerational reproductive competition between females. This suggests that individuals may display a plastic cessation of reproduction, switching to investing in existing offspring when they come into competition with their daughters. To the best of our knowledge, this is the first time such a relationship has been described in relation to PRLS, and it raises questions about whether this represents a step towards evolving PRLS or is a stable alternative strategy to widespread postreproductive periods.
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Caramaschi, Érica Pellegrini, and Marcelo Fulgêncio Guedes Brito. "REPRODUÇÃO DE PEIXES DE RIACHO: ESTADO DA ARTE, MÉTODOS E PERSPECTIVAS." Oecologia Australis 25, no. 02 (2021): 323–43. http://dx.doi.org/10.4257/oeco.2021.2502.07.
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Stream fish reproduction is still poorly studied in natural environments, especially in the Neotropical region. In this chapter, we recollect some characteristics of fish reproduction and some questions to guide current research, as: Does sexual dimorphism occur in the species? Which is the mode of reproduction? When and where does the species reproduce? Which environmental factors trigger reproductive events? When does the reproductive life begin? Which is the fecundity? Most of these questions can be answered when we have many specimens available, captured at different periods of the year, measured, weighed and dissected following appropriate protocols. Obtained data represent life history traits that allow to categorize the species in reproductive styles related to parental care and to determine their accordance to models of reproductive strategy associated with the predictability of environmental conditions. We highlight some aspects to be considered in current and future field and lab procedures, such as the recognition of sexual dimorphisms, the importance of naturalistic observation and lab procedures. We draw attention to the advances in studies on reproductive modalities in fish groups well represented in streams, such as inseminating characiforms and viviparous cyprinodontiforms. Finally, we highlight gaps, urgencies, and current perspectives for studies on the reproduction of stream fish, with emphasis on the need for basic studies of species biology, on the importance for building theoretical references and for the conservation of stream habitats in all Brazilian biomes.
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Helle, Samuli, and Virpi Lummaa. "A trade-off between having many sons and shorter maternal post-reproductive survival in pre-industrial Finland." Biology Letters 9, no. 2 (2013): 20130034. http://dx.doi.org/10.1098/rsbl.2013.0034.
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A bias in reproduction towards sons, which are energetically more costly than daughters, has been suggested to shorten parental lifespan, but previous results have been mixed. Reproductive costs should be most evident in low rather than high resource settings, and are not expected to be severe in men, because women pay higher direct costs of reproduction. We, therefore, used demographic data from pre-industrial Finland to investigate whether the number of sons and daughters born affected their parents’ post-reproductive survival and whether this was related to parent's resource availability. Irrespective of access to resources, mothers, but not fathers, with many sons suffered from reduced post-reproductive survival, and this association decreased as mothers aged. Our results provide evidence that Finnish mothers traded long post-reproductive lifespan for giving birth to many sons.
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Barclay, Robert M. R., Joel Ulmer, Cameron J. A. MacKenzie, et al. "Variation in the reproductive rate of bats." Canadian Journal of Zoology 82, no. 5 (2004): 688–93. http://dx.doi.org/10.1139/z04-057.
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In many respects, bats have relatively slow life histories. However, the reproductive rate of bats (i.e., the proportion of females that reproduce in any breeding season) has not been critically examined. We compiled data on the reproductive rates of bats to test predictions based on life-history theory. Among 257 samples from 103 species, reproductive rate varied considerably and was typically under 100%. Temperate-zone species had significantly lower and more variable reproductive rates than did tropical species. Reproductive rate also varied among families, with species in the Vespertilionidae having particularly high rates. As predicted based on life-history theory, reproductive rate was negatively correlated with longevity, and among vespertilionids, species with larger litters had higher reproductive rates. Thus, the data suggest that bats have relatively slow reproductive rates and, as in other life-history traits, fall at the "slow" end of the fast–slow life-history continuum found among mammals. Female bats, especially those in temperate regions, appear to adjust their allocation of resources to reproduction, and at times forego reproduction, perhaps in relation to their body condition, prey availability, and weather conditions.
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Vézina, François, and Katrina G. Salvante. "Behavioral and physiological flexibility are used by birds to manage energy and support investment in the early stages of reproduction." Current Zoology 56, no. 6 (2010): 767–92. http://dx.doi.org/10.1093/czoolo/56.6.767.
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Abstract Interest in phenotypic flexibility has increased dramatically over the last decade, but flexibility during reproduction has received relatively little attention from avian scientists, despite its possible impact on fitness. Because most avian species maintain atrophied reproductive organs when not active, reproduction in birds requires major tissue remodeling in preparation for breeding. Females undergo rapid (days) recrudescence and regression of their reproductive organs at each breeding attempt, while males grow their organs ahead of time at a much slower rate (weeks) and may maintain them at maximal size throughout the breeding season. Reproduction is associated with significant metabolic costs. Egg production leads to a 22%-27% increase in resting metabolic rate (RMR) over non-reproductive values. This is partly due to the activity of the oviduct, an organ that may allow females to adjust reproductive investment by modulating egg size and quality. In males, gonadal recrudescence may lead to a 30% increase in RMR, but the data are inconsistent and general conclusions regarding energetic costs of reproduction in males will require more research. Recent studies on captive female zebra finches describe the impacts of these costs on daily energy budgets and highlight the strategies used by birds to maintain their investment in reproduction when energy is limited. Whenever possible, birds use behavioral flexibility as a first means of saving energy. Decreasing locomotor activity saves energy during challenges such as egg production or exposure to cold temperatures and is an efficient way to buffer variation in individual daily energy budgets. However, when behavioral flexibility is not possible, birds must rely on flexibility at the physiological level to meet energy demands. In zebra finches breeding in the cold, this results in a reduced pace of laying, likely due to down-regulation of both reproductive and non-reproductive function, allowing females to defend minimal egg size and maintain reproductive success. More research involving a range of species in captive and free-living conditions is needed to determine how phenotypic flexibility during tissue remodeling and early reproductive investment translates to natural conditions and affects fitness.
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Hayward, Adam D., Ilona Nenko, and Virpi Lummaa. "Early-life reproduction is associated with increased mortality risk but enhanced lifetime fitness in pre-industrial humans." Proceedings of the Royal Society B: Biological Sciences 282, no. 1804 (2015): 20143053. http://dx.doi.org/10.1098/rspb.2014.3053.
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The physiology of reproductive senescence in women is well understood, but the drivers of variation in senescence rates are less so. Evolutionary theory predicts that early-life investment in reproduction should be favoured by selection at the cost of reduced survival and faster reproductive senescence. We tested this hypothesis using data collected from preindustrial Finnish church records. Reproductive success increased up to age 25 and was relatively stable until a decline from age 41. Women with higher early-life fecundity (ELF; producing more children before age 25) subsequently had higher mortality risk, but high ELF was not associated with accelerated senescence in annual breeding success. However, women with higher ELF experienced faster senescence in offspring survival. Despite these apparent costs, ELF was under positive selection: individuals with higher ELF had higher lifetime reproductive success. These results are consistent with previous observations in both humans and wild vertebrates that more births and earlier onset of reproduction are associated with reduced survival, and with evolutionary theory predicting trade-offs between early reproduction and later-life survival. The results are particularly significant given recent increases in maternal ages in many societies and the potential consequences for offspring health and fitness.
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Melnikova, Ekaterina, Artem Kabanov, Sergey Nikitin, et al. "Application of Genomic Data for Reliability Improvement of Pig Breeding Value Estimates." Animals 11, no. 6 (2021): 1557. http://dx.doi.org/10.3390/ani11061557.
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Replacement pigs’ genomic prediction for reproduction (total number and born alive piglets in the first parity), meat, fatness and growth traits (muscle depth, days to 100 kg and backfat thickness over 6–7 rib) was tested using single-step genomic best linear unbiased prediction ssGBLUP methodology. These traits were selected as the most economically significant and different in terms of heritability. The heritability for meat, fatness and growth traits varied from 0.17 to 0.39 and for reproduction traits from 0.12 to 0.14. We confirm from our data that ssGBLUP is the most appropriate method of genomic evaluation. The validation of genomic predictions was performed by calculating the correlation between preliminary GEBV (based on pedigree and genomic data only) with high reliable conventional estimates (EBV) (based on pedigree, own phenotype and offspring records) of validating animals. Validation datasets include 151 and 110 individuals for reproduction, meat and fattening traits, respectively. The level of correlation (r) between EBV and GEBV scores varied from +0.44 to +0.55 for meat and fatness traits, and from +0.75 to +0.77 for reproduction traits. Average breeding value (EBV) of group selected on genomic evaluation basis exceeded the group selected on parental average estimates by 22, 24 and 66% for muscle depth, days to 100 kg and backfat thickness over 6–7 rib, respectively. Prediction based on SNP markers data and parental estimates showed a significant increase in the reliability of low heritable reproduction traits (about 40%), which is equivalent to including information about 10 additional descendants for sows and 20 additional descendants for boars in the evaluation dataset.