Segui questo link per vedere altri tipi di pubblicazioni sul tema: Reproductive.
Articoli di riviste sul tema "Reproductive"
Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili
Vedi i top-50 articoli di riviste per l'attività di ricerca sul tema "Reproductive".
Accanto a ogni fonte nell'elenco di riferimenti c'è un pulsante "Aggiungi alla bibliografia". Premilo e genereremo automaticamente la citazione bibliografica dell'opera scelta nello stile citazionale di cui hai bisogno: APA, MLA, Harvard, Chicago, Vancouver ecc.
Puoi anche scaricare il testo completo della pubblicazione scientifica nel formato .pdf e leggere online l'abstract (il sommario) dell'opera se è presente nei metadati.
Vedi gli articoli di riviste di molte aree scientifiche e compila una bibliografia corretta.
1
Kennedy, Anissa, Jacob Herman e Olav Rueppell. "Reproductive activation in honeybee ( Apis mellifera ) workers protects against abiotic and biotic stress". Philosophical Transactions of the Royal Society B: Biological Sciences 376, n. 1823 (8 marzo 2021): 20190737. http://dx.doi.org/10.1098/rstb.2019.0737.
Testo completoAbstract (sommario):
Social insect reproductives exhibit exceptional longevity instead of the classic trade-off between somatic maintenance and reproduction. Even normally sterile workers experience a significant increase in life expectancy when they assume a reproductive role. The mechanisms that enable the positive relation between the antagonistic demands of reproduction and somatic maintenance are unclear. To isolate the effect of reproductive activation, honeybee workers were induced to activate their ovaries. These reproductively activated workers were compared to controls for survival and gene expression patterns after exposure to Israeli Acute Paralysis Virus or the oxidative stressor paraquat. Reproductive activation increased survival, indicating better immunity and oxidative stress resistance. After qPCR analysis confirmed our experimental treatments at the physiological level, whole transcriptome analysis revealed that paraquat treatment significantly changed the expression of 1277 genes in the control workers but only two genes in reproductively activated workers, indicating that reproductive activation preemptively protects against oxidative stress. Significant overlap between genes that were upregulated by reproductive activation and in response to paraquat included prominent members of signalling pathways and anti-oxidants known to affect ageing. Thus, while our results confirm a central role of vitellogenin, they also point to other mechanisms to explain the molecular basis of the lack of a cost of reproduction and the exceptional longevity of social insect reproductives. Thus, socially induced reproductive activation preemptively protects honeybee workers against stressors, explaining their longevity. This article is part of the theme issue ‘Ageing and sociality: why, when and how does sociality change ageing patterns?'
2
Morton, Martin L., Maria E. Pereyra, John D. Crandall, Elizabeth A. MacDougall-Shackleton e Thomas P. Hahn. "Reproductive Effort and Return Rates in the Mountain White-Crowned Sparrow". Condor 106, n. 1 (1 febbraio 2004): 131–38. http://dx.doi.org/10.1093/condor/106.1.131.
Testo completoAbstract (sommario):
AbstractWe analyzed return rates of high-altitude-breeding Mountain White-crowned Sparrows (Zonotrichia leucophrys oriantha) in relation to five components of their previous season's reproductive effort: number of fledglings produced, double brooding, number of nesting attempts (first nests plus renests), total number of eggs laid, and fledging date. No relationship of return rate to reproductive effort occurred except in the case of fledging date. Fledging dates spanned a 2-month period from mid-June to mid-August. Returns of females to the study area held steady no matter when their chicks fledged in the previous breeding season, but male return rates increased significantly when their chicks fledged after 20 July. Coincident with that time frame, they entered molt and often withdrew parental care. We hypothesized that males in this montane environment, where thermoregulatory costs are high, traded off reproductive effort (parental care) with survival (return rates). This fits well with models of life-history evolution; however, the corresponding prediction that return rates of females with late-season broods should decrease due to their assumption of greater parental care was not supported. Apparently, the cost of reproduction shifted to the young: late-season nestlings grew more slowly, fledged at a smaller mass, and exhibited a fourfold increase in brood reductions. Their recruitment as breeders in the following season was also greatly reduced. Thus, a cost of reproduction was expressed in two forms, one as changes in survival rates of breeding males, the other as changes in quality of offspring.Esfuerzo Reproductivo y Tasas de Retorno en Zonotrichia leucophrys orianthaResumen. Analizamos las tasas de retorno en las poblaciones reproductivas de alta montaña de Zonotrichia leucophrys oriantha con relación a cinco componentes de su esfuerzo reproductivo de la estación anterior: número de volantones producidos, eventos de dobles nidadas, número de intentos de nidificación (primer nido más re-nidificaciones), número total de huevos puestos y fecha de emplumamiento. No encontramos una relación entre la tasa de retorno y el esfuerzo reproductivo, excepto en el caso de la fecha de emplumamiento. Las fechas de emplumamiento se extendieron por un período de dos meses, desde mediados de junio hasta mediados de agosto. El regreso de las hembras al área de estudio se mantuvo constante, sin importar cuándo los pichones abandonaron el nido en la estación reproductiva anterior, pero las tasas de retorno de los machos incrementaron significativamente cuando sus pichones dejaron el nido luego del 20 de julio. En coincidencia con este momento, los machos comenzaron la muda y frecuentemente dejaron de cuidar a de los pichones. Hipotetizamos que los machos en este ambiente de montaña, donde los costos de termorregulación son altos, canjearon esfuerzo reproductivo (cuidado parental) por supervivencia (tasas de retorno). Esto se ajusta adecuadamente con los modelos de evolución de historias de vida. Sin embargo, la predicción correspondiente de que las tasas de retorno de las hembras con nidadas tardías deberían disminuir debido a la suposición de que brindarían mayor cuidado parental, no fue respaldada. Aparentemente, el costo reproductivo sería trasladado a las crías: los pichones de finales de la estación crecieron más despacio, dejaron el nido con menor masa corporal y exhibieron un incremento de cuatro órdenes de magnitud en la reducción de la nidada. Su reclutamiento como individuos reproductivos en la siguiente estación también se redujo enormemente. De este modo, el costo reproductivo fue expresado de dos formas, una como cambios en las tasas de supervivencia de los machos reproductivos y la otra como cambios en la calidad de la progenie.
3
Washburn, Brian E., Douglas J. Tempel, Joshua J. Millspaugh, R. J. Gutiérrez e Mark E. Seamans. "Factors Related to Fecal Estrogens and Fecal Testosterone in California Spotted Owls". Condor 106, n. 3 (1 agosto 2004): 567–79. http://dx.doi.org/10.1093/condor/106.3.567.
Testo completoAbstract (sommario):
Abstract We estimated concentrations of fecal reproductive steroid metabolites in free-ranging California Spotted Owls (Strix occidentalis occidentalis) during the breeding season. We collected fresh fecal samples (n = 142) from 65 individual owls in the Sierra Nevada during April–August of 2001. We developed and validated radioimmunoassay procedures to quantify fecal estrogen metabolites and fecal testosterone metabolites. We used an information-theoretic approach to identify factors that might influence fecal estrogen (E), fecal testosterone (T), and fecal estrogen:testosterone ratio (E:T ratio) levels during the owl's breeding season. We hypothesized that factors related to sampling procedures, owl characteristics (sex, reproductive status), and habitat might influence fecal reproductive steroid levels. Our analyses suggested that sampling factors and owl characteristics, but not habitat variables, were related to fecal reproductive steroid levels in Spotted Owls. Our most supported models explained <30% of the observed variation. Fecal testosterone levels were higher in male Spotted Owls than females, whereas E:T ratios were higher in females compared to males. High fecal estrogens were correlated with high fecal glucocorticoids in nonbreeding Spotted Owls, whereas fecal estrogens and fecal glucocorticoids were not related in breeding birds. Sampling influenced fecal reproductive steroid measures, and bias from small-mass fecal samples might partially explain these relationships. Noninvasive measurements of fecal reproductive steroids might be useful for sex determination and reproductive assessment of free-ranging Spotted Owls. However, more research is needed to understand the variability we observed in sex steroids before this technique can be effective in conservation studies. Factores Asociados con los Estrógenos Fecales y la Testosterona Fecal en Strix occidentalis occidentalis Resumen. Estimamos las concentraciones de metabolitos esteroides reproductivos en individuos silvestres de la especie Strix occidentalis occidentalis durante la época reproductiva. Colectamos muestras fecales frescas (n = 142) pertenecientes a 65 lechuzas en la Sierra Nevada entre abril y agosto de 2001. Desarrollamos y validamos un procedimiento de radioinmunoensayo para cuantificar metabolitos de estrógeno fecales y metabolitos de testosterona fecales. Utilizamos un enfoque informativo-teórico para identificar los factores que podrían influenciar los niveles de estrógenos fecales (E), testosterona fecal (T) y el cociente entre estrógenos y testosterona (cociente E:T) durante la época reproductiva de las lechuzas. Hipotetizamos que factores relacionados con los procedimientos de muestreo, características de la lechuza (sexo, estado reproductivo) y el hábitat podrían influenciar los niveles de esteroides reproductivos en las fecas. Nuestros análisis sugieren que los factores asociados al muestreo y las características de la lechuza se correlacionaron con los niveles de esteroides reproductivos en las fecas, pero éstos no se relacionaron con las variables de hábitat. Nuestro modelo más robusto explicó <30% de la variación observada. Los niveles de testosterona fecal fueron mayores en los machos que en las hembras, mientras que el cuociente E:T fue mayor en las hembras que en los machos. En lechuzas no reproductivas, los niveles altos de estrógenos fecales se correlacionaron con niveles altos de glucocorticoides fecales, mientras que en individuos reproductivos los estrógenos fecales y los glucorticoides fecales no se correlacionaron. Estas relaciones pueden ser explicadas en parte por la influencia del muestreo sobre las medidas de esteroides reproductivos fecales y por el sesgo causado por muestras fecales muy livianas. Los niveles de esteroides reproductivos fecales medidos con técnicas no invasivas pueden ser útiles para la determinación de sexos y la evaluación del estado reproductivo de individuos silvestres de la especie S. occidentalis occidentalis. Sin embargo, antes de que esta técnica pueda ser efectiva en estudios de conservación, se requiere de más investigación para entender la variabilidad que observamos en los niveles de esteroides sexuales.
4
Bollmann, Kurt, e Heinz-Ulrich Reyer. "Reproductive Success of Water Pipits in an Alpine Environment". Condor 103, n. 3 (1 agosto 2001): 510–20. http://dx.doi.org/10.1093/condor/103.3.510.
Testo completoAbstract (sommario):
Abstract To understand the evolution of avian reproductive strategies it is important to assess how differences in reproductive success are related to timing of the breeding season, quality of nesting territories or breeders, or to a combination of these factors. Over three years, we studied the reproductive performance of female Water Pipits (Anthus spinoletta) in a temporally and spatially variable alpine environment. The study area covered two valley slopes that differed in the probability of nest predation, food availability, and climate. Nest predation and harsh weather were the main proximate causes of differences in female reproductive success. Because these two environmental factors were locally unpredictable, individual females could best optimize their seasonal reproductive success by choosing the “right” breeding time. The average number of young fledged per season was inversely related to the date of initial breeding and increased from females with only first attempts, through females with replacement clutches, to females that raised two broods. Hence, the main advantage of early breeding lies in the chance of rearing a second brood after the first has fledged, or of producing a replacement clutch if the first fails due to predation or harsh weather. Éxito Reproductivo de Anthus spinoletta en un Ambiente Alpino Resumen. Para entender la evolución de las estrategias reproductivas de las aves es importante determinar cómo las diferencias en el éxito reproductivo se relacionan con el comienzo de la época reproductiva, la calidad de los territorios de nidificación o los reproductores o con una combinación de estos factores. Durante un período de tres años, estudiamos el desempeño reproductivo de hembras de Anthus spinoletta en un ambiente alpino temporal y espacialmente variable. El sitio de estudio comprendió dos laderas que diferían en la probabilidad de depredación de nidos, disponibilidad de alimento y clima. La depredación de nidos y el clima severo fueron las principales causas proximales de la diferencia del éxito reproductivo de las hembras. Debido a que ambos factores ambientales fueron localmente inpredecibles, cada individuo hembra podía optimizar el éxito de su período reproductivo eligiendo el tiempo “correcto” para reproducirse en la temporada. El número promedio de juveniles por temporada se relacionó inversamente con la fecha del inicio de la reproducción y aumentó desde hembras con sólo un intento de cría, pasando por hembras que reemplazaron sus nidadas, hasta hembras que criaron dos nidadas. Por tanto, la ventaja principal de reproducirse tempranamente en la temporada está dada por la posibilidad de criar una segunda nidada luego de la partida de los primeros juveniles o de producir una nueva nidada si la primera falla debido a depredación o clima severo.
5
Rotella, Jay J., Robert G. Clark e Alan D. Afton. "Survival of Female Lesser Scaup: Effects of Body Size, Age, and Reproductive Effort". Condor 105, n. 2 (1 maggio 2003): 336–47. http://dx.doi.org/10.1093/condor/105.2.336.
Testo completoAbstract (sommario):
AbstractIn birds, larger females generally have greater breeding propensity, reproductive investment, and success than do smaller females. However, optimal female body size also depends on how natural selection acts during other parts of the life cycle. Larger female Lesser Scaup (Aythya affinis) produce larger eggs than do smaller females, and ducklings from larger eggs survive better than those hatching from smaller eggs. Accordingly, we examined patterns of apparent annual survival for female scaup and tested whether natural selection on female body size primarily was stabilizing, a frequent assumption in studies of sexually dimorphic species in which males are the larger sex, or was directional, counteracting reproductive advantages of large size. We estimated survival using mark-recapture methods for individually marked females from two study sites in Canada (Erickson, Manitoba; St. Denis, Saskatchewan). Structurally larger (adults) and heavier (ducklings) females had lower survival than did smaller individuals in Manitoba; no relationship was detected in adults from Saskatchewan. Survival of adult females declined with indices of increasing reproductive effort at both sites; consequently, the cost of reproduction could explain age-related patterns of breeding propensity in scaup. Furthermore, if larger females are more likely to breed than are smaller females, then cost of reproduction also may help explain why survival was lower for larger females. Overall, we found that advantages of large body size of female scaup during breeding or as young ducklings apparently were counteracted by natural selection favoring lightweight juveniles and structurally smaller adult females through higher annual survival.Sobrevivencia de Aythya affinis: Efectos del Tamaño Corporal, Edad y Esfuerzo ReproductivoResumen. En las aves, las hembras de mayor tamaño generalmente presentan una mayor predisposición a la reproducción, mayor inversión reproductiva y mayor éxito que las hembras de menor tamaño. Sin embargo, el tamaño óptimo de la hembra también depende de cómo la selección natural opera durante otras etapas del ciclo de vida. Hembras de Aythya affinis más grandes producen huevos de mayor tamaño que hembras más pequeñas, y los polluelos provenientes de huevos más grandes sobreviven mejor que aquellos que eclosionan de huevos más pequeños. Consiguientemente, examinamos los patrones de sobrevivencia anual aparente para hembras de A. affinis y probamos si la selección natural sobre el tamaño del cuerpo de las hembras era principalmente estabilizadora (una suposición frecuente en estudios de especies sexualmente dimórficas en que los machos son el sexo mayor), o era direccional, contrarrestando las ventajas reproductivas de un tamaño mayor. Estimamos la sobrevivencia de hembras utilizando métodos de marcaje y recaptura en dos sitios de estudio (Erickson, Manitoba; St. Denis, Saskatchewan). Hembras estructuralmente más grandes (adultas) y más pesadas (polluelos) tuvieron una menor sobrevivencia que individuos más pequeños en Manitoba; no se detectó una relación entre adultos de Saskatchewan. En ambos sitios la sobrevivencia de hembras adultas decreció con los índices de incremento de esfuerzo reproductivo; consecuentemente el costo reproductivo podría explicar los patrones de predisposición reproductiva relacionados a la edad en A. affinis. Además, si las hembras de mayor tamaño presentan mayor probabilidad de reproducirse que las hembras pequeñas, entonces el costo reproductivo también podría ayudar a explicar porqué la sobrevivencia fue menor para hembras más grandes. En general encontramos que en las hembras de A. affinis las ventajas de un tamaño corporal grande durante la cría o como juveniles fueron aparentemente contrarestadas por la selección natural que favorece juveniles de peso liviano y hembras adultas estructuralmente más pequeñas a través de una mayor sobrevivencia anual.
6
Sun, Qian, Jordan D. Hampton, Austin Merchant, Kenneth F. Haynes e Xuguo Zhou. "Cooperative policing behaviour regulates reproductive division of labour in a termite". Proceedings of the Royal Society B: Biological Sciences 287, n. 1928 (10 giugno 2020): 20200780. http://dx.doi.org/10.1098/rspb.2020.0780.
Testo completoAbstract (sommario):
Reproductive conflicts are common in insect societies where helping castes retain reproductive potential. One of the mechanisms regulating these conflicts is policing, a coercive behaviour that reduces direct reproduction by other individuals. In eusocial Hymenoptera (ants, bees and wasps), workers or the queen act aggressively towards fertile workers, or destroy their eggs. In many termite species (order Blattodea), upon the death of the primary queen and king, workers and nymphs can differentiate into neotenic reproductives and inherit the breeding position. During this process, competition among neotenics is inevitable, but how this conflict is resolved remains unclear. Here, we report a policing behaviour that regulates reproductive division of labour in the eastern subterranean termite, Reticulitermes flavipes . Our results demonstrate that the policing behaviour is a cooperative effort performed sequentially by successful neotenics and workers. A neotenic reproductive initiates the attack of the fellow neotenic by biting and displays alarm behaviour. Workers are then recruited to cannibalize the injured neotenic. Furthermore, the initiation of policing is age-dependent, with older reproductives attacking younger ones, thereby inheriting the reproductive position. This study provides empirical evidence of policing behaviour in termites, which represents a convergent trait shared between eusocial Hymenoptera and Blattodea.
7
Gandini, Patricia, Esteban Frere e P. Dee Boersma. "Status and conservation of Magellanic PenguinsSpheniscus magellanicusin Patagonia, Argentina". Bird Conservation International 6, n. 4 (dicembre 1996): 307–16. http://dx.doi.org/10.1017/s0959270900001787.
Testo completoAbstract (sommario):
SummaryThere are 36 breeding colonies of Magellanic PenguinsSpheniscus magellanicusalong the coast of mainland Argentina. During the breeding period we counted the number of active nests and estimated the breeding population was approximately 652,000 pairs. Development of coastal areas is diminishing the quality of Magellanic Penguin breeding habitat and reducing penguin reproductive success. Adult mortality rates are increasing because of human activities. Maritime petroleum traffic and petroleum operations are known to cause mortality. Fishing activities cause incidental mortality and may negatively affect penguin foraging and reproductive success. In some areas, offal is increasing gull populations with a corresponding increase in predation on penguin eggs and chicks, thereby lowering reproductive success. These sources of mortality are relatively recent and are human caused. We found three areas where human activities are of particular concern: Península Valdés, Golfo San Jorge and Estrecho de Magallanes. Human impacts on Magellanic Penguin populations could be reduced, benefiting the tourist industry where yearly tens of thousands of people come to the provinces of Chubut and Santa Cruz to visit penguin colonies.Existen 36 colonias de pingüino de MagallanesSpheniscus magellanicusa lo largo de la costa Argentina. La población reproductiva se estimó en 652,000 parejas realizando un conteo de nidos activos durante la estación reproductiva. El desarrollo de las áreas costeras está reduciendo la calidad del hábitat de reproducción y el éxito reproductivo del pingüino de Magallanes. El tráfico de petróleo y las actividades relacionadas son conocidas causas de mortalidad. Las actividades pesqueras están causando mortalidad incidental y pueden estar afectando negativamente el éxito de alimentatión y reproductivo. En algunas áreas la basura está contribuyendo al aumento de la población de gaviotas, incrementándose la predación sobre huevos y pichones de pingüino reduciendo su éxito reproductivo. Estas fuentes de mortalidad son relativamente recientes y provocadas por el hombre. Hemos detectado tres áreas donde la mortalidad relacionada con actividades humanas es preocupante: Península Valdés, Golfo San Jorge y Estrecho de Magallanes. El impacto humano sobre la población de pingüino de Magallanes podría reducirse y beneficiar la industria turística de las provincias de Chubut y Santa Cruz, donde anualmente decenas de miles de personas visitan las colonias reproductivas del pingüino.
8
Porneluzi, Paul A. "Prior Breeding Success Affects Return Rates of Territorial Male Ovenbirds". Condor 105, n. 1 (1 febbraio 2003): 73–79. http://dx.doi.org/10.1093/condor/105.1.73.
Testo completoAbstract (sommario):
AbstractI examined the hypothesis that male Ovenbirds (Seiurus aurocapillus) make breeding dispersal decisions based on prior breeding experience at a site. I determined the reproductive success of color-banded male Ovenbirds at sites in fragmented and unfragmented landscapes in Missouri from 1992–1995. I documented which individuals returned and I recorded their reproductive success upon return as well as the success of birds new to each plot. I obtained similar results in both landscapes. Males with different histories of reproductive success returned at different rates. Only 2 of 22 males that were paired but failed to raise young returned in the following year, whereas the return rates of unpaired males (41%, n = 37) and males that successfully raised young (54%, n = 57) did not differ significantly (P = 0.19). The patterns were more consistent with the hypothesis that return rates were due to decisions about dispersal rather than difference in survival of individuals in these groups.El Éxito Reproductivo Previo Afecta Índices de Regreso de Machos Territoriales de Seiurus aurocapillusResumen. Examiné la hipótesis de que individuos de Seiurus aurocapillus hacen decisiones de dispersión reproductiva basadas en las experiencias reproductivas previas en un sitio. Determiné el éxito reproductivo de machos con anillos de color en lugares en terrenos fragmentados y no fragmentados de Missouri entre 1992 y 1995. Documenté cuáles individuos regresaron y su éxito reproductivo al regresar, y también el éxito de pájaros nuevos en cada sitio. Obtuve resultados semejantes en ambos paisajes. Los machos con historias de éxito reproductivo diferentes presentaron índices de regreso diferentes. Solamente 2 de 22 machos apareados que no produjeron cría volvieron al año siguiente, mientras que los índices de regreso de machos no apareados (41%, n = 37) y de los machos que produjeron crías exitosamente (54%, n = 57) no difirieron significativamente (P = 0.19). Los patrones concuerdan más con la hipótesis de que los índices de regreso se deberieron a las decisiones de dispersión y no a la diferencia de supervivencia de individuos en estos grupos.
9
Chandra, Vikram, Ingrid Fetter-Pruneda, Peter R. Oxley, Amelia L. Ritger, Sean K. McKenzie, Romain Libbrecht e Daniel J. C. Kronauer. "Social regulation of insulin signaling and the evolution of eusociality in ants". Science 361, n. 6400 (26 luglio 2018): 398–402. http://dx.doi.org/10.1126/science.aar5723.
Testo completoAbstract (sommario):
Queens and workers of eusocial Hymenoptera are considered homologous to the reproductive and brood care phases of an ancestral subsocial life cycle. However, the molecular mechanisms underlying the evolution of reproductive division of labor remain obscure. Using a brain transcriptomics screen, we identified a single gene,insulin-like peptide 2(ilp2), which is always up-regulated in ant reproductives, likely because they are better nourished than their nonreproductive nestmates. In clonal raider ants (Ooceraea biroi), larval signals inhibit adult reproduction by suppressingilp2, thus producing a colony reproductive cycle reminiscent of ancestral subsociality. However, increasing ILP2 peptide levels overrides larval suppression, thereby breaking the colony cycle and inducing a stable division of labor. These findings suggest a simple model for the origin of ant eusociality via nutritionally determined reproductive asymmetries potentially amplified by larval signals.
10
Rubenstein, Dustin R., Carlos A. Botero e Eileen A. Lacey. "Discrete but variable structure of animal societies leads to the false perception of a social continuum". Royal Society Open Science 3, n. 5 (maggio 2016): 160147. http://dx.doi.org/10.1098/rsos.160147.
Testo completoAbstract (sommario):
Animal societies are typically divided into those in which reproduction within a group is monopolized by a single female versus those in which it is shared among multiple females. It remains controversial, however, whether these two forms of social structure represent distinct evolutionary outcomes or endpoints along a continuum of reproductive options. To address this issue and to determine whether vertebrates and insects exhibit the same patterns of variation in social structure, we examined the demographic and reproductive structures of 293 species of wasps, ants, birds and mammals. Using phylogenetically informed comparative analyses, we found strong evidence indicating that not all reproductive arrangements within social groups are viable in nature and that in societies with multiple reproductives, selection favours instead taxon-specific patterns of decrease in the proportion of breeders as a function of group size. These outcomes suggest that the selective routes to sociality differ depending upon whether monopolization of reproduction by one individual is possible and that variation within and among taxonomic groups may lead to the false perception of a continuum of social structures. Thus, the occurrence of very large societies may require either complete reproductive monopolization (monogyny/singular breeding) or the maintenance of a taxon-specific range of values for the proportional decrease in the number of breeders within a group (polygyny/plural breeding), both of which may reduce reproductive conflict among females.
11
Webster, M. M., e K. N. Laland. "Reproductive state affects reliance on public information in sticklebacks". Proceedings of the Royal Society B: Biological Sciences 278, n. 1705 (8 settembre 2010): 619–27. http://dx.doi.org/10.1098/rspb.2010.1562.
Testo completoAbstract (sommario):
The degree to which animals use public and private sources of information has important implications for research in both evolutionary ecology and cultural evolution. While researchers are increasingly interested in the factors that lead individuals to vary in the manner in which they use different sources of information, to date little is known about how an animal's reproductive state might affect its reliance on social learning. Here, we provide experimental evidence that in foraging ninespine sticklebacks ( Pungitius pungitius ), gravid females increase their reliance on public information generated by feeding demonstrators in choosing the richer of two prey patches than non-reproductive fish, while, in contrast, reproductive males stop using public information. Subsequent experiments revealed reproductive males to be more efficient asocial foragers, less risk-averse and generally less social than both reproductive females and non-reproductives. These findings are suggestive of adaptive switches in reliance on social and asocial sources of information with reproductive condition, and we discuss the differing costs of reproduction and the proximate mechanisms that may underlie these differences in information use. Our findings have important implications for our understanding of adaptive foraging strategies in animals and for understanding the way information diffuses through populations.
12
Hasegawa, Shigeaki, e Hiroshi Takeda. "Functional specialization of current shoots as a reproductive strategy in Japanese alder (Alnus hirsuta var. sibirica)". Canadian Journal of Botany 79, n. 1 (1 gennaio 2001): 38–48. http://dx.doi.org/10.1139/b00-143.
Testo completoAbstract (sommario):
Current shoots, which form the crown of a tree, are specialized in various functions such as crown expansion, reproduction, and assimilation. We examined the temporal and spatial distribution of reproductive shoots in Alnus hirsuta Turcz. var. sibirica (Fischer) C.K. Schn., assessed their direct and indirect costs of reproduction, and explained their distribution in the crown as the reproductive strategy of a current shoot population. The upper and lower limits to the lengths of current shoots for reproductive growth (flower formation) were 40 and 10 cm, respectively. Reproductive 1-year-old shoots produced fewer shoots in the following year than non-reproductive 1-year-old shoots. In current shoots longer than 40 cm, the increment of reproductive output in the following year by abandonment of reproduction surpassed the decrement of reproductive output in the current year by abandonment of reproduction. This may be one reason for the upper limit of reproductive shoot length. Thus, the current shoot population of A. hirsuta var. sibirica may be divided into three functionally specialized subpopulations: reproductive, maintenance, and exploratory. This specialization is considered to be a reproductive strategy to maximize their lifetime reproductive success.Key words: current shoot population, reproductive ecology, functional specialization, cost of reproduction, Japanese alder.
13
Kustan, Jacqueline M., Karen P. Maruska e Russell D. Fernald. "Subordinate male cichlids retain reproductive competence during social suppression". Proceedings of the Royal Society B: Biological Sciences 279, n. 1728 (6 luglio 2011): 434–43. http://dx.doi.org/10.1098/rspb.2011.0997.
Testo completoAbstract (sommario):
Subordinate males, which are excluded from reproduction often save energy by reducing their investment in sperm production. However, if their position in a dominance hierarchy changes suddenly they should also rapidly attain fertilization capability. Here, we asked how social suppression and ascension to dominance influences sperm quality, spermatogenesis and reproductive competence in the cichlid Astatotilapia burtoni , where reproduction is tightly coupled to social status. Dominant territorial (T) males are reproductively active while subordinate non-territorial (NT) males are suppressed, but given the opportunity, NT males will perform dominance behaviours within minutes and attain T male testes size within days. Using the thymidine analogue 5-bromo-2-deoxyuridine (BrdU) to label germ cell proliferation, we found that the spermatogenic cycle takes approximately 11–12 days, and social status had no effect on proliferation, suggesting that spermatogenesis continues during reproductive suppression. Although sperm velocity did not differ among social states, NT males had reduced sperm motility. Remarkably, males ascending in status showed sperm motility equivalent to T males within 24 h. Males also successfully reproduced within hours of social opportunity, despite four to five weeks of suppression and reduced testis size. Our data suggest that NT males maintain reproductive potential during suppression possibly as a strategy to rapidly improve reproductive fitness upon social opportunity.
14
Chak, Solomon Tin Chi, J. Emmett Duffy e Dustin R. Rubenstein. "Reproductive skew drives patterns of sexual dimorphism in sponge-dwelling snapping shrimps". Proceedings of the Royal Society B: Biological Sciences 282, n. 1809 (22 giugno 2015): 20150342. http://dx.doi.org/10.1098/rspb.2015.0342.
Testo completoAbstract (sommario):
Sexual dimorphism is typically a result of strong sexual selection on male traits used in male–male competition and subsequent female choice. However, in social species where reproduction is monopolized by one or a few individuals in a group, selection on secondary sexual characteristics may be strong in both sexes. Indeed, sexual dimorphism is reduced in many cooperatively breeding vertebrates and eusocial insects with totipotent workers, presumably because of increased selection on female traits. Here, we examined the relationship between sexual dimorphism and sociality in eight species of Synalpheus snapping shrimps that vary in social structure and degree of reproductive skew. In species where reproduction was shared more equitably, most members of both sexes were physiologically capable of breeding. However, in species where reproduction was monopolized by a single individual, a large proportion of females—but not males—were reproductively inactive, suggesting stronger reproductive suppression and conflict among females. Moreover, as skew increased across species, proportional size of the major chela—the primary antagonistic weapon in snapping shrimps—increased among females and sexual dimorphism in major chela size declined. Thus, as reproductive skew increases among Synalpheus , female–female competition over reproduction appears to increase, resulting in decreased sexual dimorphism in weapon size.
15
Tsuchida, Koji, Takaharu Saigo, Kazuyuki Asai, Tomoko Okamoto, Masaki Ando, Tetsu Ando, Ken Sasaki et al. "Reproductive workers insufficiently signal their reproductive ability in a paper wasp". Behavioral Ecology 31, n. 2 (22 gennaio 2020): 577–90. http://dx.doi.org/10.1093/beheco/arz212.
Testo completoAbstract (sommario):
Abstract Why workers forfeit direct reproduction is a crucial question in eusocial evolution. Worker reproduction provides an excellent opportunity to understand the mechanism of kin conflict resolution between the queen and workers. We evaluated behavioral and physiological differences among females in the paper wasp Polistes chinensis antennalis to examine why some workers reproduce under queenright conditions. Reproductive workers were old and foraged less early in the season; their cuticular hydrocarbon (CHC) profiles overlapped with those of queens but were significantly different. The distinct CHC profile of the eggs of the queen likely represented a cue for policing against those by workers. Juvenile hormone (JH) and dopamine seemed to be associated with gonadotropic function, and the JH level of reproductive workers was similar to that of the queen. The high JH level of reproductive workers likely facilitated their reproduction even under queenright conditions. Gene expression levels of the queen and reproductive workers differed only in vitellogenin. These results suggest that worker reproduction is facilitated by an increase in JH level; however, CHC is not a fertility-linked signal, but a queen-linked signal; consequently, reproductive workers without a queen-linked signal might be allowed to stay within the colony.
16
Sheller, Mimi. "The reproduction of reproduction: theorizing reproductive (im)mobilities". Mobilities 15, n. 2 (25 febbraio 2020): 188–95. http://dx.doi.org/10.1080/17450101.2020.1730608.
Testo completo
17
Belk, Mark C., Peter J. Meyers e J. Curtis Creighton. "Bigger Is Better, Sometimes: The Interaction between Body Size and Carcass Size Determines Fitness, Reproductive Strategies, and Senescence in Two Species of Burying Beetles". Diversity 13, n. 12 (11 dicembre 2021): 662. http://dx.doi.org/10.3390/d13120662.
Testo completoAbstract (sommario):
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.
18
ANDREOU, D., M. HUSSEY, S. W. GRIFFITHS e R. E. GOZLAN. "Influence of host reproductive state onSphaerothecum destruensprevalence and infection level". Parasitology 138, n. 1 (21 luglio 2010): 26–34. http://dx.doi.org/10.1017/s0031182010000983.
Testo completoAbstract (sommario):
SUMMARYSphaerothecum destruensis an obligate intracellular parasite with the potential to cause high mortalities and spawning inhibition in the endangered cyprinidLeucaspius delineatus. We investigated the influence ofL. delineatus’s reproductive state on the prevalence and infection level ofS. destruens. A novel real time quantitative polymerarse chain reaction (qPCR) was developed to determineS. destruens’ prevalence and infection level. These parameters were quantified and compared in reproductive and non-reproductiveL. delineatus. The detection limit of theS. destruensspecific qPCR was determined to be 1 pg of purifiedS. destruensgenomic DNA. Following cohabitation in the lab, reproductiveL. delineatushad a significantly higherS. destruensprevalence (P<0·05) and infection levels (P<0·01) compared to non-reproductiveL. delineatus. S. destruensprevalence was 19% (n=40) in non-reproductiveL. delineatusand 41% (n=32) in reproductiveL. delineatus. However, there was no difference inS. destruensprevalence in reproductive and non-reproductive fish under field conditions. Mean infection levels were 18 and 99 pgS. destruensDNA per 250 ngL. delineatusDNA for non-reproductive and reproductiveL. delineatusrespectively. The present work indicates thatS. destruensinfection inL. delineatuscan be influenced by the latter's reproductive state and provides further support for the potential adverse impact ofS. destruenson the conservation ofL. delineatuspopulations.
19
Masuoka, Yudai, Keigo Nuibe, Naoto Hayase, Takateru Oka e Kiyoto Maekawa. "Reproductive Soldier Development Is Controlled by Direct Physical Interactions with Reproductive and Soldier Termites". Insects 12, n. 1 (15 gennaio 2021): 76. http://dx.doi.org/10.3390/insects12010076.
Testo completoAbstract (sommario):
In eusocial insects (e.g., ants, bees, and termites), the roles of different castes are assigned to different individuals. These castes possess unique phenotypes that are specialized for specific tasks. The acquisition of sterile individuals with specific roles is considered a requirement for social evolution. In termites, the soldier is a sterile caste. In primitive taxa (family Archotermopsidae and Stolotermitidae), however, secondary reproductives (neotenic reproductives) with their mandibles developed into weapons (so-called reproductive soldiers, also termed as soldier-headed reproductives or soldier neotenics) have been reported. To understand the developmental mechanism of this unique caste, it is necessary to understand the environmental cues and developmental processes of reproductive soldiers under natural conditions. Here, we established efficient conditions to induce reproductive soldiers in Zootermopsis nevadensis. Male reproductive soldiers frequently developed after the removal of both the king and soldiers from an incipient colony. Similarly, high differentiation rates of male reproductive soldiers were observed after king-and-soldier separation treatment using wire mesh. However, no male reproductive soldiers were produced without direct interaction with the queen. These results suggest that male reproductive soldier development is repressed by direct physical interactions with both the king and soldiers and facilitated by direct physical interaction with the queen.
20
Frohlick, Sue, Kristin Lozanski, Amy Speier e Mimi Sheller. "Mobilities Meet Reproductive Vibes . . ." Transfers 9, n. 1 (1 giugno 2019): 95–102. http://dx.doi.org/10.3167/trans.2019.090108.
Testo completoAbstract (sommario):
What mobilizes people to take up reproductive options, directions, and trajectories in ways that generate the possibilities and practices of mobilities? People’s desires for procreation or to resolve fertility challenges or partake in sperm donation, egg freezing, or surrogacy; the need for abortion services; and forced evacuation for childbirth care all involve movement. Reproductive aspirations, norms, and regulations move people’s bodies, as well as related technologies and bioproducts. At the same time, these corporeal, material, in/tangible mobilities of bodies, things, and ideas are also generative of reproductive imaginaries and practices. Reproduction is mobile and movement affects reproduction. Building from an interdisciplinary workshop on reproductive mobilities in Kelowna, Canada, this article aims to push the mobilities framework toward the edges of feminist, affect, queer, decolonizing, materialist, and nonrepresentational theories in thinking through both reproduction and movement.
21
Clark, Nathaniel L., Jan E. Aagaard e Willie J. Swanson. "Evolution of reproductive proteins from animals and plants". Reproduction 131, n. 1 (gennaio 2006): 11–22. http://dx.doi.org/10.1530/rep.1.00357.
Testo completoAbstract (sommario):
Sexual reproduction is a fundamental biological process common among eukaryotes. Because of the significance of reproductive proteins to fitness, the diversity and rapid divergence of proteins acting at many stages of reproduction is surprising and suggests a role of adaptive diversification in reproductive protein evolution. Here we review the evolution of reproductive proteins acting at different stages of reproduction among animals and plants, emphasizing common patterns. Although we are just beginning to understand these patterns, by making comparisons among stages of reproduction for diverse organisms we can begin to understand the selective forces driving reproductive protein diversity and the functional consequences of reproductive protein evolution.
22
Persson, Jens. "Female wolverine (Gulo gulo) reproduction: reproductive costs and winter food availability". Canadian Journal of Zoology 83, n. 11 (1 novembre 2005): 1453–59. http://dx.doi.org/10.1139/z05-143.
Testo completoAbstract (sommario):
An individual has only a given amount of resources, and therefore an increase in one demographic trait results in a trade-off that necessitates a decrease in a different demographic trait. In general, the main factor determining an individual mammal's reproductive investment is food supply. This study addresses how female wolverine (Gulo gulo (L., 1758)) reproduction is limited. I tested two complementary hypotheses: (1) current reproduction is affected by the costs of reproduction in the preceding year and (2) current reproduction is affected by food availability in the current winter. I addressed the first hypothesis by comparing reproductive rates of females in relation to their reproductive effort in the preceding year. I experimentally tested the second hypothesis by comparing reproductive rates of food-supplemented females versus non-supplemented females. Reproduction incurred costs on female wolverines that affected future reproduction, and reproductive costs appeared to be related to the duration of parental care. Reproduction was higher for food-supplemented females than for non-supplemented females, even though all food-supplemented females had reproduced the preceding year. This study suggests that reproduction is limited by winter food availability and that additional food can compensate for reproductive costs. Thus, I suggest that female wolverine reproduction is determined by their condition in winter, which is a result of the combined effect of reproductive costs and winter food availability.
23
Ho, J. D., N. A. Moltschaniwskyj e C. G. Carter. "The effect of variability in growth on somatic condition and reproductive status in the southern calamary Sepioteuthis australis". Marine and Freshwater Research 55, n. 4 (2004): 423. http://dx.doi.org/10.1071/mf03149.
Testo completoAbstract (sommario):
The aim of the present study was to determine how the lifetime growth rates of adult southern calamary Sepioteuthis australis related to somatic and reproductive condition. A hierarchy of biological levels was explored: whole-animal, muscle fibre, and proximal condition. Evidence at all biological levels suggested that allocation of energy given to growth and reproduction was gender-specific. Females may not be allocating the same level of energy to somatic growth due to a greater requirement to re-allocate energy for reproductive growth. There was evidence that faster-growing males were in better somatic and reproductive condition. However, both males and females in better somatic condition were also in better reproductive condition. Fast growth rates by individuals were achieved primarily by muscle fibre growth, rather than production of new fibres. However, mantle muscle instantaneous growth rates (assessed through RNA : protein ratio) decreased as males became larger and more reproductively mature; no association was evident in females. An inverse correlation between gonad size and muscle instantaneous growth rates in females suggested energy was being directed away from somatic growth and towards reproductive growth. There was evidence that lifetime growth rates could predict the reproductive or somatic condition of adult calamary, but this was gender-specific.
24
Holekamp, Kay E., e Scott Nunes. "Seasonal variation in body weight, fat, and behavior of California ground squirrels (Spermophilus beecheyi)". Canadian Journal of Zoology 67, n. 6 (1 giugno 1989): 1425–33. http://dx.doi.org/10.1139/z89-202.
Testo completoAbstract (sommario):
Annual cycles of activity and reproduction were documented in a population of California ground squirrels (Spermophilus beecheyi) in coastal California. Behavior, body mass, and reproduction were monitored in marked individuals between November 1983 and January 1986 through regular focal animal observation and livetrapping. Mass measures for reproductive tracts and gonadal fat pads were concurrently collected from a separate population of animals sacrificed in the laboratory. Mass and feeding behavior varied with sex and age. Surface activity, body weight, fat pad mass, and food consumption appeared to be closely related in this population. Fat pad mass was greater in nonreproductive than in reproductively active members of both sexes, as was body mass among males. Female body mass was greatest during pregnancy. Comparisons among reproductive status groups within each sex revealed significant differences in feeding, resting, vigilance, locomotor activity, and social behavior. Comparison with other populations suggested that S. beecheyi is highly variable with respect to demography, seasonal activity, timing of reproduction, and social behavior.
25
Chateauneuf, Doris. "Projet familial, infertilité et désir d’enfant : usages et expériences de la procréation médicalement assistée en contexte québécois". Enfances, Familles, Générations, n. 15 (2 marzo 2012): 61–77. http://dx.doi.org/10.7202/1008146ar.
Testo completoAbstract (sommario):
Les couples qui rencontrent des problèmes d’infertilité et qui cherchent une solution pour leur désir d’enfant se tournent pour la plupart vers la médecine reproductive, celle-ci faisant office d’autorité quant aux questions relatives à la grossesse et à la reproduction. La valorisation de l’enfant, tant sur le plan social qu’au sein de la conjugalité, intervient dans le vécu relatif à l’infertilité et influence le regard que posent les couples sur les nouvelles technologies reproductives. À ce titre, l’étude des relations entre les médecins et les couples infertiles met en évidence les différents discours qui circulent sur la reproduction et fait aussi état des débats et enjeux liés au développement des techniques reproductives et à leur accès grandissant.
26
Vicentin, Maria Cristina Gonçalves, e Daniel Adolpho Dantin Assis. "Niñas en el sistema de justicia brasileño: El necesario debate sobre los derechos sexuales y reproductivos (Girls in the Brazilian Justice System: The Necessary Debate on Sexual and Reproductive Rights)". Oñati Socio-legal Series 10, n. 2 (1 aprile 2020): 388–414. http://dx.doi.org/10.35295/osls.iisl/0000-0000-0000-1072.
Testo completoAbstract (sommario):
En este artículo presentamos el debate brasileño sobre los derechos sexuales y reproductivos en su condición de derechos políticos que pueden favorecer avances significativos en la concepción y ampliación de los derechos de niñas, niños y adolescentes principalmente referidos al concepto de autonomía. A través de la revisión de los marcos legales y de la literatura, específicamente relacionados a las niñas en el sistema de justicia brasileño, evidenciamos tensiones entre el ejercicio de los derechos sexuales y reproductivos y las respectivas prácticas institucionales. Consideramos que es fundamental una perspectiva de protección que asegure las condiciones de integridad de sus cuerpos, pero que garantice simultáneamente el usufructo de los derechos relativos a la sexualidad. La articulación de derechos sexuales y reproductivos y la salud sexual y reproductiva puede ser un camino prometedor, especialmente para las adolescentes que encuentran mayores obstáculos para su ejercicio. In this article, we present the Brazilian debate on sexual and reproductive rights as political rights, which could bring significant advances in creating and broadening the rights of children and adolescents. By means of a revision of legal milestones and of the literature, more specifically that which relates to girls in the Brazilian justice system, we highlight tensions between sexual and reproductive rights and the respective institutional practices. We consider it crucial to have a protective perspective ensuring conditions for the integrity of their bodies, but that simultaneously guarantees the exercise of rights pertaining to body and sexuality. Coordinating sexual and reproductive rights and sexual and reproductive health may be a promising path, especially for those adolescents who find greater obstacles in exercising these.
27
Morin, A., M. Rughetti, S. Rioux-Paquette e M. Festa-Bianchet. "Older conservatives: reproduction in female Alpine chamois (Rupicapra rupicapra) is increasingly risk-averse with age". Canadian Journal of Zoology 94, n. 5 (maggio 2016): 311–21. http://dx.doi.org/10.1139/cjz-2015-0153.
Testo completoAbstract (sommario):
In long-lived mammals, costs of reproduction may vary with age. The terminal investment hypothesis predicts greater reproductive effort as females approach the end of their life expectancy. We monitored 97 individually marked female Alpine chamois (Rupicapra rupicapra (L., 1758)) between 2007 and 2013 to determine how age-specific reproduction affected body mass and subsequent reproductive success. We captured and weighed females between April and August and monitored reproductive success from April to October through mother–kid associations. Reproductive success was strongly age-dependent and peaked at 70% for prime-aged females (4–7 years). Reproductive senescence began at 8 years, earlier than reported by other studies of ungulates. There was no clear evidence of reproductive costs in any age class. Reproductive success was very heterogeneous for old females, suggesting variability in the onset of senescence. Old females were less likely to reproduce in poor years despite being heavier than prime-aged females, suggesting reproductive restraint in late life rather than terminal investment. Female mass remained stable from May to August with no effect of lactation. Our results suggest that chamois reproductive strategy becomes increasingly conservative with age, resulting in no detectable costs of reproduction.
28
Dobson, F. Stephen, e Pierre Jouventin. "Testing Williams’ prediction: reproductive effort versus residual reproductive value (RRV)". Canadian Journal of Zoology 88, n. 9 (settembre 2010): 900–904. http://dx.doi.org/10.1139/z10-055.
Testo completoAbstract (sommario):
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.
29
Sukriani, Wahidah, e Riny Natalina. "Pengenalan Organ Reproduksi pada Remaja Putri di SMA Isen Mulang Kota Palangka Raya". PengabdianMu: Jurnal Ilmiah Pengabdian kepada Masyarakat 3, n. 2 (1 novembre 2018): 160–66. http://dx.doi.org/10.33084/pengabdianmu.v3i2.384.
Testo completoAbstract (sommario):
Talking about reproductive health is still considered sacred and taboo for some people in Indonesia. Reproductive Health is a topic that woman need to know to have the right information about the reproductive process that begins with the reproductive organs. Problems related to reproductive health often stem from a lack of information, understanding, and awareness to achieve a healthy state of reproduction With the right information, it is expected that adolescents have a responsible attitude and behavior regarding the reproductive process. The purpose of this community service is to introduce the reproductive organs in young women in SMA Isen Mulang Palangka Raya. The method used is to form peer counselors in the effort of the introduction of reproductive organs in young women in Isen Mulang High School Palangka Raya. The result of this service activity shows improvement of knowledge about female reproductive organs, reproductive organ function and how to keep reproductive organs, improving peer counseling skills in peer counseling on women's reproductive organs and the formation of students' attitude to maintain healthy reproduction organs.
30
Reekie, Edward G., Sonya Budge e 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, n. 2 (1 febbraio 2002): 140–50. http://dx.doi.org/10.1139/b01-146.
Testo completoAbstract (sommario):
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.
31
Rueger, T., T. A. Barbasch, M. Y. L. Wong, M. Srinivasan, G. P. Jones e P. M. Buston. "Reproductive control via the threat of eviction in the clown anemonefish". Proceedings of the Royal Society B: Biological Sciences 285, n. 1891 (21 novembre 2018): 20181295. http://dx.doi.org/10.1098/rspb.2018.1295.
Testo completoAbstract (sommario):
In social groups, high reproductive skew is predicted to arise when the reproductive output of a group is limited, and dominant individuals can suppress subordinate reproductive efforts. Reproductive suppression is often assumed to occur via overt aggression or the threat of eviction. It is unclear, however, whether the threat of eviction alone is sufficient to induce reproductive restraint by subordinates. Here, we test two assumptions of the restraint model of reproductive skew by investigating whether resource limitation generates reproductive competition and whether the threat of eviction leads to reproductive restraint in the clown anemonefish Amphiprion percula . First, we use a feeding experiment to test whether reproduction is resource limited, which would create an incentive for the dominant pair to suppress subordinate reproduction. We show that the number of eggs laid increased in the population over the study period, but the per cent increase in fed groups was more than twice that in unfed groups (205% and 78%, respectively). Second, we use an eviction experiment to test whether the dominant pair evicts mature subordinates, which would create an incentive for the subordinates to forgo reproduction. We show that mature subordinates are seven times more likely to be evicted than immature subordinates of the same size. In summary, we provide experimental support for the assumptions of the restraint model by showing that resource limitation creates reproductive competition and a credible threat of eviction helps explain why subordinates forego reproduction. Transactional models of reproductive skew may apply well to this and other simple systems.
32
Reekie, Edward G. "An explanation for size-dependent reproductive allocation in Plantago major". Canadian Journal of Botany 76, n. 1 (1 gennaio 1998): 43–50. http://dx.doi.org/10.1139/b97-160.
Testo completoAbstract (sommario):
This study examined whether variation in reproductive allocation with size could be explained by differences in the trade-off between reproduction and growth. Seeds from 42 half-sibling families were collected from sites differing in mowing frequency and availability of light, nutrients, and water. Six seedlings from each family were grown in controlled environments and photoperiod manipulations were used to control reproduction. Mass of vegetative and reproductive plants of the same family were compared to assess the trade-off between reproduction and growth. Families collected from habitats with a tall canopy were larger and experienced a greater decrease in growth with reproduction than families from habitats where mowing maintained a short canopy. Reproductive output showed no relationship with size, while reproductive allocation (capsule mass to vegetative mass) decreased with size. This decrease may be a direct consequence of the increase in reproductive cost with size. The increase in cost can be partially explained by increased allocation to reproductive support structures; large individuals produce capsules on more elongate scapes and have a lower capsule to scape ratio. Differences in size and morphology among habitats are presumably the result of selection to avoid damage in mown sites and to avoid shade and ensure pollination in sites with a tall canopy and reduced wind movement.Key words: allometry, life-history theory, size constraints, reproductive effort, reproductive cost.
33
Bennett, Nigel C., Christopher G. Faulkes e Cornelia Voigt. "Socially Induced Infertility in Naked and Damaraland Mole-Rats: A Tale of Two Mechanisms of Social Suppression". Animals 12, n. 21 (4 novembre 2022): 3039. http://dx.doi.org/10.3390/ani12213039.
Testo completoAbstract (sommario):
The naked mole-rat (Heterocephalus glaber) and the Damaraland mole-rat (Fukomys damarensis) possess extreme reproductive skew with a single reproductive female responsible for reproduction. In this review, we synthesize advances made into African mole-rat reproductive patterns and physiology within the context of the social control of reproduction. Non-reproductive female colony members have low concentrations of luteinising hormone (LH) and a reduced response of the pituitary to a challenge with gonadotropin releasing hormone (GnRH). If the reproductive female is removed from the colony, an increase in the basal plasma LH and increased pituitary response to a GnRH challenge arises in the non-reproductive females, suggesting the reproductive female controls reproduction. Non-reproductive male Damaraland mole-rats have basal LH concentrations and elevated LH concentrations in response to a GnRH challenge comparable to the breeding male, but in non-breeding male naked mole-rats, the basal LH concentrations are low and there is a muted response to a GnRH challenge. This renders these two species ideal models to investigate physiological, behavioural and neuroendocrine mechanisms regulating the hypothalamic-pituitary-gonadal axis. The recently discovered neuropeptides kisspeptin and RFamide-related peptide-3 are likely candidates to play an important role in the regulation of reproductive functions in the two mole-rat species.
34
Vargo, Edward. "Diversity of Termite Breeding Systems". Insects 10, n. 2 (12 febbraio 2019): 52. http://dx.doi.org/10.3390/insects10020052.
Testo completoAbstract (sommario):
Termites are social insects that live in colonies headed by reproductive castes. The breeding system is defined by the number of reproductive individuals in a colony and the castes to which they belong. There is tremendous variation in the breeding system of termites both within and among species. The current state of our understanding of termite breeding systems is reviewed. Most termite colonies are founded by a primary (alate-derived) king and queen who mate and produce the other colony members. In some species, colonies continue throughout their life span as simple families headed by the original king and queen. In others, the primary king and queen are replaced by numerous neotenic (nymph- or worker-derived) reproductives, or less commonly primary reproductives, that are descendants of the original founding pair leading to inbreeding in the colony. In still others, colonies can have multiple unrelated reproductives due to either founding the colonies as groups or through colony fusion. More recently, parthenogenetic reproduction has shown to be important in some termite species and may be widespread. A major challenge in termite biology is to understand the ecological and evolutionary factors driving the variation in termite breeding systems.
35
Mirando, M. A., e F. Stormshak. "REPRODUCTION SYMPOSIUM: External influences on reproductive neuroendocrinology1". Journal of Animal Science 92, n. 8 (1 agosto 2014): 3183–84. http://dx.doi.org/10.2527/jas.2014-8219.
Testo completo
36
Usacheva, E. "Reproductive choice in natural and assisted reproduction". Russian Juridical Journal, n. 3 (2021): 139–49. http://dx.doi.org/10.34076/20713797_2021_139.
Testo completo
37
Tkachenko, L. V., I. A. Gritsenko, K. Yu Tikhaeva, N. I. Sviridova, I. S. Gavrilova, V. A. Dolgova, A. S. Romanchenko e E. A. Savostova. "Abortion: reproductive choice or loss of reproduction?" Medical alphabet, n. 8 (11 giugno 2021): 44–48. http://dx.doi.org/10.33667/2078-5631-2021-8-44-48.
Testo completoAbstract (sommario):
This literature review of articles devoted to the problem of abortion and pre-abortion counseling has been carried out. The legal features of the development of the right to abortion at the request of a woman are outlined. The main stages in the development of the concept of perinatal psychology and pre-abortion counseling are described. The procedure for conducting pre-abortion counseling in the Russian Federation has been studied. The effectiveness of the existing algorithm was assessed and the prospects for further research aimed at studying and improving the effectiveness of pre-abortion counseling were outlined.
38
Renfree, Marilyn B. "WOMEN IN REPRODUCTIVE SCIENCE: Reproduction down under". Reproduction 158, n. 6 (dicembre 2019): F127—F137. http://dx.doi.org/10.1530/rep-19-0230.
Testo completoAbstract (sommario):
Australia is home to a unique assembly of mammals – the marsupials and monotremes. Despite this uniqueness, they have been largely ignored by the biomedical scientific community, and yet study of marsupials has contributed to modern research on reproduction, development, evolution, conservation, molecular and comparative genomics. My lifetime passion for these long-neglected Australian fauna has led to unexpected discoveries and insights that challenged assumptions and opened up new areas of international research. I used a range of disciplinary expertise to pursue the study of these unique mammals. My main experimental species has been the tammar wallaby that I have used as a model species to investigate and understand not only biomedical problems but also to provide knowledge that is critical for the continued conservation and management of Australia’s dwindling native mammals. This model provided more than a few surprises for me and my wonderful team of students, post-docs and collaborators about how hormones, genes and signalling molecules control reproductive biology and development in a wider context as well as how the interactions of the environment with mother and conceptus, with mother and fetus and mother and young ultimately control most aspects of successful reproduction in mammals.
39
Ferguson, P. R. "Book Review: Artificial Reproduction and Reproductive Rights". Medical Law International 1, n. 1 (marzo 1993): 123–24. http://dx.doi.org/10.1177/096853329300100109.
Testo completo
40
Day, B. N. "Reproductive biotechnologies: current status in porcine reproduction". Animal Reproduction Science 60-61 (luglio 2000): 161–72. http://dx.doi.org/10.1016/s0378-4320(00)00079-8.
Testo completo
41
Condit, Deirdre M. "Writing reproduction: Reproductive technologies and motherhood examined". Policy Sciences 27, n. 2-3 (1994): 287–94. http://dx.doi.org/10.1007/bf00999894.
Testo completo
42
Halliday, Tim. "Reproduction in mammals: Book 4. Reproductive fitness". Animal Behaviour 34 (febbraio 1986): 310–11. http://dx.doi.org/10.1016/0003-3472(86)90053-9.
Testo completo
43
Forslund, Helena, e Lena Kautsky. "Reproduction and reproductive isolation inFucus radicans(Phaeophyceae)". Marine Biology Research 9, n. 3 (aprile 2013): 321–26. http://dx.doi.org/10.1080/17451000.2012.731694.
Testo completo
44
Bahadur, G. "Ethical challenges in reproductive medicine: posthumous reproduction". International Congress Series 1266 (aprile 2004): 295–302. http://dx.doi.org/10.1016/j.ics.2004.01.105.
Testo completo
45
Pijnenborg, R. "Reproduction in mammals. Book 4. Reproductive fitness". European Journal of Obstetrics & Gynecology and Reproductive Biology 22, n. 5-6 (settembre 1986): 383. http://dx.doi.org/10.1016/0028-2243(86)90130-9.
Testo completo
46
Copello, Nadia Virginia. "Derecho a la salud reproductiva / Rigth to reproductive health". Revista Derecho y Salud | Universidad Blas Pascal, n. 3 (31 ottobre 2019): 197–205. http://dx.doi.org/10.37767/2591-3476(2019)13.
Testo completoAbstract (sommario):
El derecho a la salud reproductiva tiene una relación directa con el derecho a la vida, encontrándose amparado por los tratados internacionales de derechos humanos. Es razonable que existan limitaciones a estos derechos, puesto que no son absolutos, pero estas restricciones deben ser razonables. En el caso que analizaremos, la Corte Suprema de Justicia de la Nación adopta una posición intermedia respecto del derecho a la salud reproductiva. Para ello, partiendo de la finalidad de la ley 26.862, esto es: “garantizar el acceso integral a los procedimientos y técnicas médico-asistenciales de reproducción médicamente asistida”y, teniendo en cuenta los derechos en juego, resolvió en favor de la vigencia del derecho dentro de parámetros razonables.
The right to reproductive health is directly related to the right to life, being protected by international human rights treaties. It is reasonable that there are limitations to these rights, since they are not absolute, but these restrictions must be reasonable. In the case we will analyze, the Supreme Court of Justice of the Nation adopts an intermediate position regarding the right to reproductive health. To do this, based on the purpose of Law 26.862, this is: “guaranteeing comprehensive access to medico-assistance procedures and techniques of medically assisted reproduction” and, taking into account the rights at stake, resolved in favor of the validity of the right within reasonable parameters.
47
Vekhnik, Victoria Alexandrovna. "Reproductive activity of male edible dormice (Glis glis L., 1766) in the peripheral population". Samara Journal of Science 5, n. 2 (1 giugno 2016): 15–19. http://dx.doi.org/10.17816/snv20162103.
Testo completoAbstract (sommario):
The edible dormouse is a dendrobiont hibernating rodent breeding once a year. A peculiarity of the species biology is regular reproduction failure in non-mast years. In the center of the area it occurs due to the lack of male reproductive activity. In the studied population on the eastern periphery of the dormouse area previous studies proved the decisive role of mass resorption of embryos at females in the process. The dynamics of males reproductive activity and its impact on the reproduction were not considered previously in detail. In this work the periodicity and intensity of reproductive activity of males, depending on the age and phase of population cycle, was studied. Reproductive activity of the overwhelming majority of males was annually observed, the proportion of individuals not involved in reproduction did not exceed 6,7%. The age differences in the timing of beginning of the reproduction were revealed: yearlings came the first in the activity state and after them two-year and three-year and older individuals became active. The minimal duration of the mating period was observed in yearling males, the maximal - in two-year, which were also characterized by the longest individual periods of reproductive activity. As a result of sharp fluctuations in the population age structure two-year males are the most important group in reproduction, but the three-year and older individuals in mast years are also able to ensure the reproduction of the population. The characteristic feature of reproduction was noted at yearling males: they began reproduction depending on body weight. Fluctuations in the male reproductive activity during the active period do not play a significant role in the regulation of reproduction. Shorter duration of reproductive activity of yearling animals in the years of reproduction failure is compensated by the later beginning of reproduction of three-year and older individuals. Nonsynchronous participation in breeding of males of different age groups provides the involvement in reproduction of maximal number of animals.
48
Jannah, Miftachul, Pedvin Ratna Meikawati e Swasti Artanti. "Reproduksi Sehat, Remaja Sehat di Posyandu Remaja Pashmina". Jurnal ABDIMAS-HIP : Pengabdian Kepada Masyarakat 2, n. 2 (25 agosto 2021): 82–88. http://dx.doi.org/10.37402/abdimaship.vol2.iss2.152.
Testo completoAbstract (sommario):
Adolescents are people aged 12 to 24 years. Adolescence is a transition from childhood to adulthood. This means that the process of introduction and knowledge of reproductive health has actually started at this time. In simple terms, reproduction comes from the word "re" which means to return and "production" which means to make or produce. Reproductive health, as part of general health, is thus also a human right of every person, both men and women. Women's human rights are regulated in Law Number 39 of 1999 concerning Human Rights Article 3 paragraph (3) which states that everyone has the right to the protection of human rights and human freedoms without discrimination. Reproductive health according to Law Number 36 Year 2009 is a complete physical, mental and social condition, not merely free from disease or disability related to the reproductive system, function and process in men and women. The purpose of this community service is to provide reproductive health education about healthy reproduction, healthy adolescents, especially about anemia in adolescents, reproductive health and free sex in adolescents. Methods of reproductive health counseling carried out are (1) Socialization and licensing, (2) Conducting reproductive health counseling, (3) Evaluation of the results of reproductive health counseling activities by means of pre and post tests. The results of the reproductive health counseling activity showed high enthusiasm, indicated by the very good response of participants in receiving material on healthy reproduction, healthy adolescents and the willingness of participants to ask questions. The enthusiasm of the participants is expected to increase the understanding of girls and boys about the importance of healthy reproduction, healthy adolescents.
49
Vasilieva, N. A., e A. V. Tchabovsky. "Timing is the only thing: reproduction in female yellow ground squirrels (Spermophilus fulvus)". Canadian Journal of Zoology 92, n. 8 (agosto 2014): 737–47. http://dx.doi.org/10.1139/cjz-2014-0084.
Testo completoAbstract (sommario):
Based on 4-year field observations of yellow ground squirrels (Spermophilus fulvus (Lichtenstein, 1823)), we determined whether female reproductive effort, annual reproductive success, and survival were dependent on age, body condition, time of emergence from hibernation, and previous reproduction. The probability of weaning a litter did not vary with female age, body condition, time of emergence, or previous reproduction. Litter size, litter mass, and offspring survival did not vary with age, whereas individual offspring mass was lower in yearlings than in older females. Body condition upon emergence had no effect on litter size, litter mass, offspring mass, and survival. Reproduction did not influence female survival, physical condition upon emergence next spring, or subsequent reproductive efforts. The only factor that affected the extent of reproductive effort and offspring survival was the date of emergence: the later a female emerged, the lower the total and mean offspring mass, and fewer offspring survived. The modulation of reproduction in female S. fulvus by only the timing of vernal emergence and independent of other individual characteristics can be explained by the high costs of missed reproductive opportunity because of short longevity combined with low costs of reproduction when resources are abundant enough to meet both somatic and reproductive needs.
50
Barve, Sahas, Christina Riehl, Eric L. Walters, Joseph Haydock, Hannah L. Dugdale e 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, n. 1957 (18 agosto 2021): 20210579. http://dx.doi.org/10.1098/rspb.2021.0579.
Testo completoAbstract (sommario):
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.