Reproductive Benefits Research Articles

Masting ontogeny: the largest masting benefits accrue to the largest trees.

Both plants and animals display considerable variation in their phe- notypic traits as they grow. This variation helps organisms to adapt to specific challenges at different stages of development. Masting, the variable and synchronized seed production across years by a population of plants, is a common reproductive strategy in perennial plants that can enhance reproductive efficiency through increasing pollination efficiency and decreasing seed predation. Masting represents a population-level phenomenon generated from individual plant behaviors. While the developmental trajectory of individual plants influences their masting be- havior, the translation of such changes into benefits derived from masting remains unexplored. We used 43 years of seed production monitoring in European beech (Fagus sylvatica) to address that gap. The largest improvements in reproductive efficiency from masting happen in the largest trees. Masting leads to a 48-fold reduction in seed predation in large, compared to 28-fold in small trees. Masting yields an 6-fold increase in pollination efficiency in large, compared to 2.5-fold in small trees. Paradoxically, although the largest trees show the biggest reproductive efficiency benefits from masting, large trees mast less strongly than small trees. That apparently suboptimal allocation of effort across years by large plants may be a consequence of anatomical constraints or bet-hedging. Ontogenetic shifts in individual mast- ing behavior and associated variable benefits have implications for the reproductive potential of plant populations as their age distribution changes, with applications in plant conservation and management.

Temporal and spatial variation in reproductive benefits in a partial migrant.

In partial migrant systems, where residents and migrants coexist within a population, residents are commonly predicted to gain a reproductive advantage over migrants through priority access to high-quality territories and an earlier breeding start. Annual variation in reproductive benefits has been suggested to be important for the coexistence of both strategies in a population, as differences in wintering conditions experienced by the two strategies may result in a periodic reproductive advantage for migrants. However, the importance of spatial environmental variation for reproductive output in partially migrant populations remains largely unexplored. We investigated variation in the reproductive output of migrants and residents in a population of Swiss red kites (Milvus milvus) both temporally, across and within years, and spatially, along an elevational gradient. We gathered 4 years of reproductive data combined with 183 GPS-derived full annual cycles from individuals breeding in the Swiss Alpine foothills. At low, but not high, elevations, residents produced more fledglings than migrants. We also found evidence for annual variation in the reproductive advantage of the two strategies. Furthermore, while reproductive output did decline with a later breeding start, there was no difference in the start of breeding between the two migration strategies. The results of this study suggest that differences in reproductive output between migrants and residents in partial migrant populations can vary both due to the use of spatially distinct overwintering grounds and because the strategies are differently affected by spatial variables in the breeding area, such as elevation. The study emphasizes that spatial and temporal variation in reproductive benefits must be considered when predicting how migratory species will respond to future environmental change.

Successful adoption of non-orphaned infant by a parous, nursing female in yaki (Sulawesi crested macaque)

Abstract Adoption is an unusual behaviour across taxa, and for adoption to be successful, with the infant surviving to independence, the adoptive parent must be able to provide appropriate nutrition and care. Successful adoption has now been reported in several nonhuman primate species and here we add a case in wild yaki (Sulawesi crested macaque, Macaca nigra). We observed the adoption of an approx. 2-week-old infant by a female with her own approx. 3-week-old infant who went on to carry, nurse, and care for both infants until they both became independent. The adoptive and biological mother had each previously raised the same number of offspring (5). There was no evidence of aggressive transfer and we did not observe any attempts by the adopted infant’s biological mother to retrieve her. The biological mother went on to have another infant 8 months later while the adoptive mother was still caring for her other infant. This case may reflect some of the health costs and reproductive benefits of adoption for nonhuman primates.

Oral Contraceptives: Analyzing Effectiveness and Utilization Challenges to Improve Reproductive Health Outcomes

Background: Oral contraceptives (OCs) are widely used for preventing unintended pregnancies and offering various reproductive health benefits. However, their utilization is influenced by numerous factors, including access, education, and cultural beliefs. This meta-analysis aims to systematically review studies from 2019 to 2023 focusing on OC utilization patterns and effectiveness. Methods: A comprehensive search across PubMed, Scopus, and Google Scholar identified 50 relevant articles, from which nine studies were selected based on predefined criteria. Data extraction included demographic factors, adherence rates, side effects, access to OCs, and pregnancy outcomes. Quality assessments were performed using the Newcastle-Ottawa Scale and the Cochrane Risk of Bias tool, followed by statistical analysis using random-effects models. Results: The analysis revealed a pregnancy rate as low as 0.3% among perfect OC users, showcasing their high effectiveness. However, significant barriers persist, including poor adherence, discontinuation due to side effects, and disparities in access, particularly in low-income regions. Cultural perceptions and insufficient education further hinder optimal OC utilization. Conclusion: While OCs represent a reliable contraceptive method with substantial health benefits, ongoing challenges impede their optimal use. A multifaceted approach focusing on improved education, enhanced healthcare provider counseling, and targeted access initiatives is essential to increase OC utilization and reproductive health outcomes globally. Addressing these challenges will empower individuals to make informed family planning decisions, ultimately reducing unintended pregnancies and enhancing quality of life.

Increased offspring size and reduced gestation length in an ectothermic vertebrate under a worst-case climate change scenario

As global temperatures continue to rise, understanding the impacts of warming environments has become increasingly important. Temperature is especially relevant for ectothermic organisms which depend upon consistent and predictable annual temperature cycles for reproduction and development. However, additional research is required in this area to elucidate the potential impacts of climate change on future generations. To understand how projected increases in environmental temperatures may impact reproductive outcomes within natural populations of ectothermic vertebrates, we manipulated minimum ambient temperatures during gestation in Red-sided garter snakes (Thamnophis sirtalis parietalis). Wild snakes were collected in the Interlake region of Manitoba, Canada during their spring mating season and allowed to mate in controlled conditions. For the duration of gestation, mated females were placed into one of two ambient thermal conditions: temperatures emulating those found in the species’ natural habitat or temperatures with a consistent 5 °C increase to match end-of-century climate change projections. We recorded observations for each litter and all neonates resulting from controlled mating trials. We observed no difference in litter sizes or birth rates between thermal conditions. However, we observed a significant reduction in gestation length and significant increase to neonate body mass and body condition associated with increased ambient temperatures. These results suggest that increased minimum temperatures during gestation may confer reproductive benefits for the northern populations of this species even under the most extreme current modeled warming predictions. We discuss the broader implications of this effect, including possible negative ecological outcomes.

HSP70 inhibits CHIP E3 ligase activity to maintain germline function in Caenorhabditis elegans

The ubiquitin-proteasome system is crucial for proteostasis, particularly during proteotoxic stress. The interaction between heat shock protein 70 (HSP70) and the ubiquitin ligase CHIP plays a key role in this process. Our study investigates the C. elegans orthologs HSP-1 and CHN-1, demonstrating that HSP-1 binding decreases CHN-1 E3 ligase activity, aligning with the inhibitory effects observed in human HSP70-CHIP interactions. To explore the physiological significance of this inhibition, we utilized the HSP-1EEYD mutant, which binds CHN-1 without reducing its activity, expressed in C. elegans. Our results reveal that the HSP-1-CHN-1 interaction is critical for maintaining germline integrity under heat stress by preventing excessive turnover of essential reproductive proteins. In HSP-1EEYD nematodes, this protective mechanism is impaired, leading to disrupted stress-induced apoptosis, which is restored by CHN-1 depletion. Additionally, proteomic analysis identified DAF-18/PTEN as a potential CHN-1 substrate, which becomes destabilized when CHN-1 activity is not downregulated by HSP-1 during stress. Depleting DAF-18 significantly compromises the reproductive benefits observed from CHN-1 knockout in HSP-1EEYD mutants, suggesting that the maintenance of DAF-18 plays a role in the observed phenotypes. These findings highlight the importance of HSP-1 in regulating CHN-1 E3 ligase activity to preserve germline function under stress conditions.

Dynamics of multilevel alliances in St. Johns River, Florida, Tamanend's bottlenose dolphins (Tursiops erebennus) with respect to an epizootic unusual mortality event

AbstractDisturbance events can alter a community's association patterns, which can influence mating tactics. The St. Johns River (SJR) bottlenose dolphin (Tursiops erebennus) community was impacted by the 2013–2015 unusual mortality event (UME), caused by cetacean morbillivirus, through mortality and social network changes. We analyzed male alliance stability and behavior from April 2011 through March 2017 with respect to the UME. During the UME, 12 first‐order alliance dyads ended due to a partner's death or disappearance. Alliance tactics varied: forming second‐order alliances (n = 21 alliances; teams of first‐order alliances), forming first‐order alliances (n = 13 alliances) or remaining unallied after an alliance dissolved (n = 8 individuals). During‐ and post‐UME, fewer allied males formed second‐order alliances (55%) compared to pre‐UME (68%). While the UME likely indirectly influenced alliance behavior through demographic changes, female presence and breeding season consistently influenced alliance associations and consortships (cooperatively flanking a female), indicating a reproductive function for SJR alliances. Increased consortships when a second‐order partner was present suggests second‐order alliances may provide consortship support against rival males. These results enhance our understanding of multilevel alliance reproductive benefits and demonstrate the adaptability of male mating tactics in response to disturbances resulting in demographic changes.

EFFECTS OF SYMBIOTIC BACTERIA IN PATHOGENIC INTERACTIONS: THE CASE OF BATRACHOCHYTRIUM DENDROBATIDIS AND PSEUDOMONAS SP. IN AMPHIBIAN POPULATIONS

The decline in amphibian populations in recent decades may be linked to the occurrence of infectious diseases such as chytridiomycosis, which is caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd). It is known that symbiotic bacteria protect the host due to their inhibitory nature. However, how the population dynamics of amphibians is affected by additional effects provided by symbiotic bacteria has not been analyzed in depth. In this paper, a model is proposed to describe the interaction among susceptible amphibians, susceptible amphibians with symbiotic bacteria and amphibians with chytrid fungus. When the modeling takes into account the additional reproductive benefits that the symbiont Pseudomonas sp. grants to the host, multiple endemic equilibrium points can exist if [Formula: see text] ([Formula: see text] is the basic reproduction number for Bd). In this scenario, the existence of a subcritical bifurcation at [Formula: see text], which can occur in two different disease-free equilibrium points, gives rise to complex dynamics and stability scenarios. Particularly, the analysis of the model shows that a sudden increase of fungus-infected amphibians can occur even when [Formula: see text] due to bistability phenomena. In this scenario, the existence of a subcritical bifurcation, which translates for the fungus into colonization even for values of [Formula: see text] less than one, represents an advantage for the chytrid fungus Batrachochytrium dendrobatidis since the pathogen should benefit from remaining as close as possible to an endemic equilibrium. To control the fungal infection, [Formula: see text] must be reduced to a value below one until the endemic equilibrium points disappear. Finally, we show that the amphibian population can reach a critical population level close to an extinction scenario when [Formula: see text] increases.

Adult telomere length is positively correlated with survival and lifetime reproductive success in a wild passerine.

Explaining variation in individual fitness is a key goal in evolutionary biology. Recently, telomeres, repeating DNA sequences capping chromosome ends, have gained attention as a biomarker for body state, physiological costs, and senescence. Existing research has provided mixed evidence for whether telomere length correlates with fitness, including survival and reproductive output. Moreover, few studies have examined how the rate of change in telomere length correlates with fitness in wild populations. Here, we intensively monitored an insular population of house sparrows, and collected longitudinal telomere and life history data (16 years, 1225 individuals). We tested whether telomere length and its rate of change predict fitness measures, namely survival, lifespan and annual and lifetime reproductive effort and success. Telomere length positively predicted short-term survival, independent of age, but did not predict lifespan, suggesting either a diminishing telomere length-survival correlation with age or other extrinsic factors of mortality. The positive association of telomere length with survival translated into reproductive benefits, as birds with longer telomeres produced more genetic recruits, hatchlings and reared more fledglings over their lifetime. In contrast, there was no association between telomere dynamics and annual reproductive output, suggesting telomere dynamics might not reflect the costs of reproduction in this population, potentially masked by variation in individual quality. The rate of change of telomere length did not correlate with neither lifespan nor lifetime reproductive success. Our results provide further evidence that telomere length correlates with fitness, and contribute to our understanding of the selection on, and evolution of, telomere dynamics.

Factors Associated with Unplanned Pregnancy Among Youth at a Selected Hospital in Lesotho

Unplanned pregnancy amongst youth is a fundamental health problem that affects both developing and developed countries globally. There are various factors associated with unplanned pregnancy amongst youth and these factors have differing propagators. Unplanned pregnancies account for over half of total pregnancies in Lesotho; youth pregnancies contribute vast percentage overall. This study aimed to assess which factors associated are with unplanned pregnancy among youths who sought antenatal and postnatal care services at a selected government hospital in Lesotho. A descriptive cross-sectional design was used, and data was collected from a sample of 100 participants using a structured questionnaire. The results revealed that unplanned pregnancy among youths was associated with age, unemployment, lack of contraceptive use, sexual abuse, living in rural areas and lack of unplanned pregnancy prevention campaigns. The findings of this study support socio-ecological model which postulates that variety of factors influence health outcomes. We conclude that more needs to be done to improve access to formal education, availability and accessibility of unplanned pregnancy prevention campaigns and sexual and reproductive services. Reduction in unplanned pregnancy has several benefits not only to sexual and reproductive health but to life holistically. Sexual and reproductive health benefits include reduced maternal and neonatal morbidity and mortality and reduced abortions.

Strong marine heatwaves trigger flowering in seagrass

AbstractIn recent decades, the global intensification of marine heatwaves has impacted several ecosystems and species, including the endemic Mediterranean seagrass Posidonia oceanica. However, the scarcity of research in Eastern Mediterranean meadows, where historical and present thermal conditions differ from those of the Western Mediterranean, hampers our ability to draw comprehensive conclusions regarding the species' response to elevated sea temperatures. Here, we studied flowering patterns of P. oceanica meadows (3–15 m depth) of the Greek seas and assessed their potential association with marine heatwaves, while also examining the effects on plant growth associated with the transition from vegetative to sexual reproduction. To do so, we reconstructed flowering patterns from 2007 to 2021 across 58 meadows using lepidochronology and estimated summer marine heatwave metrics and categories using satellite sea surface temperature. The results revealed that flowering, while sporadic in most meadows (mean flowering frequency: 0.15), it was triggered by strong (Category II) summer marine heatwaves and a cumulative intensity exceeding 30°C days. Nevertheless, flowering density was low (mean flowering density: 11 inflorescences m−2) and not fuelled by frequency, intensity, or duration of marine heatwaves. Despite the potential long‐term benefits of sexual reproduction, annual rhizome production of flowering shoots decreased 1.5‐fold for at least 2 yr postflowering. This study uncovers the susceptibility of Eastern Mediterranean P. oceanica meadows, akin to their western counterparts, to marine heatwaves induced stress and its effects on reproductive strategies, raising concerns about the prospective plant growth and reproductive fitness to the escalating trend in marine heatwaves.

The Timing and Dose Effect of Acupuncture on Pregnancy Outcomes for Infertile Women Undergoing In Vitro Fertilization and Embryo Transfer: A Systematic Review and Meta-Analysis.

Background: Women undergoing in vitro fertilization and embryo transfer (IVF-ET) often utilize acupuncture to enhance pregnancy outcomes. Yet, the optimal timing for acupuncture sessions and the relationship between dosage and effect remain uncertain. Objectives: To investigate the impact of the timing and dosage of acupuncture on pregnancy outcomes, drawing on existing research. Methods: A comprehensive search of eight databases was conducted from their inception to January 14th, 2023, without restrictions on language. Only randomized controlled trials comparing acupuncture with either sham acupuncture or no adjuvant treatment were selected for inclusion. This meta-analysis assessed the efficacy of acupuncture in IVF-ET, analyzing the influence of varied timing and dosage on pregnancy outcomes. Subgroup analyses were undertaken to address any heterogeneity across the studies. Results: A total of 38 RCTs involving 5,991 participants were analyzed. In infertile women undergoing IVF fresh cycles, acupuncture performed during controlled ovarian hyperstimulation (COH) significantly increased the clinical pregnancy rate (CPR) (relative risk [RR] = 1.33, 95% confidence interval [CI]: 1.07-1.65, p = 0.01), whereas acupuncture administered either before COH or on the day of ET did not demonstrate reproductive benefits. Regarding frozen cycles, acupuncture before freeze-thaw embryo transfer (FET) significantly enhanced the CPR (RR = 1.71, 95% CI: 1.36-2.16, p < 0.00001) and live birth rate (LBR) (RR = 2.40, 95% CI: 1.20-4.79, p = 0.01). Improvements in CPR were observed across all dosage groups, but only the high-dosage group showed a significant increase in LBR (RR = 1.75, 95% CI: 1.05-2.92, p = 0.03). Conclusions: Timing and dosage of acupuncture are crucial factors affecting pregnancy outcomes in IVF-ET. For women undergoing IVF fresh cycles, acupuncture during COH yielded more significant reproductive benefits. In addition, acupuncture before freeze-thaw embryo transfer (FET) was associated with improved pregnancy outcomes in frozen cycles. Furthermore, higher dosages of acupuncture were linked to more favorable outcomes.

Bimodal alarm signals modulate responses to monomodal alarm signals in Camponotus modoc carpenter ants.

Distressed western carpenter ants, Camponotus modoc, produce alarm pheromone and substrate-borne vibrations. The alarm pheromone attracts nestmates but the effects of vibratory signals, or of bimodal pheromonal and vibratory signals, are not known. Worker ants of two Camponotus congeners reportedly stand still ("freeze") or run fast in response to engineered drumming vibrations inputted on plastic, but many responses to ant-produced vibratory signals on wood have not yet been investigated. Generally, orientating toward signalers under vertebrate predator attack seems maladaptive and not beneficial to ant colonies. We tested the hypotheses (1) that vibratory alarm signals cause freezing, rapid running but not attraction of nestmates, and (2) that bimodal alarm signals modulate responses to monomodal alarm signals, thereby possibly reducing predation risk. Laser Doppler vibrometry recordings revealed that the ants' vibratory signals readily propagate through ant nest lamellae, and thus quickly inform nest mates of perceived threats. With a speaker modified to record and deliver vibratory signals, we obtained drumming signals of distressed ants on a Douglas fir veneer, and bioassayed signal effects on ants in an arena with a suspended veneer floor. In response playback of vibratory signals, ants ran rapidly, or froze, but did not approach the vibratory signals. Exposed to alarm pheromone, ants frequently visited the pheromone source. However, concurrently exposed to both alarm pheromone and vibratory signals, ants visited the pheromone source less often but spent more time "frozen." The ants' modulated responses to bimodal signals seem adaptive but the reproductive fitness benefits are still to be quantified.

The revolution and future frontiers of reproductive management of dairy cattle

The 21-d pregnancy rate is determined by an interaction be­tween the AI service rate and pregnancies per AI (P/AI) and is a key performance indicator for the reproductive efficiency of dairy farms. Over the past 2 decades, the reproductive per­formance of lactating dairy cows increased. A greater under­standing of endocrinology and the physiology of lactating dairy cows generated fertility programs (the Presynch-Ovsynch and Double Ovsynch protocols for TAI) that increase the service rate and P/AI compared with detection of estrus. Previously, synchronization of ovulation in heifers was associated with poor reproductive performance compared with detection of estrus. Several modifications determined through randomized-controlled studies gave rise to the 5-d CIDR-Synch protocol that has similar and more P/AI when heifers are inseminated with conventional and sexed semen, respectively, compared with detection of estrus. A hierarchy of reproductive needs exists for dairy farms that require fulfillment before a new need can emerge. Dairy farms must have a high 21-d pregnancy rate and good heifer management before adopting other advanced re­productive technologies such as genomic selection, sexed and beef semen, and in vitro-produced embryos. Adopting these ad­vanced reproductive technologies benefits dairy farms, howev­er, challenges still exist that need further investigation through randomized-controlled experiments to maximize the benefits

Spiritual and Scientific Benefits of Iddah (Waiting Period) to Muslim Widow and Divorcee

Iddah is basically a waiting period, defined by Allah so that if any pregnancy has occurred just before the spouse’s death or separation, the fatherhood of that pregnancy should be clearly identified. With the advent of modern technology, the Islamic rule of Iddah is criticized stating that the months’ long wait in getting re-married is outdated. This research work investigates the adherence practices of widows and divorcee to this legislation of Iddah along with its associated benefits. The methodology followed the descriptive approach of literature review of jurisprudence books and regulations regarding Iddah. In addition, a survey was conducted to investigate 45 Muslim divorced and widow women’s experiences of Iddah. Thematic method was used to analyse the data. About 95% of participants showed understanding of Iddah as a mean of determining paternity, reconciliation and worshiping. Sadness and mourning were important features in divorce and widow cases, respectively and community and civic support were available during Iddah. During Iddah which represents 3-4 menstrual cycles, the repeated shedding of the endometrium necessitates complete repair and regeneration of the denuded surface. This may be viewed as an inevitable consequence of reproductive quality control and benefit in reproductive success when a widow or divorcee re-marry.

Observation of female-male mounting in the carrion crow

In the biological sciences, sexual behaviours in non-human animals are traditionally investigated in the context of reproduction and direct fitness benefits. While the evolutionary functions of non-conceptive sexual behaviours (‘socio-sexual behaviours’) remain less well explored, these interactions and displays have been suggested to be important for shaping and maintaining social relationships. Here, we report an observation of a captive female carrion crow, Corvus corone corone, mounting her co-housed male partner. We highlight the importance of more systematic research, reporting, and discussions of rarely observed behaviours in social evolution research, including considerations for behaviours that transcend binary or heteronormative frameworks, for a more comprehensive understanding of non-conceptive socio-sexual behaviours.

Looking at the bid picture: A framework for identifying reverse auctions in ecological systems.

Biological market theory can be used to explain intraspecific cooperation, interspecific mutualism, and sexual selection through models of game theory. These models describe the interactions between organisms as two classes of traders (buyers/sellers) exchanging commodities in the form of goods (e.g. food, shelter, matings) and services (e.g. warning calls, protection). Here, we expand biological market theory to include auction theory where bidding serves to match buyers and sellers. In a reverse auction, the seller increases the value of the item or decreases the cost until a buyer steps forward. We provide several examples of ecological systems that may have reverse auctions as underlying mechanisms to form mutualistic relationships. We focus on the yellow baboon (Papio cynocephalus) mating system as a case study to propose how the mechanisms of a reverse auction, which have the unintended but emergent consequence of producing a mutually beneficial outcome that improves collective reproductive benefits of the troop in this multi-female multi-male polygynandrous social system. For the yellow baboon, we posit that the "seller" is the reproductively cycling female, and the "buyer" is a male looking to mate with a cycling female. To the male, the "item for the sale" is the opportunity to sire an offspring, the price is providing safety and foraging time (via consortship) to the female. The "increasing value of the item for sale" is the chance of conception, which increases with each cycle since a female has resumed cycling post-partum. The female's sexual swelling is an honest indicator of that cycle's probability of conception, and since resident males can track a female's cycle since resumption, there is transparency. The males presumably know the chance of conception when choosing to bid by offering consortship. Across nature, this reverse auction game likely exists in other inter- and intraspecific social relationships. Considering an ecological system as a reverse auction broadens our view of social evolution and adaptations through the lens of human economic structures.

Reducing radicality in fertility-sparing surgery is associated with improved in vitro fertilization outcome in early-stage cervical cancer: A national retrospective study

ObjectiveFertility-sparing surgery (FSS) aims to achieve oncological outcomes that are non-inferior to radical treatment while preserving fertility and optimizing reproductive results. This study assesses in vitro fertilization (IVF) outcomes in early-stage cervical cancer survivors following FSS, comparing radical and non-radical approaches. MethodsThis retrospective analysis used data from Hungary's National Health Insurance Fund (2004–2022) on patients who underwent IVF treatment following FSS for early-stage cervical cancer at ten Hungarian fertility clinics. Patients were classified into radical and non-radical surgical groups, with the uterine arteries being spared in the non-radical procedures. RStudio (R software version: 4.2.2) was used for statistical analysis. Student's t-test was used to compare group means, and Fisher's exact test was applied to assess independence and distributions between categorical variables, and to estimate odds. ResultsThe study analyzed data from 122 IVF treatment cycles involving 36 patients. The non-radical group had a significantly higher live birth rate (83%, 5/6 compared to the radical group (17%, 5/30). Additionally, the non-radical group had a significantly higher implantation rate and cumulative live birth rate per oocyte retrieval (37%, 7/19 and 55%, 6/11 respectively) compared to the radical group (8%, 12/148 and 6%, 5/80 respectively). ConclusionThis is the largest study to evaluate IVF outcomes in young cervical cancer survivors who have undergone FSS. The findings suggest that less radical procedures are associated with significantly better IVF outcomes. These results emphasize the importance of considering oncological safety and reproductive outcomes together when choosing FSS for early-stage cervical cancer patients. It also highlights the reproductive benefits of performing less radical surgery.

Survival costs and benefits of reproduction: A register-based study in 20th century Estonia.

Patterns of individual variation in lifespan and senescence depend on the associations between parental survival and reproductive rates. We studied the associations between parity and survival among 579,271 Estonians born between 1905 and 1945 and in a cohort with a completed lifespan born in 1905-1927. For this cohort, selection for increased lifespan operated on both sexes, but it was stronger in men than in women. However, the median lifespan increased between the subsequent cohorts in women but stagnated in men. Selection for longer lifespan was caused by the below-average lifespan of individuals with no or single offspring. Despite a general positive selection for lifespan, survival costs of reproduction were also detected among a relatively small proportion of individuals with high parities, as mothers of two and fathers of two and three children had the highest median lifespans. Fathers of more than six children had better survival than fathers of few children in their reproductive age, but this association reversed after age 70. The reversal of this association between survival and parity at old age indicates that relative mortality risks between those with lower versus higher parities change across ages, as predicted by the antagonistic pleiotropy theory of aging.

Apomixis and the paradox of sex in plants.

The predominance of sex in eukaryotes, despite the high costs of meiosis and mating, is still an evolutionary enigma. Many theories have been proposed, none of them being conclusive on its own, and they are partly not well applicable to land plants. Sexual reproduction is obligate in embryophytes for the great majority of species. This review will compare the main forms of sexual and asexual reproduction in ferns and angiosperms, based on the generation cycling of sporophyte and gametophyte (leaving vegetative propagation aside). The benefits of sexual reproduction for maintenance of genomic integrity compared to asexuality will be discussed in the light of developmental, evolutionary, genetic and phylogenetic studies. Asexual reproduction represents modifications of the sexual pathway, with various forms of facultative sexuality. For sexual land plants, meiosis provides direct DNA repair mechanisms of oxidative damage in reproductive tissues. The ploidy alternations of meiosis-syngamy cycles, and prolonged, multicellular stages in the haploid phase in the gametophytes provide a high efficiency of purifying selection against recessive deleterious mutations. Asexual lineages might buffer effects of such mutations via polyploidy, and can purge the mutational load via facultative sexuality. The role of organelle-nuclear genome compatibility for maintenance of genome integrity is still not well understood. The costs of mating are in plants in general low because of predominant hermaphroditism. Phylogenetic patterns in the Archaeplastid clade suggest that high frequencies of sexuality in land plants are concomitant with a stepwise increase of intrinsic and extrinsic stress factors. Furthermore, expansion of genome size in land plants would increase the potential mutational load. Sexual reproduction appears to be essential for keeping long term genomic integrity, and only rare combinations of extrinsic and intrinsic factors allow for shifts to asexuality.