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Maternal age can influence reproductive success and offspring fitness, but the timing, magnitude and direction of those impacts are not well understood. Evolutionary theory predicts that selection on fertility senescence is stronger than maternal effect senescence, and therefore, the rate of maternal effect senescence will be faster than fertility senescence. We used a 36-year study of northern elephant seals (Mirounga angustirostris) to investigate reproductive senescence. Our dataset included 103,746 sightings of 1203 known-age female northern elephant seals. We hypothesized that fertility (maternal reproductive success), offspring survival and recruitment into the breeding population, and male offspring production would decline with advanced maternal age. Furthermore, we hypothesized that older females would shorten their moulting haul out to allow for more time spent foraging. We found evidence for both fertility and maternal effect senescence, but no evidence for senescence impacting offspring recruitment or sex ratio. Breeding probability declined from 96.4% (95% CI: 94.8%-97.5%) at 11 years old to 89.7% (81.9%-94.3%) at 19 years old, and the probability of offspring survival declined from 30.3% (23.6%-38.0%) at 11 years old to 9.1% (3.2%-22.9%) at 19 years old. The rates of decline for fertility and maternal effect senescence were not different from each other. However, maternal effect senescence had a substantially greater impact on the number of offspring surviving to age 1 compared to fertility senescence. Compared to a hypothetical non-senescent population, maternal effect senescence resulted in 5.3% fewer surviving pups, whereas fertility senescence resulted in only 0.3% fewer pups produced per year. These results are consistent with evolutionary theory predicting weaker selection on maternal effect than fertility senescence. Maternal effect senescence may therefore be more influential on population dynamics than fertility senescence in some systems.

People often interact with groups (i.e., ensembles) during social interactions. Given that group-level information is important in navigating social environments, we expect perceptual sensitivity to aspects of groups that are relevant for personal threat as well as social belonging. Most ensemble perception research has focused on visual ensembles, with little research looking at auditory or vocal ensembles. Across four studies, we present evidence that (i) perceivers accurately extract the sex composition of a group from voices alone, (ii) judgments of threat increase concomitantly with the number of men, and (iii) listeners sense of belonging depends on the number of same-sex others in the group. This work advances our understanding of social cognition, interpersonal communication, and ensemble coding to include auditory information, and reveals peoples ability to extract relevant social information from brief exposures to vocalizing groups.

Infanticide and adoption have been attributed to sexual selection, where an individual later reproduces with the parent whose offspring it killed or adopted. While sexually selected infanticide is well known, evidence for sexually selected adoption is anecdotal. We report on both behaviors at 346 nests over 27 y in green-rumped parrotlets (Forpus passerinus) in Venezuela. Parrotlets are monogamous with long-term pair bonds, exhibit a strongly male-biased adult sex ratio, and nest in cavities that are in short supply, creating intense competition for nest sites and mates. Infanticide attacks occurred at 256 nests in two distinct contexts: 1) Attacks were primarily committed by nonbreeding pairs (69%) attempting to evict parents from the cavity. Infanticide attacks per nest were positively correlated with population size and evicting pairs never adopted abandoned offspring. Competition for limited nest sites was a primary cause of eviction-driven infanticide, and 2) attacks occurred less frequently at nests where one mate died (31%), was perpetrated primarily by stepparents of both sexes, and was independent of population size. Thus, within a single species and mating system, infanticide occurred in multiple contexts due to multiple drivers. Nevertheless, 48% of stepparents of both sexes adopted offspring, and another 23% of stepfathers exhibited both infanticide and long-term care. Stepfathers were often young males who subsequently nested with widows, reaching earlier ages of first breeding than competitors and demonstrating sexually selected adoption. Adoption and infanticide conferred similar fitness benefits to stepfathers and appeared to be equivalent strategies driven by limited breeding opportunities, male-biased sex ratios, and long-term monogamy.

We provide the first estimates of survival and reproductive rates for a population of the Gambian Epauletted Fruit Bat Epomophorus gambianus in Ghana. We focused on a large colony of ca. 5,000 bats over 3 years to estimate population parameters including population size, birth rates, survival, and sex ratios for this species. Reproduction chronology was confirmed as seasonal bimodal polyestry, with births occurring in March/April and August/September each year. The estimated birth rate was 0.89 (95% CI = 0.85 to 0.92) per reproductive season. The overall sex ratio (female to male ratio) of the study population was male-dominated (0.69, 95% CI = 0.64 to 0.75), but female-biased for adults (62% female, χ21 = 42, P < 0.0001), and showed temporal and age-specific variations. By radiotracking 60 bats for 10 months, we obtained the first estimates of minimum monthly survival for this species as 0.81 (95% CI = 0.74 to 0.86), but this could be an underestimate due to possible undetected emigration of tagged bats. [ABSTRACT FROM AUTHOR]

This study empirically tests the role of population structure in the process of digital financial inclusion empowering the upgrading of consumption structure by taking 248 prefecture-level cities between 2013 and 2019 as the research objects. The results of this study are as follows. First, digital financial inclusion will expand the scale of consumption. Second, digital financial inclusion can promote the upgrading of consumption structure. Third, population structure will regulate the promotional effect of digital financial inclusion on the upgrading of consumption structure. Specifically, child dependency ratio has a positive moderating effect on digital financial inclusion-driven the upgrading of consumption structure. Moreover, sex ratio has a positive moderating effect on digital financial inclusion-driven the upgrading of consumption structure. Therefore, it is suggested that vigorously promote and develop digital financial inclusion, implement and improve the three-child policy, and expand the elderly consumer industry to better promote consumption upgrading. [ABSTRACT FROM AUTHOR]

The intensity and direction of sexual selection are intricately linked to the social and ecological context. Both operational sex ratios (OSRs) and population densities can affect the ability of males to monopolize resources and mates, and thus the form and intensity of sexual selection on them. Here, we studied how the mating system of the promiscuous and strongly sexually dimorphic fruit fly Drosophila prolongata responds to changes in the OSR and population density. We recorded groups of flies over five days and quantified territory occupancy, mating success (MS) and competitive fertilization success. Although sexual selection was stronger under male-biased than even OSRs but unrelated to density, realized selection on morphological traits was higher under even OSRs and increased with density. Larger and more territorial males achieved both higher MS and competitive fertilization success, but only under even OSRs. Our combined results also support a shift in the mating system from territorial contest competition to scramble competition under male-biased OSRs and potentially at low density, where there was no clear contribution of the measured traits to reproductive success. Our study emphasizes the limitations of traditional selection metrics and the role of the socio-ecological context in predicting adaptation to a changing environment. [ABSTRACT FROM AUTHOR]

Very little is known about the reproductive behaviours of whale sharks (Rhincodon typus). Here, we describe field observations of courtship behaviour by a whale shark at Ningaloo Reef, Western Australia. We witnessed and recorded following and biting behaviours by a sexually mature male of a smaller female. Following and biting are common events during courtship and copulation of other species of elasmobranchs. Our observations are consistent with earlier reports of courting behaviours in whale sharks provided by fishers, the pilot of a light plane and observations of courtship by a sexually mature male towards females held in aquaria. [ABSTRACT FROM AUTHOR]

The ability to secure food for offspring and withstand the cost of reproduction favors high-quality mothers that overproduce the larger sex, typically sons, only if they will receive adequate food, as this should enhance these sons' fitness returns. However, high-quality daughters ensure that grandoffspring receive quality parental care and may possess greater reproductive value than their brothers, favoring daughters also from high-quality mothers. Using a mixed cross-fostering approach, we investigated effects of early rearing conditions, covariance between breeders and their genetic parents in parental quality, and primary offspring sex ratios in Carolina wrens. In this socially and genetically monogamous bird, sons grew larger than daughters, paternal food provisioning impacted the condition and recruitment of sons but not daughters, and females overproduced sons when paired with males that provisioned at a high rate, reflecting females' anticipation of the quality of the rearing environment. Components of reproductive potential, including total fecundity, were inherited matrilineally, and all else being equal, females in better condition produced larger-than-average clutches biased toward daughters, who eventually produced larger-than-average clutches themselves. Sex ratios therefore varied with components of parental investment but in opposing directions for matrilineally inherited and environmental effects, suggesting that multiple countervailing selective forces shape sex ratio variation. [ABSTRACT FROM AUTHOR]

Population characteristics of the Barbary sheep Ammotragus lervia, the only wild caprine in Northwest Africa, were investigated in a captive population located in a 150-ha fenced area within the Amassine reserve, Morocco, created for promoting wildlife watching tourism. We analysed the population trend during 20 years since the introduction of 10 individuals in 1999. Using direct counting in March-April 2016 to 2019, before herd dispersal, we assessed population size, age-sex structure, birth and survival rates. We estimated survival rates from mortality analysis using exponential regression models. The population size exhibited fluctuations over time expressed by significant exponential equations. We observed three successive phases corresponding each to a fast-growing period followed by a sharp decline. Estimated population density ranged from 0.25 to 0.41 ind. ha−1. Adult sex ratio varied from 67 to 91 rams per 100 ewes. Juveniles and subadults comprised 27–43 % of the population, and adults, rams and ewes, represented 26–31 % and, 29–45 %, respectively. Birth rate varied from 14 to 73 lambs per 100 ewes. The survival rate during the postnatal year approximated 35 %. For adult rams, it was around 69 % year−1. Our findings would be helpful for developing a sustainable population management plan, and assessing potential reintroduction/restocking in other areas. [ABSTRACT FROM AUTHOR]

Male horseflies have low capture rates in Malaise traps, a widely documented pattern observed in numerous ecological studies. We present findings from a specific locality in Ecuador where a departure from this established pattern is observed. In this locality, males accounted for 59.14% of Tabanidae captures. The disruption in capture patterns observed using Malaise traps represents an uncommon feature in the scientific literature and during collections conducted over eight years in Ecuador. Despite the inherent limitations of Malaise traps in capturing male horseflies, it is possible that under specific conditions, such as the presence of optimal aggregation areas for horseflies, Malaise traps may enhance the capture efficiency of males. Additionally, we provide a detailed discussion on the disruption and disparity in capture sex proportions in Tabanidae, commonly reported in the scientific literature. [ABSTRACT FROM AUTHOR]

The evolution of mating systems reflects a balance of the often-conflicting interests of males and females. Polygyny, a mating system in which males have multiple mates, presents a fitness benefit to males, but the consequences for females are less clear. Females with polygynous social mates may suffer reduced fitness, especially secondary females who typically receive less male support. We used 32 yr of detailed reproductive data on a population of Savannah sparrows (Passerculus sandwichensis) breeding on Kent Island, NB, Canada, to investigate the effects of females' social mating status on 6 indices of female fitness: survival, clutch size, fledging success, number of fledglings produced per nest and annually, and recruitment of offspring. Secondary females produced fewer fledglings per nest and annually than did monogamous or primary females, and their young were less likely to recruit into the breeding population. Yearling secondary females also had lower survival rates than older secondary females. Combined with higher rates of partial brood loss among secondary females, our results suggest that secondary females are unable to provide enough care to consistently fledge all nestlings in their broods, likely due to reduced male provisioning. Given that the sex ratio of breeders in the population is female-biased, we suggest that polygyny persists despite its fitness costs because some females must mate polygynously to "make the best of a bad situation." Our study demonstrates the value of detailed, long-term population monitoring data for understanding mating systems and using multiple indices of fitness to analyze the costs of polygyny. [ABSTRACT FROM AUTHOR]

The sustainable use of wildlife is foundational to the success of the North American model of wildlife conservation. Harvest management often is shaped through both species biology and public desires. The long timespan it takes males of most ungulate species to reach peak weapon size has created a situation in harvest management in which harvest strategies cannot prioritize both generous hunter opportunity and opportunities to pursue large‐weaponed males; therefore, current harvest paradigms prioritize one at the expense of the other. In contrast to other species, pronghorn (Antilocapra americana) attain the majority of their peak horn size early in life. The rapid development of horns relative to their age may allow for liberal harvest without sacrificing the opportunity for hunters to harvest males with large horns. We evaluated the influence of sex ratios and average age of harvested males on the average horn size of harvested male pronghorn from 2019 to 2022 in 9 hunt areas in Wyoming, USA. Although mean age of harvested males was negatively affected by rate of harvest, increases in mean age at harvest led to only slight increases in mean horn size (i.e., a 1‐year increase in mean age increased mean horn size by 2.1 cm [~1 inch]). The proportion of the harvest composed of large‐horned males was not influenced by mean age of harvest or sex ratio of the population. Based on simulated populations, increasing harvest led to an increase in the number of large‐weaponed pronghorn in the harvest—a relationship that existed for bighorn sheep (Ovis canadensis) and elk (Cervus canadensis) but only at low to moderate rates of harvest. The comparatively young age that pronghorn attain near‐peak horn size alleviates what is otherwise a tradeoff between hunter opportunity and managing for large horn size that is evident in management of other ungulate species. Though rarely a reality in management for large ungulates, for pronghorn, liberal harvest may be possible while still providing opportunity to harvest males with large horns. [ABSTRACT FROM AUTHOR]

Background: Several African studies have focused on the clinical features of lupus in black skin, yet the immunological, biological, and imaging profile of the disease remains poorly described in Côte d'Ivoire. Objective: The aim of this study was to investigate the epidemiological, clinical, paraclinical and evolutionary aspects of lupus patients followed at the Dermatology Department of a University Hospital. Methods: This was a cross-sectional, retrospective study of patients received at the dermatology and venereology department of a university hospital over a six-year period. The diagnosis was based on the European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) classification criteria. Results: We included 72 lupus patients. The sex ratio was 9/1 (female-to-male) and the mean age was 37.9 years. Mucocutaneous manifestations were noted in 66% of the patients and were dominated by discoid lupus (88.9%). Rheumatological involvement was the most common extra-dermatological manifestation (21.8%). The main antibodies found were AAN (73.19%), anti-DNAn (45.8%), and anti-Sm Ac (27.8%). The main treatments used were hydroxychloroquine (98%), corticosteroids (37.5%), immunosuppressants (47.2%), and sun protection. Progression was favorable in 37.5%, and 51.2% of the patients were lost to follow-up. Conclusion: Lupus erythematosus is a rare pathology at the dermatology department, with a female predominance. Its main treatment is hydroxychloroquine, and many patients are lost to follow-up. [ABSTRACT FROM AUTHOR]

Tannic acid, as a polyphenol, is widely present in dicotyledonous plants and angiosperms. The study found that tannins could affect the ovarian development of Brandt's voles. However, the specific effects of tannic acid on reproduction and its underlying mechanisms are still poorly understood. Therefore, this study explored the effects of tannic acid on the reproduction of Brandt's voles. We treated female Brandt's voles from four weeks postpartum with varying tannic acid doses (0 (control), 0.3% (low dose) or 0.6% (high dose) tannic acids) until 8 weeks (puberty) and 13 weeks (sexual maturity)). Ovarian specimens were collected for immunohistochemical analysis and RT-PCR. The treated Brandt's voles were mated with male Brandt's voles of the same age and we recorded the number of embryos, litters and the male to female ratio of the offspring. We found that the female Brandt's voles in the low-dose tannic acid group had enhanced reproductive abilities, characterized by reduced follicular atresia and increased numbers of embryos and litters of offspring. The different doses of tannic acid altered the female-male ratio of the Brandt's voles' offspring. While the low-dose of tannic acid enhanced the level of ovarian autophagy by significantly increasing the expression of Beclin1 and LC3 proteins in the ovaries of the Brandt's voles during sexual maturity. In short, tannic acid can promote the reproduction of Brandt's voles by affecting the level of ovarian autophagy and improving the development of follicles. Tannins can boost the reproduction of Brandt's voles. [ABSTRACT FROM AUTHOR]

Dioecious plants have different needs for natural resources due to sex differences, which can lead to skewed sex ratios. Clonal growth facilitates and optimizes resources of clonal plants. So, dioecious plants show inter-sex differences in clonality. However, it is unclear how the clonality varies between female and male plants when they exhibit skewed sex ratios along an altitudinal gradient. Here, we investigated the sex ratio and clonality of Hippophae tibetana populations growing at three altitudes in the alpine meadow. We founded that (i) H. tibetana growing at different altitudes mainly consisted of II and III age classes, with a significantly male-biased sex ratio observed at a low altitude, a female-biased ratio at a middle altitude, and no significant sex-bias in the population at a high altitude. (ii) The population distribution was generally random at both low and high altitudes, while clustered at middle altitudes with an increasing scale. Meanwhile, the male and female populations at a low altitude showed a negative correlation, while the male and female at a middle altitude only showed a negative correlation at a 0–0.5 m scale, and spatial independence with increasing scales. (iii) Females of H. tibetana had a strong clonal capacity than male plants at a middle altitude, while the opposite was observed at a low altitude. The number of males of H. tibetana growing at a low altitude and with higher clonal diversity were higher than females at mid altitude. Our findings will contribute to the understanding of the sexual dimorphism exhibited by dioecious plants as well as the importance of a clonal adaptation in response to environmental change. [ABSTRACT FROM AUTHOR]

Sex ratio at birth (SRB) is a simple, noninvasive way to monitor the reproductive health of a population. Apparently only a few studies have assessed the relationship between ambient air pollution and SRBs. The studies that investigated this relationship have yielded inconsistent results. Ambient air pollution levels, including particulate matter (PM2.5) levels, have decreased in Taipei city after a mass rapid transit (MRT) system commenced operations in 1996. The aim of this study was to determine whether the changes in levels of PM2.5 after the implementation of the MRT system in Taipei may have influenced the concurrent alterations noted in the SRB. In order to assess this potential association, annual numbers of male and female births were obtained from Taiwan’s Department of Household Registration, Ministry of Interior Affairs from 1992 to 2023. Mean yearly SRBs were calculated for 4 time periods, 1992–1995, 1996–2004, 2005–2015, and 2016–2023. Linear logistic regression was employed to evaluate the variation in officially reported PM2.5 levels during those periods and alterations in the ratios. The ratios for time periods 1 to 4 were 52.61%, 52.22%, 51.78%, and 51.67%, respectively. Compared to Period 1 (pre-MRT), the odds ratios for Periods 2, 3, and 4 were 0.98 (0.97–0.99), 0.97 (0.96–0.98), and 0.96 (0.95–0.98), respectively. The trend toward the decreased SRB was found to be gradual but significant. [ABSTRACT FROM AUTHOR]

This study aimed to describe reproductive ecology based on morphological aspects of Peckoltia oligospila in stream rapids, eastern Amazon. A total of 186 fish (75 males and 111 females) were collected. The sex and gonadal maturity stage of these specimens were obtained based on histological characteristics of the gonads. The sex ratio, gonado‐somatic index (GSI), relative frequency of the different maturity stages, size at first sexual maturation, condition factor of the population, and fluviometry were evaluated during the study. There was a significant female frequency during the study. The population exhibited positive allometric growth without differences between sexes. GSI and relative frequency showing a reproductive period synchronized in February, and the species exhibited parcelated spawning. L50 was estimated at 5.85 and 7.39 cm for females and males, respectively. There were significant differences in the condition factor only in females that showed a highest value in August. Thus, based on the results P. oligospila has an intermediate strategy between the opportunistic and equilibrium strategies. [ABSTRACT FROM AUTHOR]

Cycas fairylakea is an endemic and Level-One National Key Protected Wild Plant in China. It is distributed in the Meilin Reservoir and Tanglangshan Country Park in Shenzhen. This study investigated two newly discovered wild populations in Taishan and Yangjiang, Guangdong Province. The forest community characteristics and population structure of these newly discovered populations remain unknown, and the sex ratio as well as the species' responses to environmental factors have never been reported, despite their importance for the in-situ conservation of this Cycad. We conducted a comprehensive investigation of the ecological traits (soil properties, community characteristics, and phylogenetic diversity) and population characters (size, age structure, sex ratio, and spatial pattern) of C. fairylakea and determined the impact of environmental factors on the age structure and sex ratio. The results showed that the species number and composition of the two communities differed, yet no significant differences were observed in the plant diversity indices, with close phylogenetic affinities among species. Moreover, the sex ratio, determined by the MADS-Y marker, was relatively balanced. The age structure of the two populations exhibited a "reverse-J" shape, and the survival curves were of the Deevey's type III, indicating low natural regeneration capacities with high mortality in the early stage. Redundancy analysis identified the soil properties as constraining factors of the C. fairylakea sex ratio, while climate factors and community species diversity and evenness indices positively impacted the sex ratio. The combined effects of soil, climate, topography, and shrub layer plant diversity were the main factors influencing the age structure and sex ratio of the C. fairylakea populations. A balanced sex ratio ensures reproductive capacity, which maintains population stability. However, the structural and numerical characteristics of C. fairylakea in the two regions are constrained by environmental pressures. The implementation of well-considered artificial conservation strategies and the safeguarding of the habitat are intended to bolster the survival rate of the seedlings, promote the healthy growth of middle-aged individuals, and maintain the sustained stability of the natural population of C. fairylakea. [ABSTRACT FROM AUTHOR]

Previous studies have achieved success in obtaining cultured juveniles of the sea urchin Salmacis sphaeroides, but few have reported their reproduction potential and development rates. This comprehensive study examined the spawning potential of broodstock and described embryonic, larval and juvenile development. The broodstock consisted of wild-caught specimens from Singapore's coastal waters that were regularly provided a mixed animal-plant diet comprising 3 g prawn and 3 g corn. Gametes were obtained using 0.5 M of potassium chloride (KCl) injection into the coelomic cavity. Fertilization rates of the 32 spawning attempts varied from 42.9% to 100%. Hatched larvae were subsequently reared with a density of 0.5 larvae ml−1 in 50 µm filtered seawater at 28°C and fed 20,000 cells ml−1 of Tisochrysis lutea once every 2 days. Despite the presence of natural biofilms as settlement cues, the settlement rates in culture were very low and variable (2.08–9.78%). The majority of juvenile S. sphaeroides from F1 and F2 generations was sexually mature at ≥35 mm in test diameter, and the sex ratios were female-biased, ranging from 1:1.14 to 1:8. Findings from this study open up new opportunities for developing tropical sea urchin cultures under controlled rearing systems that can guarantee production. IMPACT STATEMENT: Salmacis sphaeroides metamorphosis was induced using natural biofilms but had poor settlement rates Recommendation to induce spawning only in adult Salmacis sphaeroides that are at ≤35 mm in test diameter and at least 10 months old Female-biased sex ratios of lab-grown F1 and F2 generations [ABSTRACT FROM AUTHOR]

Striostrea prismatica is an oyster of commercial importance present in several locations of the Eastern Tropical Pacific. The objective of this study was to evaluate the sex ratio, gametogenic cycle, maturity stages, size at first maturity (SH50) and monthly variation in the condition index of this species over the course of an annual cycle on the coast of Colima, Mexico. The oysters found in the shallow sublittoral areas near Faro de Campos were larger and heavier than those in Cuyutlan lagoon. The sex ratio was significantly shifted towards males at both sites. The gonad showed a prolonged undifferentiated stage lasting from November to April, a spawning period limited to June through October and an extended post-spawning period from August to December. SH50 was higher in females in the lagoon as well as in the shallow sublittoral. Monthly variation in surface temperature and chlorophyll a in both study areas only correlated with the condition index of populations in the shallow sublittoral and inner lagoon in the months of lowest temperatures and highest chlorophyll a. These findings provide basic information on the reproductive cycle of rock oysters that may prove useful for the development of improved harvesting practices in the study region. [ABSTRACT FROM AUTHOR]

Since relatively dense assemblages of nereidid worms were discovered from a unique habitat within the decaying fronds of the mangrove palm Nypa fruticans, we conducted a one-year survey from September 2015 to September 2016 at six sites in Setiu Wetlands, Malaysia, to clarify the species composition of the nereidid assemblages and the life history of the dominant species. The majority of specimens collected from the plant body (507 out of a total 678 specimens) belonged to Namalycastis sp. with remaining specimens belonging to Namanereis sp. (n=168), Namalycastis rhodochorde (n=1), and Perinereis aibuhitensis (n=2). Specimens of P. aibuhitensis (n=2) and Dendronereis sp. (n=2) were also collected from sediments around the palm trees. The taxonomic accounts of two Namalycastis spp. and Perinereis aibuhitensis are provided here. The life history of the dominant species Namalycastis sp. is evaluated based on the population characteristics. This species is gonochoric, with the sex ratio close to 1:1. The ovigerous females were found throughout the year, with their body width (BW) ranging from 1.3 to 4.8 mm. The ovigerous rate (no. of ovigerous females/no. of worms larger than the minimum ovigerous female) was lowest in February and March 2016 (8–9%) and highest from July to November 2016 (23–29%), when the ovigerous females had the largest coelomic oocytes of 100–120µm in diameter. Probable epitokes with additional neuropodial sesquigomph spinigers occurred most abundantly in November 2015 (21% of adults), which was also the only month when a mature male with mature spermatozoa appeared. Few juveniles with BW of less than 1.3 mm occurred from February to July, whereas large adults with BW of more than 3.5 mm occurred from May to November. These results suggest semelparous reproduction with peak spawning in November, coinciding with low salinity during the north-east monsoon. [ABSTRACT FROM AUTHOR]

Loggerhead turtles (Caretta caretta), being ectothermic organisms, could be especially susceptible to climate change effects, and may exhibit climate‐related variation in their reproductive behaviours such as phenology, annual nest numbers, clutch size, hatching success, incubation period and sex ratio. This study investigated the reproductive phenology and outputs of loggerhead turtles and their relationships with climatic variables over a 5‐year period (2019–2023) at Patara Beach, Türkiye. We found significant fluctuations in atmospheric temperature, sea surface temperature and relative humidity, and that female turtle emergences on Patara Beach could temporarily adjust their phenology in response to these minor environmental changes. We highlight the importance of understanding the impacts of phenological shifts on the ability to satisfy the conditions over the nesting season that determine reproductive output. Our statistical analyses also showed that increasing sea water temperatures and atmospheric temperatures, as well as decreasing precipitation and relative humidity, had direct and/or indirect effects on the nesting phenology and reproductive output of loggerhead turtles. The findings from this study indicate that atmospheric temperature significantly affected incubation period, hatching success rate, the number of dead embryos and the number of empty eggshells. Additionally, relative humidity had a significant impact on the incubation period and the number of empty eggshells. In this context, rising temperatures led to drier nest conditions, decreased incubation periods and increased nest temperatures, resulting in higher proportions of female offspring. In conclusion, there are still gaps in our understanding of the effects of climate change on the reproductive biology of loggerhead turtles, and more studies are needed at both the Mediterranean and global scales to better understand these effects. [ABSTRACT FROM AUTHOR]

Simple Summary: A comprehensive assessment of the life history parameters of the invasive Atlantic blue crab Callinectes sapidus in the Lesina Lagoon (Adriatic Sea, SE Italy) in terms of abundance, sex ratio, size–frequency distribution, morphological maturation, growth, and mortality was provided adopting a suite of analytical techniques. The results of the present study can provide a valuable knowledge basis for future comparative investigations on the fishery biology of C. sapidus in Mediterranean waters. The fishery biology of the invasive Atlantic blue crab Callinectes sapidus in the Mediterranean Sea outside the eastern sectors of the basin has been only recently investigated. Here we studied the population of C. sapidus in the Lesina Lagoon (Adriatic Sea, SE Italy). In total, 838 crabs were captured monthly between February 2021 and January 2022 using fyke nets. Abundances varied seasonally with catches per unit effort ranging between 0 and 1.76 crabs fyke nets−1 d−1 in winter and summer. Spatial abundances estimated in summer by a Carle–Strub procedure ranged between 0.06 and 0.64 crabs m−2. The sex ratio (♂/♀) was close to 1:1; males prevailed only in August and September; ovigerous females occurred from April to August. The males' size at morphological maturity was smaller than females (110.6–112.3 mm vs. 122.1–123.1 mm). Seasonal von Bertalanffy growth parameters indicated that, compared with males, females showed a shorter maximum lifespan (5 vs. 8 years), a higher growth coefficient K (0.6 vs. 0.4 y−1) and growth performance index Ф' (4.6 vs. 4.3), while maximum sizes CW∞ (237.8 vs. 232.6 mm) and seasonality indices C (0.62 vs. 0.57) were similar. Furthermore, females showed higher natural and fishing mortalities and exploitation rate. We discussed the results of the present study in the context of the available literature to provide a valuable basis for the implementation of standardized Mediterranean-scale management plans, matching exploitation of C. sapidus with sustainable conservation of coastal ecosystems. [ABSTRACT FROM AUTHOR]

This study represents a preliminary report on the occurrence of Atherina boyeri in the Porsuk Dam Lake, with a total of 420 individuals obtained from local fishermen between May and July 2023. Of these specimens, 34.76% (146 individuals) were males and 65.24% (274 individuals) were females, resulting in a calculated sex ratio (females:males) of 1:0.53. The total length of the sampled fish ranged from 6.06 to 10.84 cm and their weight ranged from 1.34 to 8.60 g. The length–weight relationship (LWR) based on total length was calculated as W = 0.00001003 L2.9359 for the female population, W = 0.00000525 L3.0665 for the male population, and W = 0.00000474 L3.0975 for the entire population. The exponential value of the total length to weight ratio, denoted as 'b', was determined as 3.0975, indicating isometric growth for the species. The mean value of the condition factor for females, males, and all individuals of A. boyeri was determined as 0.755 ± 0.085, 0.710 ± 0.076, and 0.740 ± 0.084, respectively. This study not only provides preliminary and valuable data on the presence of A. boyeri in the Porsuk Dam Lake, but also offers a significant perspective on the biodiversity of the new habitat. The findings of the study are considered to be applicable to local fisheries management authorities and decision-makers to ensure the sustainability of fishery resources and the implementation of appropriate fisheries management strategies. [ABSTRACT FROM AUTHOR]

Rhamdiopsis krugi is a highly specialized troglobitic (exclusively subterranean) catfish endemic to the phreatic water bodies of twelve caves located within two separated metasedimentary basins in the region of Chapada Diamantina, Bahia state, Brazil. This species is included in the List of Endangered Fauna of Brazil, under the Vulnerable category—VU. In general, troglobites have different strategies for searching for food and reproductive partners, as well as unique behaviors. Knowledge of the reproductive periods, as well as its feeding habits, provides fundamental data for effective protection and species conservation. Biological aspects related to feeding habits and reproduction of R. krugi were addressed across six annual cycles, considering both dry and rainy seasons. For this, stomach content analysis, using the frequency of occurrence and volumetric index methods, as well as observation of the sex ratio and stage of maturation of the gonads were carried out for 148 individuals of R. krugi sampled in eight caves in Chapada Diamantina. Stomach volumes correlated with reproduction aspects across the dry and rainy seasons. These populations showed opportunistic carnivorous feeding habits, consuming both autochthonous and allochthonous items, with a preference for foraging in submerged guano deposits, which demonstrates the catfish's strong dependence on bats. Regarding sex ratios, there was no marked seasonality; however, in rainy seasons, there was a higher proportion of maturing females, showing a reproductive tendency. During these periods, there was also a significantly higher number of stomachs with contents, showing seasonality in the diet. Specialized diet and dependence on rainy periods, especially in diet, corroborate the fragility of R. krugi, especially considering the changes in rainfall regimes in Brazil, with dry seasons exceeding eight months per year in the last ten years. [ABSTRACT FROM AUTHOR]

The world is currently facing a biodiversity crisis and for many species, this is exacerbated by historic exploitation. Monitoring programs provide an integral tool to understand changes in abundance and the impact of threats informing conservation actions. However, measures of absolute abundance for management can be misleading, particularly when there is a biased sex ratio. Here we recommend focusing on the rate‐limiting cohort for management actions using the case of North Atlantic right whales. The North Atlantic right whale has a male‐biased sex ratio, with reproductively active females making up less than a fifth of the species. We highlight the importance of understanding and incorporating reproductive potential into management actions to provide species with the best chance of recovery. [ABSTRACT FROM AUTHOR]

Over nearly two decades, I observed and amassed a capture-mark-recapture study to estimate maximum natural lifespan and lifetime distance moved in a population of Common Side-blotched Lizards (Uta stansburiana). The focal population, near the high-latitude margin of their geographic distribution (43.4 °N), was characterized by reduced abundance and diversity of predators. During 12 study years between 2004 and 2017, I marked 5,298 individual animals and annually attempted to recapture the same lizards. Of these, 2,989 were determined to be one year old at the time of first capture, with 359 (12%) recaptured in at least one subsequent year. After allowing sufficient time for animals to age out of the population naturally, I estimated that the maximum lifespan for this species is at least 7 years, which is longer than previously reported. I determined that 34 (1.1%) of these lizards survived to be at least four years of age, potentially representing a significant demographic influence for populations at higher latitudes. Moreover, I detected a significant male-bias in the sex ratio of survivors by age two. Using GPS coordinates for each annual capture, I determined that males and females did not differ in movement distances from their initial capture location as adults. Rather, individuals generally moved very little over the course of their adult lifetimes (average between first and last coordinates = 27.9 m; median = 14.4 m). Long, sedentary lives may be the norm, rather than the exception, in rangeedge populations of lizards with less abundant predators. [ABSTRACT FROM AUTHOR]

S. sphyraena is a widely distributed species with low commercial value and no sufficient scientific knowledge of its biology. In the present study, the age, growth, weight–length relationship, otolith morphometry, and reproduction of the species were investigated in the Eastern Ionian Sea for the first time. The von Bertalanffy growth function parameters were L∞ = 63.65 cm, k = 0.14 year−1 and t0 = −2.01 years and Φ′ = 2.75. The negative allometric growth in weight was found. Slope b of the weight–length relationship was 2.634. For the otolith moprhometry, the variables radius, length, width, area, perimeter, roundness, circularity, form factor, rectangularity, and ellipticity were examined, which showed that the otolith shape is elongated with an elliptical and rectangular form. Six otolith variables (radius, length, width, area, perimeter, and ellipticity) showed a significant relationship with size. The sex ratio (females/males) was 1:0.74 (no statistically significant difference from 1:1), and the spawning season extended from April to June with peak values of GSI in May for females and April for males. The results of this work improve our knowledge of the species life cycle and provide basic information for species stock identification and fisheries management. [ABSTRACT FROM AUTHOR]

Given the important ecological role played by social wasps and the fact that parasitism is the main cause of mortality in the early stages of development of these wasps, it is of paramount importance to understand the ecological relationships between hosts and parasitoids. Therefore, the present study presents information on the sex ratio of Elasmus polistis for four Neotropical social wasps hosts, an update list of sixteen known host species of this parasitoid with geographic distribution. These results contributed for to two new Polistes species hosts, and for the first time in colonies of the genus Mischocyttarus. [ABSTRACT FROM AUTHOR]

The offspring sex ratio of the Demoiselle crane (Anthropoides virgo Linneaus, 1758) was analyzed in two remote breeding groups of the European (Republic of Kalmykia) and Asian (Republic of Buryatia) parts of the range in 2023. Using the molecular genetic marker EE0.6, the sex was determined in 46 chicks (24 males and 22 females) from 30 broods. In the total sample, the deviations from equal proportion of females and males were not significant (0.521, P = 0.092). The sex ratio in each of the studied breeding groups also did not statistically differ from parity, although males (0.650, P = 0.523) prevailed in two-chick broods and in general in the offspring of the Demoiselle crane in Kalmykia (0.423, P = 0.781), while females prevailed in two-chick broods and in general in the offspring of the Demoiselle crane in Buryatia (0.423, P = 0.781). The obtained data support the strategy of reproduction of parity number of both sexes in the Demoiselle crane and may indirectly indicate that in this species the energy cost on raising males and females is equal, and the pressure of environmental conditions is not so strong to cause bias of the existing balance towards either sex. [ABSTRACT FROM AUTHOR]

An investigation of aspects of the reproductive biology of the common octopus Octopus vulgaris caught in the Atlantic waters of southern Morocco was undertaken in 2020. The study focused on the demographic structure and sexual maturity of O. vulgaris by sampling landings of the coastal trawl and artisanal fleets active in the study area between Sidi El Ghazi and Cap Blanc. The artisanal fleet exploited mainly medium-sized individuals (on the commercial grade 'Mitsubishi' scale) as T5 (>1.2–1.5 kg) to T3 (>2.0–3.0 kg), whereas coastal trawlers tended to exploit smaller individuals in size classes T8 (>0.3–0.5 kg) to T6 (>0.8–0.2 kg). The sex ratio of the catches was significantly different between the coastal trawl and artisanal fleets (p = 0.043), being in favour of males in the landings of coastal trawlers (1.14:1 M:F) and in favour of females in the artisanal fleet (0.91:1 M:F). Size at first maturity of this species in the study area, denoted by dorsal length of the mantle and weight, respectively, was 14.98 cm and 370.56 g for males, and 15.75 cm and 563.08 g for females. [ABSTRACT FROM AUTHOR]

Sex-ratio meiotic drivers are selfish genes or gene complexes that bias the transmission of sex chromosomes resulting in skewed sex ratios. Existing theoretical models have suggested the maintenance of a four-chromosome equilibrium (with driving and standard X and suppressing and susceptible Y) in a cyclic dynamic, but studies of natural populations have failed to capture this pattern. Although there are several plausible explanations for this lack of cycling, interference from autosomal suppressors has not been studied using a theoretical population genetic framework even though autosomal suppressors and Y-linked suppressors coexist in natural populations of some species. In this study, we use a simulation-based approach to investigate the influence of autosomal suppressors on the cycling of sex chromosomes. Our findings demonstrate that the presence of an autosomal suppressor can hinder the invasion of a Y-linked suppressor under some parameter space, thereby impeding the cyclic dynamics, or even the invasion of Y-linked suppression. Even when a Y-linked suppressor invades, the presence of an autosomal suppressor can prevent cycling. Our study demonstrates the potential role of autosomal suppressors in preventing sex chromosome cycling and provides insights into the conditions and consequences of maintaining both Y-linked and autosomal suppressors. [ABSTRACT FROM AUTHOR]

The results of studies of the impact of 2,2',5,5'-tetrachlorobiphenyl (PCB 52) on the body of the freshwater fish Danio rerio(Hamilton, 1822) in the period preceding spawning are presented. During this experiment, it is established that exposure to PCB 52 for both males and females leads to the increased mortality of offspring in the early stages of development. It is noticeably predominant in groups in which only male parents are exposed to harmful effects. Shifts in the sex ratio in groups among the surviving offspring with a predominance of females compared to the control also turn out to be significant. This effect is more pronounced in offspring groups in which only female parents are exposed. After measuring PCB 52 concentrations in parent animals using gas chromatography–mass spectrometry, it is found that the PCB 52 content in females is almost twice as high as in males. It is concluded that a decreased viability and an imbalance in the sex ratio in the offspring has a pronounced sex dependence when exposed to PCB 52 on the body of the animal parents. [ABSTRACT FROM AUTHOR]

Despite the overall decline in smoking prevalence, the self-reported smoking prevalence among women in their 20s and 30s has increased in recent years. Focus on gender social norms as one factor determining women's smoking behavior, we examine how gender social norms formed in adolescence influence women's smoking decisions in adulthood. Using the sex ratio at birth in women's growth regions as a proxy for gender social norms, we find that when the sex ratio at birth for fourth or higher-order children in the growth region decreases by one standard deviation, women at age 19-39 statistically significantly increase the probability of smoking by a 0.12 standard deviation. Subsample analyses reveal that the influence of gender social norms is particularly pronounced among unmarried women. These findings suggest that, along with the increase in the share of unmarried women, the changing gender social norms may partially explain the recent increase in smoking prevalence among Korean young women, independent of public health policy interventions. [ABSTRACT FROM AUTHOR]

In order to determine some population parameters of whiting in the Black Sea Region of Türkiye, a study was carried out between October 2018 and September 2019 on the coasts of Ordu-Samsun. Totally, 1202 whiting fish measured, which exhibited a length between 10.3 cm and 23.8 cm (av. 15.69±0.053 cm). Their weight ranged between 7.72 g and 104.69 g. The mean weight was 30.77±0.357 g. The lengthweight relationship was W=0.0045L3.1868. The sex ratio (female/male) was 2.16:1. The maximum age was seven years for females and six years for males. The growth parameters were L8=37.25 cm, K=0.089, t0=-3.955, W8=86.99 g and Ø'=2.09. Monthly variations in the gonadosomatic index (GSI) showed that spawning of whiting continued from November to May. The reproduction, growth and condition trends are related with the changes in the species growth during the year. [ABSTRACT FROM AUTHOR]

Gender Inequality in India varies from one region to another due to various socio-economic, cultural, political and economic factors which provide it a geographical dimension. Current Indian literature on this dimension has some major gaps: (1) a comprehensive inter-dependence analysis of the latest gender inequality indicator data (after 2016) is lacking; (2) in conventional studies, inclusive analysis of indicators like child sex ratio, literacy rate and educational attainment, life expectancy, political and workforce participation is insufficient; and (3) an elaborate state/union territory (UT)-wise study that considers all indicators mentioned in the previous point is inadequate. Further, most of the studies deal with variables of gender inequality separately. The present study aims to bridge these gaps by presenting a detailed state/UT-wise analysis of various indicators of gender inequality, including child sex ratio, life expectancy, literacy and attainment of education and participation in the workforce and politics. Data for these analyses are obtained from published secondary sources. Additionally, the relationship among the explored indicators for states/UTs has been examined through multiple correlations. Overall, the present study suggests that we must devise state/UT-specific policies to achieve women empowerment and gender parity because regionally varying socioeconomic, health-related and politico-cultural factors affect the state/UT-wise gender inequality indicators and their interdependence. [ABSTRACT FROM AUTHOR]

The present study aimed to evaluate the effect of different compositions of poultry-based artificial diets on the biological and morphometric parameters of the almond moth, Ephestia cautella. Three artificial diets (ADs) were prepared, where the complete diet (AD1) consisted of a bird diet, poultry feed, brown wheat flour, glycerin, and brewer's yeast. The other two tested diets were poultry-feed-deficient (AD2) and brewer's yeast-deficient (AD3—control). The tested parameters were differences in the length and weight of eggs, larvae, and pupae, larval developmental duration, adult reproductive period, fecundity, and fertility. The results showed significant differences in larval developmental period, female longevity, life span, reproductive parameters, and morphometric measurements among the tested diets. The life span was distinctly longer (40.38 ± 0.81 days) when the larvae were reared on a poultry feed-deficient diet (AD2), while a shorter lifespan (29.93 ± 0.33 and 32.17 ± 0.61 days) was recorded when larvae were reared on a complete diet (AD1) and brewer's yeast-deficient diet (AD3), respectively. The complete diet (AD1), composed of bird diet, poultry feed, brown wheat flour, glycerin, and brewer's yeast with (2:2:2:1:1) ratios, resulted in the shortest larval and pupal duration and average life span, as well as the highest fertility percentage. The highest fecundity (eggs/female: 366.77 ± 9.61) was recorded on AD3, while fertility reached almost 100% on AD1. The sex ratio was recorded as equal for both diets AD1 and AD3, while a male-biased sex ratio was recorded for AD2. Similarly, the morphometric data showed increased weight and sizes of eggs, larvae, and pupae when provided with complete (AD1) and brewer's yeast-deficient diets (AD3). The results signified the importance of poultry feed and brewer's yeast in AD1 for the mass rearing of E. cautella. [ABSTRACT FROM AUTHOR]

We examine whether religion influences sex-selection behavior under a persistent son preference. Specifically, we investigate whether religion promotes a different sex ratio among children under 5 years of age and whether religiosity has externalities on secular households, using whole-population census data and religious establishments in Vietnam. The results show that the ratio of boys is lower among religious households in both commune fixed effects and the instrumental variable (IV) approach. Furthermore, using the 1955–1974 North–South Vietnam division that reallocated religious communities for another commune-level IV, we find that a higher pious follower ratio leads to a lower ratio of boys in the secular population. [ABSTRACT FROM AUTHOR]

Boron is primarily used in industrial applications, with recent interest revolving around its effects on metabolism. In this study, we administered boric acid (BA), which has positive effects on reproduction, in conjunction with feed supplementation to serve as a model for experimental animal development and breeding. The pregnancy performance, offspring development, and biochemical effects of mice given feed supplemented with BA at concentrations of 0 (control group), 250, and 500 ppm (BA groups) were investigated. A total of 18 female Balb-C mice were utilized for pregnancy. The mice were given the BA-supplemented feed during a period encompassing three weeks of pregnancy and three weeks of lactation. The numbers and weights of offspring born in cages on days 19–21 were determined. Blood and tissue samples were collected from the offspring during the third week postnatal, and the malondialdehyde (MDA) and total antioxidant and oxidant status (TAS, TOS, and OSI) levels were determined. A significant increase in female offspring was observed in the groups born to mice fed with BA compared to the control group. Positive development in organ weights was observed in the 250-ppm BA group. The 250-ppm group exhibited a significant increase in TAS compared to the control group, while TOS and MDA levels showed a decrease. Also, the levels of BA groups were found to decrease in both the OSI index serum and organ samples compared to the control group. Thus, the use of 250-ppm BA demonstrated positive effects on female offspring production, organ development, and antioxidant levels. [ABSTRACT FROM AUTHOR]