Number Of Matings Research Articles

Molecular Evaluation of the Mating Dynamics of Snow Crab (Chionoecetes opilio) in the Eastern Bering Sea

ABSTRACTSnow crab (Chionoecetes opilio) in the eastern Bering Sea (EBS) supports a valuable crab fishery that harvests large males. To better understand the potential impact of the presence of snow‐Tanner hybrids (C. opilio × C. bairdi) on snow crab mating dynamics, the maternal lineage of hybrids was evaluated using single nucleotide polymorphisms (SNPs). Contrary to results from a previous study that indicated hybrids result only from crosses between Tanner crab (C. bairdi) males and snow crab females, results from this study showed hybrids result from bidirectional parental crosses. SNP and microsatellite markers were used to evaluate the species and number of males detected as mates in female sperm reserves acquired during mating and as sires among embryos in brooded clutches. The incidence of interspecies mating between female snow crab and Tanner crab or hybrid males was low (2%), suggesting interspecies mating is not currently a pressing fishery management concern. Most females had stored sperm from either a single mate (59%) or two mates (32%), which reflects fewer mates than observed for other snow crab populations. Few females were observed with either no stored sperm (5%) or sperm from three to four mates (4%). Single (82%) or dual (18%) paternity was found among embryos in brooded clutches. Sperm from some mates appeared to be fully utilized for fertilization of the brooded clutch for 35% of females. In contrast to findings for other snow crab populations, no significant differences were detected in the numbers of mates or sires between primiparous and multiparous females. The low extent of polyandry observed may suggest that female snow crab in the EBS have limited mating opportunities, potentially leading to insufficient sperm reserves to fertilize subsequent clutches without remating.

Social interactions of dairy cows and their association with milk yield and somatic cell count

The social environment experienced by livestock can have implications for their health, welfare, and subsequently, their productivity. Changes in the dairy industry have led to larger herd sizes and altered management of cows, which has impacted their social environment. Studies have shown that mixing of animals can lead to social instability of groups and expansion of herds can lead to high stocking densities resulting in social stress and negative effects on production. Yet few studies have assessed the putative impact of positive cow-cow interactions, such as proximity to preferred herd mates and engaging in grooming, on milk production and udder health. To address this, we used cattle proximity as a proxy for affiliative interactions between cows in three dairy herds in south-west England over one week study periods. We created proximity networks of dairy cows and measured cow-cow associations according to milk yield, somatic cell count (SCC; an indicator of mastitis), parity (number of lactations in the cow’s lifetime), and lactation stage (grouped by days in milk for current lactation). We then assessed associations between social factors and production and health measures (milk yield and SCC). In all three herds, cows interacted more with cows in the same parity, suggesting early social bonding may be evident later in life and that grouping animals in terms of parity might encourage affiliative interactions. Cows did not associate according to milk yield, SCC, or lactation stage. There was no significant association between milk production or SCC and the total time spent in social contact with other cows, the mean time spent with the four closest herd mates, or the number of closest herd mates of the same parity. We suggest that further research on positive social environments for dairy cattle is warranted in the interests of improving welfare and enabling a more robust assessment of the putative effects on production and health parameters

Unraveling the impact of hyperleptinemia on female reproduction: insights from transgenic pig model

BackgroundInfertility is a growing global health concern affecting millions of couples worldwide. Among several factors, an extreme body weight adversely affects reproductive functions. Leptin is a well-known adipokine that serves as an endocrine signal between adiposity and fertility. However, the exact mechanisms underlying the effects of high leptin level on female reproduction remain unclear.MethodsTransgenic pigs overexpressing leptin (♀) were produced by backcrossing and screened for leptin overexpression. The growth curve, fat deposition, reproductive performance, apoptosis, serum hormones and cholesterol production, RNA sequencing, and single-nucleus RNA sequencing (snRNA-seq) of the leptin-overexpressing pigs and wild-type group were evaluated.ResultsTransgenic pigs overexpressing leptin (♀) were obtained, which exhibited significantly reduced body weight, body size, and back fat thickness. These pigs manifested a late onset of puberty (330 ± 54.3 vs. 155 ± 14.7 days), irregular estrous behavior characterized by increased inter-estrous interval (29.2 ± 0 vs. 21.3 ± 0.7 days), and more number of matings until pregnancy (at least 3 times). This reproductive impairment in leptin pigs was related to hormonal imbalances characterized by increased levels of FSH, LH, prolactin, E2, P4, and TSH, altered steroidogenesis such as increased levels of serum cholesterol esters along with steroidogenic markers (StAR, CYP19A), and ovarian dysfunctions manifested by neutrophilic infiltration and low expression of caspase-3 positive cells in the ovaries. Moreover, bulk RNA sequencing of the ovaries also revealed neutrophilic infiltration followed by upregulation of inflammation-related genes. Furthermore, snRNA-seq reflected that leptin overexpression triggered immune response, suppressed follicle development and luteinization, resulting in metabolic dysfunction and hormone imbalance in the ovary.ConclusionsLow body weight in leptin overexpressing pigs adversely affects the reproductive performance, causing delayed puberty, irregular estrous cycles, and reduced breeding efficiency. This is linked to metabolic imbalances, an increased immune response, and altered ovarian functions. This study provides a theoretical basis for the complex mechanisms underlying leptin, and infertility by employing leptin-overexpressing female pigs.

Physiological Status of Rice Leaf-Roller Cnaphalocrocis medinalis (Lepidoptera: Crambidae) Adults Trapped by Sex Pheromone and Floral Odor.

The rice leaf-roller Cnaphalocrocis medinalis is an important migratory pest of rice. We conducted a study to determine the physiological status of adults trapped by a sex pheromone and floral odor. In the immigrant group, the number of males trapped by the floral odor was greater than the number caught by sex pheromone trapping. The volume of testes was similar in the above two trapping methods but was smaller than in the sweep net method. The ovary developmental grade, mating rate, and number of matings of females caught in floral odor trap were higher than in those caught in the sweep net. In the local breeding group, the number of males trapped by sex pheromones was greater than the number trapped by the floral odor. The volume of testes was smaller in the floral odor trap compared to the pheromone trap group, with the largest in the sweep net group. The ovarian developmental grade, mating rate, and number of matings of females were significantly higher in the floral odor trap group than in the sweep net group. In the emigrant group, the adult olfactory response to the sex pheromone and floral odor was low. The volume of testes was larger in the sweep net group compared to the moths caught by floral odor trapping. The number of eggs laid by female immigrants trapped by the floral odor and sweep net was similar, while the number in the local breeding group was greater in moths caught with the sweep net in comparison with those caught by the floral odor trap. The difference in egg hatchability between the two trapping methods in both immigrants and local breedings was not significant.

Imputation accuracy and carrier frequency of deleterious recessive defects in Australian dairy cattle

Widespread genotyping has enabled the identification of putative recessive mutations that affect fertility through early embryonic fetal loss, or that compromise neonate or calf viability. The use of artificial insemination in the global dairy population can rapidly spread these harmful mutations, and testing for multiple mutations can become relatively expensive if not all tests are available on the same SNP panel. However, it is possible to provide heifer and cow predicted carrier status to farmers at no additional cost if the animals are genotyped with a standard SNP panel. Additionally, for defects where the causal mutation is unknown but a haplotype of markers has been associated with the defect, the carrier status can be predicted based on that haplotype. The aims of this study were 3-fold: (1) to determine the accuracy of imputation of putative causal mutations for recessive deleterious conditions in Australian dairy cattle, (2) to impute carrier status for known recessive deleterious conditions in all genotyped Australian Holstein, Jersey, and Red breed cows, and (3) to determine the changes in carrier frequencies across time for these recessive deleterious mutations. We used the F1 statistic, combining precision and recall, to assess the accuracy of carrier status prediction. We showed that known deleterious mutations can be accurately imputed in Australian Holstein and Jersey cattle that are not directly genotyped for the causal mutation, with F1 ranging between 0.88 and 0.99. For recessive deleterious conditions not included on the standard Australian SNP panel, carrier status could be predicted using a marker haplotype, with F1 ranging from 0.91 to 0.92. Most putative causals and haplotypes were either stable with a low carrier percentage or had a declining carrier percentage. However, several recessive mutations showed a relatively high or increasing percentage, highlighting the importance of detecting carriers to reduce the number of at-risk matings. Furthermore, the high carrier percentage of the recently identified bovine lymphocyte intestinal retention defect mutation emphasizes the importance of detection of novel mutations.

Lifetime reproductive characteristics of gray wolves

Abstract Female and male cooperative breeders can use different strategies to maximize reproduction and fitness over their lifetimes. Answering questions about fitness in cooperative breeders requires long-term studies as well as complete data on group composition and size which can be exceedingly difficult to obtain. Using a long-term genetic data set of complete group pedigrees, I asked how lifetime reproductive characteristics of female and male gray wolves (Canis lupus) differed. I predicted that genetic relatedness to helpers would be higher for females than males due to philopatric behavior of female wolves, group size would be similar between the sexes, females would inherit breeding positions from within groups more often than males due to differences in dispersal strategies between the sexes, males would have more lifetime mates and produce more young than females because of polygamy, and females would breed for more years than males due to the likelihood that females would still breed (with a new partner) after a mate died or was expelled from the group. I documented complete lifetime breeding histories for 11 male and 18 female wolves in Idaho, United States, 2008 to 2018. Genetic relatedness to helpers, group size, number of mates, pups, and years breeding did not differ between the sexes. Females, however, inherited breeding positions within groups far more often than males. Individuals who secured breeding positions generally reproduced for 2 seasons and commonly had more than 1 partner during their lifetimes if they were able to maintain their breeding position longer. Direct fitness varied greatly within female and male breeding wolves.

Impact of Natural and Mechanical Mating on Fecundity and Egg Retention in Muga Silkworm, Antheraea assamensis (Lepidoptera: Saturniidae)

Lepidopteran muga silkworm Antheraea assamensis belonging to Saturnidae is an economically important insect geographically endemic to Assam and the northeastern region of India. Like any other insect species, oviposition is one of the most vital aspects of A. assamensis as it allocates the majority of its energy during its lifecycle. Muga silkworm seed production technology has still not been studied much in detail. The demand for silkworm seeds rises during the commercial rearing season in the region, Central Silk Board has established seed production centres to cater for the demand of the sericulture industry. The number of seed cocoons processed for commercial seed production is 1.5-2.5 lakhs per annum. Muga silkworm emergence pattern is asynchronous, no. of male and female moths is not equal during operations. A. assamensis is nocturnal in habit, and emergence and coupling take place at night. Due to the asynchronous pattern of emergence, it is quite often that female moths run out of mates in the seed production centres. Due to the depleting number of potential male mates, the mating will be done mechanically by putting male female moths in a bamboo box to save the time and energy of silk moths. So, an experiment was conducted to study the difference in fecundity between naturally mated and mechanically mated muga silkworms and its impact on mating duration at Silkworm Seed Production Centre, Kaliabari, Boko, Assam during commercial crop (April-May & Oct-Nov) of 2023. The results of the study showed that maximum fecundity was observed in silkworms which are naturally mated with 214±12.08 eggs per female. Whereas, the mechanically mated muga silkworm females showed slightly less fecundity compared to naturally mated females with 203.2±12.77 eggs per female. The results on egg retention showed a clear difference with 18.6±4.77 and 16.6±8.64 eggs per female in natural and mechanical mating, respectively. The slightest reduction in fecundity and increased egg retention in female moths might be due to the impact of mechanical mating on mating duration which reported only 5.5±1.29 hrs, whereas natural mating facilitated a higher mating duration with 8.2±1.30hrs, respectively. This study showed the significance of mating type (natural and mechanical) and its impact on fecundity and egg retention of muga silkworm.

Mating competition among females: testing the distinction between natural and sexual selection in an insect.

In species where females compete for mates, the male often provides the female with resources in addition to gametes. A recently suggested definition of sexual selection proposed that if females only benefit from additional resources that come with each mating and not additional gametes, female intrasexual competition for mating opportunities would result in natural selection rather than sexual selection. The nuptial gift-giving bushcricket Kawanaphila nartee has dynamic sex roles and has been a textbook example of sexual selection acting on females via mating competition. We investigated whether females of this species gain fitness benefits from nuptial gifts, additional ejaculates or both by controlling the number of matings and whether the female was allowed to consume the nutritious gift (spermatophylax) at mating. We found that egg production per day of life increased with the number of additional matings, both with and without spermatophylax consumption, but consuming the spermatophylax had an additional positive effect on the number of eggs. These effects were particularly strong in females with shorter lifespans. We discuss how the recently suggested definition of sexual selection applies to nuptial-feeding insects and conclude that both natural and sexual selections influence mating competition in K. nartee females.

Volatiles of essential oils and yeast derivatives influence mating behaviour of Anastrepha fraterculus males under field cage conditions

AbstractThe sterile insect technique (SIT) is used for the management of tephritid fruit fly pests. The South American fruit fly, Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae), is one potential pest to be targeted by means of SIT. The success of SIT depends, to a large extent, on the sexual performance of sterile males. Various approaches have been evaluated with the aim of improving their sexual performance. These include the exposure to plant‐derived compounds and/or the provision of protein sources in the adults' diet capable of stimulating male mating success. The present study aimed to determine whether exposure to volatiles of Citrus limon (L.) Burm. F. (Rutaceae) essential oil and limonene confers a mating advantage to A. fraterculus laboratory males fed two distinct dietary regimes when competing with wild males for wild females under field cage conditions. Dietary regimes were, one, with non‐hydrolysed brewer's yeast and sugar (1:3 ratio), and the other with brewer's yeast hydrolysate enzymatic and sugar (1:12 ratio). The effect was evaluated in four variables associated with mating success: number of copulas obtained, latency to mate, copula duration, and copula location. Exposure to volatiles did not affect the number of matings achieved, irrespective of the diet given to the males. When laboratory males were fed with brewer's yeast hydrolysate, the effect of volatile exposure was shown in latency to mate, copula duration, and copula location. When the laboratory males were fed with non‐hydrolysed brewer's yeast, the effect of volatile exposure was shown only in copula duration. Laboratory males fed brewer's yeast hydrolysate achieved the same number of matings as wild males, whereas laboratory males fed non‐hydrolysed brewer's yeast had lower performance.

Mechanisms for polyandry evolution in a complex social bee

Polyandry in social Hymenoptera is associated with reduced within-colony relatedness and increased colony-level ecologic fitness. One explanation for this sees increasing within-nest genetic diversity as a mechanism for improving group task efficiency and colony competitiveness. A queen on her mating flight captures nearly 90% of her breeding population’s allele potential by her tenth effective mating (me ~ 10 males). Under this population allele capture (PAC) model, colony fitness gains track mating number in an asymptotic manner, leveling out after about the tenth mating. A supporting theory we call the genotype composition (GC) model sees genetic novelty at mating levels higher than the me ~ 10 asymptote, the hyperpolyandry zone, resulting from unique genotype compositions whose number are potentially infinite. Colony fitness gains under the GC model will track mating number in a linear manner. We set up field colonies with Apis mellifera queens each instrumentally mated with 1, 2, 4, 8, 16, or 32 males, creating a polyandry gradient bracketing the qualitative divide of me ~ 10, measured tokens of colony level fitness, and collected observation hive data. Our results lead us to conclude that (1) ancestral colony traits fundamental to eusociality (cooperative brood care) respond to mating level changes at or below me ~ 10 in a manner consistent with the PAC model, whereas (2) more derived specialized colony phenotypes (resistance to the non-native parasite Varroa destructor) continue improving with increasing me in a manner consistent with the GC model. By either model, (3) the mechanism for increasing colony fitness is an increase in worker task specialisms and task efficiency.Significance statementPolyandry is a female’s practice of mating with many males, storing their sperm, and using it to produce genetically diverse offspring. In complex social bees, a queen captures nearly 90% of her breeding population’s diversity potential by her tenth mating; however, queens in nature routinely mate with many more than ten males. We tested two models that, together, explain how social bee colonies ecologically benefit from queen mating numbers ranging from 2 to potential infinity. A population allele capture (PAC) model focuses on colony fitness gains at mating numbers at or below 10, and we provide evidence that it was at these polyandry levels that significant gains were made in an ancestral eusocial trait, cooperative brood care. A genotype composition (GC) model focuses on colony fitness gains at higher mating numbers, and we believe these gains are centered around more recently evolved ecologic specialisms such as parasite resistance.

Reproduction mode and Strain effects on Rabbit Breeding Performances

This study was carried out to determine the impact of the mode of reproduction and the strain (male and female) of rabbits on some zootechnical and reproduction parameters. For that, monitoring was carried out in 2019 in the region of Setif (North Eastern Algeria) on a semi-intensive breeding of 25 crossbreed rabbits. The statistical analysis showed a very highly significant effect of the mode of reproduction on the number of mating per fertilizing mating (P= 0.0001) with an average of 1 ± 0 in AI (Fertility rate of 80%), while it was of 1.45 ± 0.51 in natural breeding with a fertility rate of 61%. The weight of the rabbits at weaning was higher in AI than in natural mating (587.25 ± 338.19 g vs. 575.0 ± 375.44 g, respectively). The results relating to the number of total born, born alive, weaned rabbits, the farrowing-mating interval and the farrowing-fertilizing mating interval in natural mode were respectively of (7.4 ± 3.12), (4.55 ± 3.12), (4.55 ± 3.12), (12.65 ± 2.30), (19.15 ± 3.58); and in AI: (6.90 ± 4.12), (5.75 ± 4 .12), (5.75 ± 4.12), (11.65 ± 2.05), (18.99 ± 3.2) (P>0.05). Furthermore, and regarding the strains, data revealed that the females did not have any significant effect on the variables studied. On the contrary, the male had a very highly significant effect on the number of mating per fertilizing mating (p = 0.000), while it had no impact on the other parameters (P>0.05). To conclude, the control and the management of reproduction is the key to success in rabbit breeding, thus the combination of rearing condition and genetic effects is the main tool for making rabbit farming successful.

Among-individual variation in flowering phenology affects flowering synchrony and mating opportunity.

The timing and pattern of a plant's flowering can have important consequences for reproductive success. Variation in flowering phenology may influence the number of prospective mates, the risk of mating with lower quality individuals, and the likelihood of self-pollination. Here we use a common garden experiment to explore within- and among-population variation in phenology. Our work provides new insights into how flowering phenology shapes mating opportunity and flowering synchrony in a self-compatible perennial. To quantify variation in flowering phenology we raised progeny from nine populations of Mimulus ringens in a common garden. For each individual, we measured phenological traits including age at flowering onset, daily floral display size, total flower number, and flowering synchrony with other members of the population, and related these traits to mating opportunity. We also tested how individual flowering schedules influence the magnitude of synchrony. Flowering phenology and synchrony varied substantially within and among populations. From day to day, plants often oscillated between large and small daily floral displays. Additionally, flowering schedules of individual plants strongly influenced flowering synchrony and, along with the number of flowering days, markedly affected plants' mating opportunity. Phenological traits such as flowering synchrony can affect the quantity of mating opportunities and may be important targets of natural selection. Our results highlight the need for studies that quantify flowering patterns of individuals as well as populations.

Behavioral estimates of mating success corroborate genetic evidence for pre-copulatory selection

Abstract In promiscuous species, fitness estimates obtained from genetic parentage may often reflect both pre- and post-copulatory components of sexual selection. Directly observing copulations can help isolate the role of pre-copulatory selection, but such behavioral data are difficult to obtain in the wild and may also overlook post-copulatory factors that alter the relationship between mating success and reproductive success. To overcome these limitations, we combined genetic parentage analysis with behavioral estimates of size-specific mating in a wild population of brown anole lizards (Anolis sagrei). Males of this species are twice as large as females and multiple mating among females is common, suggesting the scope for both pre- and post-copulatory processes to shape sexual selection on male body size. Our genetic estimates of reproductive success revealed strong positive directional selection for male size, which was also strongly associated with the number of mates inferred from parentage. In contrast, a male’s size was not associated with the fecundity of his mates or his competitive fertilization success. By simultaneously tracking copulations in the wild via the transfer of colored powder to females by males from different size quartiles, we independently confirmed that large males were more likely to mate than small males. We conclude that body size is primarily under pre-copulatory sexual selection in brown anoles, and that post-copulatory processes do not substantially alter the strength of this selection. Our study also illustrates the utility of combining both behavioral and genetic methods to estimate mating success to disentangle pre- and post-copulatory processes in promiscuous species.

Divorce is linked with extra‐pair paternity in a monogamous passerine

The question of why socially monogamous females engage in extra‐pair behaviour is long‐standing in evolutionary biology. Due to a lack of empirical support among passerine birds, recent work has moved away from the indirect‐benefits hypothesis to explain extra‐pair mating behaviour by females, instead favouring the hypothesis that this is the result of a pleiotropic effect. That is, a trait under strong positive selection in either or both sexes are genetically linked with another, potentially unrelated, trait. For example, genes beneficial to female fecundity (that promote within‐pair solicitation of mating from a male partner) might also lead to extra‐pair behaviour (by also promoting solicited copulations from extra‐pair males). Here, we test two predictions from this hypothesis: We test the prediction that female divorce, measured as the number of social mates within a given year, is linked with 1) the number of extra‐pair males engaged by the female and 2) the proportion of the female's offspring that are extra‐pair. Our results show that females who divorce their social partner are more likely to produce extra‐pair offspring than those who maintain social monogamy, supporting the pleiotropy hypothesis. However, those females did not also have a higher proportion of extra‐pair offspring. The number of broods initiated was also positively correlated with the number of extra‐pair males that sired a female's offspring, probably through increased opportunity for extra‐pair males to sire offspring over a longer breeding season. Our results support the intrasexual pleiotropy hypothesis as a driver of female extra‐pair behaviour.

119 Pedigree and Population-Based Genomic Inbreeding Trends Over Time in Five Commercial Swine Breeding Populations

Abstract Controlling inbreeding within a population is critical to maintain additive genetic variance and reduce negative consequences such as inbreeding depression in small, closed herds. Some breeding programs may utilize subjective standard operating procedures (SOPs) such as setting the minimum number of boars, limiting the number of matings per boar, and limiting the relationships among active boars. Software programs such as Matesel can control inbreeding within a population more precisely using evolutionary algorithms by optimizing the mating and selection process to constrain inbreeding at a given target degree or other metric specified (e.g., coancestry). The main problem has been the choice of what relationship matrix to use in constraining inbreeding in these programs. Furthermore, there are many different genomic inbreeding metrics that can be used to quantify inbreeding rates over time. The objective of the current research was to investigate the trends in the pedigree [PED, (A diagonal – 1) * 100] and two population-based genomic inbreeding metrics. One based on expected homozygosity (2pq, Ghom) and one based on drift (squared allele frequency changes, Gdrift). Data included nucleus animals born from 2017 through 2022 from five different genetic lines (lines A-E). Most parents and male selection candidates were genotyped using the commercial 50k SNP panel from GeneSeek. Pedigree was traced back at least 3 generations. A total of 80k animals were sampled from the total number of genotyped animals for computational reasons across line and birth year. Results show that in general, the maternal lines (A and B) showed the least rate of inbreeding over time (0.30 and 0.43% / year for A and B, respectively), while terminal lines were greater, especially line D (0.36 to 0.76% / year). Pedigree inbreeding in 2022 was between 1.48% (line A) to 3.80% (line D) after subtracting the average pedigree inbreeding in 2017. Population-based genomic measures of inbreeding showed a very small difference in line A (0.09%), larger Gdrift than Ghom in line B (1.37%), and larger Ghom than Gdrift in lines C, D, and E (2.87% to 4.38%). In general, the trend for PED and Gdrift was very similar for all lines, while Ghom tended to increase rapidly out of control in the three terminal lines (C-E) in later years. Future research will focus on integrating results from the diagonals of a variety of G matrices on an individual basis (e.g., VanRaden 1 and 2, runs-of-homozygosity, and a linkage-analysis matrix). Results showed the pedigree and genomic drift trends over time were similar, however, the genomic homozygosity trend was much greater in terminal lines.

Effects of Low Vitamin C Intake on Fertility Parameters and Pregnancy Outcomes in Guinea Pigs.

Identifying how specific nutrients can impact fertility, pregnancy, and neonatal outcomes will yield important insights into the biological mechanisms linking diet and reproductive health. Our study investigates how dietary vitamin C intake affects various fertility parameters and pregnancy and neonatal outcomes in the guinea pig, a natural model of vitamin C dependency. Dunkin Hartley guinea pigs were fed an optimal (900 mg/kg feed) or low (100 mg/kg feed) vitamin C diet ad libitum for at least three weeks prior to mating and throughout pregnancy. We found that animals receiving the low vitamin C diet had an increased number of unsuccessful matings, a higher incidence of foetal reabsorption, and, among pregnancies resulting in delivery at term, produced fewer offspring. Neonates from mothers on the low vitamin C diet had significantly decreased plasma vitamin C concentrations at birth and exhibited mild growth impairments in a sex-dependent manner. We conclude that a diet low of vitamin C induces a state of subfertility, reduces overall fecundity, and adversely impacts both pregnancy outcomes and growth in the offspring. Our study provides an essential foundation for future investigations to determine whether these findings translate to humans. If so, they could have important clinical implications for assisted reproductive technologies and nutritional recommendations for couples trying to conceive, pregnant women, and breastfeeding mothers.

Age trajectories in extra-pair siring success suggest an effect of maturation or early-life experience.

Across birds, male age is the most consistent predictor of extra-pair siring success, yet little is known about age effects on paternity over the lifetime of individuals. Here, we use data from a 13-year study of a population of blue tits (Cyanistes caeruleus) to investigate how extra-pair siring success changes with age within individuals. Our results indicate that extra-pair siring success does not continuously increase with male age. Instead, siring success was related to male age in a threshold fashion, whereby yearling males were less likely to gain paternity than older males. This effect was independent of the age of the social partner, but influenced by the age of the extra-pair female: success of yearlings at siring extra-pair young (EPY) with older females was even lower. Among males that sired at least one EPY, the number of extra-pair mates and the proportion of EPY sired were unrelated to male age. We found no evidence for an influence of selective disappearance on extra-pair reproduction. Senescence, if anything, only occurs at ages blue tits rarely reach. A literature review indicates that an effect of male age on extra-pair siring success may be limited to the switch from yearling to older in many species. Thus, the generally observed age effect on male extra-pair siring success may be linked to age class rather than continuous ageing. This suggests that lack of experience or not fully completed maturation are important drivers of age patterns in extra-pair paternity.

Evidence for stronger sexual selection in males than females using an adapted method of Bateman's classic study of Drosophila melanogaster.

Bateman's principles, originally a test of Darwin's theoretical ideas, has since become fundamental to sexual selection theory and vital to contextualising the role of anisogamy in sex differences of precopulatory sexual selection. Despite this, Bateman's principles have received substantial criticism, and researchers have highlighted both statistical and methodological errors, suggesting that Bateman's original experiment contains too much sampling bias for there to be any evidence of sexual selection. This study uses Bateman's original method as a template, accounting for two fundamental flaws in his original experiments, (i) viability effects and (ii) a lack of mating behaviour observation. Experimental populations of Drosophila melanogaster consisted of wild-type focal individuals and non-focal individuals established by backcrossing the brown eye (bw -) eye-colour marker - thereby avoiding viability effects. Mating assays included direct observation of mating behaviour and total number of offspring, to obtain measures of mating success, reproductive success, and standardised variance measures based on Bateman's principles. The results provide observational support for Bateman's principles, particularly that (i) males had significantly more variation in number of mates compared to females and (ii) males had significantly more individual variation in total number of offspring. We also find significantly steeper Bateman gradient for males compared to females, suggesting that sexual selection is operating more intensely in males. However, female remating was limited, providing the opportunity for future study to further explore female reproductive success in correlation with higher levels of remating.

Effects of transplantation of umbilical cord blood mononuclear cells into the scrotum on sexual function in elderly mice.

Aim: This study investigated the effect of allografting umbilical cord blood mononuclear cells (UCBMCs) into the scrotum on sexual function in male elderly mice. Methods: UCBMCs were injected once into the scrotal sheath cavity of elderly mice. Results: The transplanted UCBMCs survived in the scrotal sheath cavity for 1month. The micehad significantly increased blood testosterone concentrations, cyclic guanosine monophosphate (cGMP) levels and total nitric oxide synthase (T-NOS) activity in the corpus cavernosum and an increase inthe number of mouse matings within 30min (all p=0.000). Conclusion: Scrotum-implanted UCBMCs improve the sexual function of male elderly mice through testosterone production and the NOS/cGMP pathway, which may provide an innovative transplantation approach for thetreatment of erectile dysfunction.

Age-related mating rates among ecologically distinct lineages of bedbugs, Cimex lectularius

Understanding how many mates an animal has in its lifetime is a critical factor in sexual selection. At the same time, differences in an organism's ecology, such as the quantity and quality of food, could be reflected in different mating rates. Mating rate had a significant effect on female net fitness (i.e., lifetime offspring production), however, laboratory measurements cannot well mirror the situation in wild. The common bedbug (Cimex lectularius) is a well-established model for studying traumatic insemination and sexual conflict. The species comprises two host lineages that feed on bats (BL) or humans (HL). HL can constantly feed on human hosts throughout the year, while BLs feed only during summer months when their bat hosts occupy the roosts. Because mating in female bedbugs is closely linked to foraging, this system provides a valuable model to study mating variation in the field. We established a new method for estimating age-dependent mating rates of females in the wild by relating the fluorescent pigment accumulation in the eyes of females to the number of mating scars that manifest as melanized spots caused by the injection of sperm through the wall of the female abdomen by the male into the spermalege. In addition, using laboratory bedbugs we found that three and a half observed matings on average lead to one observed melanized mating scar. Although young BL and HL females (with low pteridine concentrations) did not differ in the number of matings, the mating rate increased with age only in HL but not in BL females. We sampled on average older BL than HL females. The lack of access to food (bat blood) during winter could explain the lack of increase in the number of scars with age in BL. In species where mating leaves visible marks, using fluorescent pigments to determine female age (applicable to most arthropods) could be an important tool to study sexual selection and mating rate in the wild. The method can help formulate sustainable and biologically lucid approaches for their control.