Male Mating Research Articles

Brood success of sex-role-reversed pheasant-tailed jacanas: the effects of social polyandry, seasonality, and male mating order.

Multiple mating by avian females may increase hatching and overall brood success; however, reproductive effort and parental investment are costly, and females may be gradually depleted, with lowered outputs over time. Thus, males in social polyandry systems may differ greatly in their reproductive gains. In the present study, we investigated the reproductive outputs of social polyandrous and sex-role-reversed pheasant-tailed jacanas, Hydrophasianus chirurgus, to assess the effects of polyandry, seasonality, and male mating order on breeding success. Female jacanas produced multiple clutches, either by leaving two or more clutches with an individual male (22%), or by mating with two or more males (78%). The polyandrous females laid both the first and second clutches earlier and showed a breeding period more than twice as long as that of monandrous females. Both polyandry and seasonality affected the fate of a clutch, where clutches from polyandrous females and the early season had higher hatching and brood success rates, but the number of polyandrous females declined over the season. Polyandrous females not only laid more clutches and eggs, and gained more hatchlings and fledglings, but also achieved higher per-clutch outputs and hatching rates than monandrous females. In polyandry groups, males gained higher total hatchlings and fledglings, although not total clutches or eggs, than males in monandry or bi-andry groups. Moreover, males in polyandry groups achieved higher hatchlings and fledglings per clutch and higher hatching and brood success rates. In polyandry groups, the first-mating males obtained more clutches, eggs, and hatchlings; however, they did not have higher success rates, nor total fledglings and per-clutch outputs, than males who mated later. Overall, the results indicate a selective advantage of polyandry for the jacanas studied, particularly in the early breeding season. This advantage, however, differs both between the sexes and intra-sexually, suggesting strong connections with certain ecological/environmental conditions in addition to the jacanas' own quality.

The availability of male mates affects the social mating strategies of a predominantly socially monogamous passerine

The availability of male mates affects the social mating strategies of a predominantly socially monogamous passerine

Genetic parameters for cloacal gland, sexual maturity, reproductive organs weight, and body weight in meat-type quail

Selection to increase body weight in poultry can hamper reproduction traits and compromise production efficiency. Thus, attention to reproduction traits is essential to improving the sustainability of breeding programs. Data from a domestic quail breeding program for meat production were used to estimate genetic parameters. We analyzed five traits: 4-week body weight, age at sexual maturity for males and females, cloacal gland area, female, and male reproductive organs weights. A multi-trait mixed model analysis with fixed effects of generation/hatch was performed, assuming environmental covariance equals zero for sex-limited traits. Heritability estimates range from low to moderate for male sexual maturity and cloacal gland area, and high for other traits. Intersexual genetic correlation for age at sexual maturity is positive, which can lead to correlated responses in the other sex. Reproductive organs weights are genetically correlated with body weight, but not significantly between sexes and nor with sexual maturity. Genetic correlations for the cloacal gland area were positive with body weight and negative with age at sexual maturity of males and females, demonstrating a potential use of this trait for selection with favorable outcomes in reproduction. The use of the cloacal gland area can be used in the same way as the scrotal circumference in mammals, improving female reproduction traits by selecting a trait recorded in males.

Consumption of β-Caryophyllene Increases the Mating Success of Bactrocera zonata Males (Diptera: Tephritidae).

The peach fruit fly, Bactrocera zonata (Saunders) (Diptera: Tephritidae), is an economically important polyphagous quarantine pest of horticultural crops endemic to South and Southeast Asia. Methyl eugenol (ME), a naturally occurring phenylpropanoid, is a male attractant used to lure and (when mixed with an insecticide) annihilate the males from the wild population, a method of pest control termed the male annihilation technique (MAT). ME is reported to enhance the mating success of sterile males of Bactrocera spp., which is critical for enhancing the effectiveness of the sterile insect technique (SIT). The suppressed response of ME-treated males to ME-baited traps/devices allows the simultaneous application of the MAT and SIT, increasing the efficiency of area-wide integrated pest management (AW-IPM) programs. However, ME treatment in sterile males in SIT facilities is logistically difficult. β-caryophyllene (BCP) is a widely occurring, safer plant compound and is considered suitable for treating males in SIT facilities. Here, we demonstrate that BCP feeding enhanced B. zonata male mating success to the same extent as ME feeding. Feeding on BCP suppressed the male's subsequent attraction to ME-baited traps, but not to the same degree as feeding on ME. The results are discussed and BCP is suggested as an alternative to ME for the concurrent use of the MAT and SIT.

IVF exposure induced intergenerational effects on metabolic phenotype in mice

Research questionWhat is the potential transmission of metabolic phenotype from IVF offspring to the subsequent generation? DesignAn IVF mouse model was established. The F1 generation mice were produced though IVF or natural mating and the F2 generation was obtained through the mating of F1 generation males with normal females. Their metabolic phenotype, including systemic and hepatic glucolipid metabolism, was examined. ResultsIt was found that IVF F1 males exhibited metabolic changes. Compared with the control group, the IVF F1 generation showed increased body weight, elevated fasting glucose and insulin, and increased serum triglyceride concentrations. IVF F1 mice also showed an increased expression of hepatic lipogenesis and autophagy genes. Moreover, IVF F1 males transmitted some metabolic changes to their own male progeny (IVF F2) in the absence of a dietary challenge. IVF F2 mice had increased peri-epididymal and subcutaneous fat and decreased insulin sensitivity. Under the ‘second hit’ of a high-fat diet, IVF F2 mice further showed increased hepatic lipid deposition with unaltered autophagy levels. ConclusionThis research demonstrates the impact of IVF on hepatic glucose–lipid metabolism in two successive generations of offspring, highlighting the need for additional investigation. Enhanced understanding of the mechanisms underlying the transmission of multigenerational effects induced by IVF could potentially lead to the advancement of therapeutic interventions for individuals experiencing infertility.

Identification and Functional Analysis of the fruitless Gene in a Hemimetabolous Insect, Nilaparvata lugens.

The fruitless (fru) gene functions as a crucial "tuner" in male insect courtship behavior through distinct expression patterns. In Nilaparvata lugens, our previous research showed doublesex (dsx) influencing male courtship songs, causing mating failures with virgin females. However, the impact of fru on N. lugens mating remains unexplored. In this study, the fru homolog (Nlfru) in N. lugens yielded four spliceosomes: Nlfru-374-a/b, Nlfru-377, and Nlfru-433, encoding proteins of 374aa, 377aa, and 433aa, respectively. Notably, only Nlfru-374b exhibited male bias, while the others were non-sex-specific. All NlFRU proteins featured the BTB conserved domain, with NlFRU-374 and NlFRU-377 possessing the ZnF domain with different sequences. RNAi-mediated Nlfru or its isoforms' knockdown in nymph stages blocked wing-flapping behavior in mating males, while embryonic knockdown via maternal RNAi resulted in over 80% of males losing wing-flapping ability, and female receptivity was reduced. Nlfru expression was Nldsx-regulated, and yet courtship signals and mating success were unaffected. Remarkably, RNAi-mediated Nlfru knockdown up-regulated the expression of flightin in macropterous males, which regulated muscle stiffness and delayed force response, suggesting Nlfru's involvement in muscle development regulation. Collectively, our results indicate that Nlfru functions in N. lugens exhibit a combination of conservation and species specificity, contributing insights into fru evolution, particularly in Hemiptera species.

Tanner crab at southwestern Kamchatka: fishing, stock condition and specifics of the assessment

Results of the current stage of research on tanner crab at the southwestern coast of Kamchatka, harvested in the Kamchatka-Kuril fishing subzone are presented. The stock dynamics since 2001 is analyzed, with special attention to its assessing and forecasting. Features of the crab biology associated with terminal molting are described. The algorithm for separation of the tanner crab recruits into morphometrically mature and immature males is developed that allows to calculate probability for a particular size group of morphometrically immature males to undergo the terminal molt and join to the commercial stock. This algorithm is applied for the data collected at southwestern Kamchatka since 2010. Two peaks in total male abundance of tanner crab were observed in 2005–2006 and 2020–2022. Landing of this species was banned in the Kamchatka-Kuril fishing subzone in 2019–2020, as the result of the local population abundance drop in the previous two years, but was resumed in 2021 after its full restoration. Possible reasons for underestimation of the crab recruitment are discussed, related both with features of the species biology and methodological problems. The population in the Kamchatka-Kuril fishing subzone is currently the most abundant for tanner crab, and this stock in 2020–2022 has reached the historical peak. The fishing of tanner crab in the last three years is distinguished by high catches and high rate of the total allowable catch (TAC) utilization.

Small-bodied males invest in larger testes when highly ornamented.

Sperm competition and male mating rate are two non-mutually exclusive key evolutionary pressures selecting for larger testes within and across animal taxa. A few studies have tried to test the role of mating rate in the absence of sperm competition. Under the mating rate hypothesis, particular phenotypes of a given population that are expected to gain more mates (e.g., more ornamented males) are expected to make higher investments in testes size (a proxy for sperm production). We test this prediction in Polistes simillimus, a neotropical paper wasp in which females are single mated (no sperm competition) and males can mate with multiple partners. Testes size was predicted by body size (positive association), sexual ornamentation (negative association), and their interaction (among small males, testes size was positively related to ornamentation, but the opposite pattern was observed among large males). We propose that small-bodied well-ornamented males may face the highest risk of sperm depletion. Small-bodied males make relatively higher investment in testes size when highly ornamented. This strategy might be less profitable to large males, as they have overall larger testes. Our results provide strong evidence for the mating rate hypothesis.

Sexual Selection And Species Recognition Promote Complex Male Courtship Displays In Ungulates

Abstract Identifying the evolutionary drivers of sexual signal complexity is a key challenge in the study of animal communication. Among mammals, male bovids and cervids often perform elaborate gestural displays during courtship, consisting of ritualized movements of various parts of the body but the causes underlying interspecific variation in complexity of such displays remain poorly understood. Here we apply the comparative method to investigate which factors may have either promoted or constrained gestural repertoire size. We found that sexual selection was a strong predictor of gestural display complexity in male bovids and cervids. Repertoire size was positively correlated with breeding group size, an indicator of the intensity of sexual selection on males. Moreover, repertoires were larger in species adopting non-territorial and lek breeding mating systems than in species adopting resource-defence territoriality, a finding that can be explained by more emphasis on direct benefits than indirect benefits in resource-defence systems, where male mating success may also be less skewed due to difficulty in monopolising mates. The results also indicate that gestural repertoire size was positively correlated with the number of closely-related species occurring in sympatry. This is consistent with display complexity being selected to facilitate species recognition during courtship and thereby avoid interspecific hybridization. At the same time, repertoire size was negatively associated with male body mass, possibly due to the energetic and mechanical constraints imposed on movements in very large species. By contrast, we found no evidence that the habitat drives selection for complex gestural courtship displays.

Paternity bias and cryptic female choice in chickens

Sperm competition and cryptic female choice (CFC) are two significant mechanisms of postcopulatory sexual selection that greatly impact fertilization success in various species. Despite extensive research has conducted on sperm competition and the evolution of sperm traits in internal fertilizers, our understanding of the female preferences in selecting sperm is still limited. Here, we aimed to investigate the characteristics of CFC in chickens by utilizing artificial insemination with mixed semen to control for variations in male fertilization success caused by female perception of male quality and mating order. Our results revealed that the offspring from multiple-mated females exhibited mixed paternity. Although the males had an equal number of viable sperm, one male consistently exhibited a 15% higher success rate on average, regardless of whether the insemination was performed with fresh or diluted semen. This result suggested that this male demonstrates superior performance in sperm competition, and exhibited a potential advantage in fertilization success. While the dominant male generally made a greater genetic contribution to most offspring, the degree of this advantage varied greatly, ranging from 11.11% to 75.00%. Furthermore, our study provided evidence of female preferences influenced the precedence of sperm from certain males over others. Interestingly, this bias is not consistently observed among all individuals, as offspring derived from some females were predominantly sired by an overall disadvantaged male while others were predominantly by a different disadvantaged male. Overall, these results underscored the complex processes involved in sperm selection and emphasized the importance of females in sexual selection theory.

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.

Gonadal transcriptome analysis of genes related to sex differentiation and sex development in the Pomacea canaliculata

As an invasive alien animal, Pomacea canaliculata poses a great danger to the ecology and human beings. Recently, there has been a gradual shift towards bio-friendly control. Based on the development of RNA interference and CRISPR technology as molecular regulatory techniques for pest control, it was determined if the knockout of genes related to sex differentiation in P. canaliculata could induce sterility, thereby helping in population control. However, the knowledge of sex differentiation- and development-related genes in P. canaliculata is currently lacking. Here, transcriptomic approaches were used to study the genes expressed in the two genders of P. canaliculata at various developmental stages. Gonad transcriptomes of immature or mature males and females were compared, revealing 12,063 genes with sex-specific expression, of which 6066 were male- and 5997 were female-specific. Among the latter, 581 and 235 genes were up-regulated in immature and mature females, respectively. The sex-specific expressed genes identified included GnRHR2 and TSSK3 in males and ZAR1 and WNT4 in females. Of the genes, six were involved in reproduction: CCNBLIP1, MND1, DMC1, DLC1, MRE11, and E(sev)2B. Compared to immature snail gonads, the expression of HSP90 and CDK1 was markedly reduced in gonadal. It was hypothesized that the two were associated with the development of females. These findings provided new insights into crucial genetic information on sex differentiation and development in P. canaliculata. Additionally, some candidate genes were explored, which can contribute to future studies on controlling P. canaliculata using molecular regulatory techniques.

Male mating season range expansion results from an increase in scale of daily movements for a polygynous-promiscuous bird.

Males of species with promiscuous mating systems are commonly observed to use larger ranges during the mating season relative to non-mating seasons, which is often attributed to a change in movements related to reproductive activities. However, few studies link seasonal range sizes to variation in daily space use patterns to provide insight into the behavioral mechanisms underlying mating season range expansion. We studied 20 GPS-tagged male wild turkeys (Meleagris gallopavo), a large upland gamebird, during the mating and summer non-mating seasons to test the hypothesis that larger mating season ranges resulted from male wild turkeys expanding the scale of daily movement activities to locate and court females. We delineated mating and non-mating seasons based on intensity of gobbling, a vocalization tied to courtship behavior, recorded by autonomous recording units distributed across the study area. Mating season ranges were significantly larger than non-mating season ranges. Daily ranges were larger in the mating season, as were distances between roost sites used on consecutive nights. Variance in daily range size was greater in the mating season, but low temporal autocorrelation suggested considerable daily variability in both seasons. We found no evidence that male wild turkeys changed how they distributed daily movements within seasonal ranges, or differences in habitat use, suggesting larger mating season ranges result from male wild turkeys increasing the scale of their daily movements, rather than a systematic shift to a nomadic movement strategy. Likely, the distribution of females is more dynamic and ephemeral compared to other resources, prompting males to traverse larger daily ranges during the mating season to locate and court females. Our work illustrates the utility of using daily movement to understand the behavioral process underlying larger space use patterns.

Insights into reproductive dynamics and feeding biology of Sphyraena putnamae Jordan and Seale, 1905 exploited in the Indian EEZ

The sawtooth barracuda Sphyraena putnamae, widely distributed in the Indo-Pacific region, isone of the commercially important barracuda species exploited by trawls in the Indian EEZ.The present study examined 2,135 S. putnamae collected during 2014-2020 from differentfish landing centres along the Indian coast, to elucidate their reproductive and feedingbehaviour. The fork length of sampled females and males varied from 12.5 to 130.9 cm and16.5 to 90.0 cm respectively. Negative allometric growth was observed with a significantdifference (p<0.05) between the sexes. The observed sex ratio (Female:Male) was 1.23:1,indicating the dominance of females. Size at sexual maturity for females and males wereestimated at 55.3 and 45.4 cm fork length respectively. The higher proportion of spawningcapable individuals and higher gonadosomatic index (GSI) values in females observedduring March to May and November-December revealed the bimodal and protractedspawning nature of this species. Absolute fecundity increased with fork length and weightand varied from 70,080 to 10,18,068 oocytes with an average of 3,16,568 oocytes. Thestomach vacuity index of females and males was 49.09 and 47.92% respectively. Fifty-nineprey items were identified in the diet, with a predominance of fishes confirming S. putnamaehas a piscivorous feeding behaviour. Keywords:Management, Protracted spawners, Piscivore,Sawtooth barracuda, Sex ratio

A variance-partitioning approach for assessing mate choice and which sex controls mating behavior

Abstract Mating behavior arises from interactions between males and females. The precopulatory stage includes various male and female mating behaviors that are potentially influenced (independently or jointly) by each sex, thereby shaping the dynamics of this stage. However, limited attention has been given to determining the relative contributions of males and females to the expression of precopulatory behaviors. Here, we adopted a variance-partitioning approach to assess which sex controls each precopulatory behavior. This approach also enabled us to evaluate the existence of mate choice by assessing whether the expression of precopulatory behavior depends on the identity of the opposite-sex partner. In our study, using the bean bug Riptortus pedestris, we exposed individual males and females to different opposite-sex partners (i.e., mating assays) up to six times. During the mating assay, we measured multiple precopulatory behaviors (e.g., latency to mount, courtship rate, courtship duration, and duration of position change). Variance partitioning showed that the variation in each precopulatory behavior could be attributed solely to either sex but not to both sexes. Hence, the precopulatory stage of R. pedestris comprises a combination of male-controlled and female-controlled behaviors. We also suggested that mate choice was absent in both sexes of R. pedestris in the postmounting and precopulatory stages. Our findings highlight the importance of the variance-partitioning approach in the study of mating behavior, as it facilitates the investigation of whether mate choice occurs at specific mating stages and enhances our understanding of evolutionary dynamics during mating.

Does morphological maturity anticipate physiological maturity? The pattern of sexual maturity in males of the seabob shrimp Xiphopenaeus kroyeri (Heller, 1862)

The seabob shrimp Xiphopenaeus kroyeri (Heller, 1862) is an important fishing resource and is intensely exploited in South America. Therefore, for the correct and sustainable use of this fishing resource, it is necessary to employ multiple tools to determine the sexual maturity of this species, a key condition for the maintenance of this important economic resource. In this work, we evaluated the morphological (development of secondary sexual characteristics) and physiological (maturation of the reproductive system) sexual maturities in males of X. kroyeri, through the macroscopic and microscopic description of the testes, vasa deferentia and petasma from the juvenile stage to the adult stage. The male reproductive system of seabob shrimp is a paired organ with testes connected to a vasa deferentia, which is anatomically differentiated into three regions: proximal (PVD) (subdivided into anterior, or PVDa, and posterior, or PVDp), medial (MVD) and distal (DVD), the latter region being associated with the terminal ampulla. The morphological maturity of males preceded physiological maturity, meaning the petasma must be formed for the production of seminal fluid and the formation of spermatozoa contained in spermatophores to occur. Petasma formation occurred in the size class 12 ┤13 mm CL, while the production of spermatozoa and spermatophores occurred from 14.1 mm CL. These spermatophores are completely formed in the PVDp and are glycoproteic. Spermatophores are stored in the simple tube of the MVD and DVD. In the DVD, there is an accessory gland forming the ampulla, which produces part of the seminal fluid. The deposition of spermatophores occurs internally in the female’s thelycum with the aid of the petasma, which deposits the seminal fluid in the seminal receptacles or spermathecae. At the end of this process, the thelycum is sealed by a secretion from the accessory gland in the male’s ampulla, forming a sperm plug. Based on the results obtained here, we recommend that only physiologically mature males of X. kroyeri (> 14.1 mm CL) should be exploited by artisanal fisheries and that macroscopic inspection of the ampulla to determine physiological maturity in this species should be avoided, as this region of the DVD has the accessory gland as its main part, a structure responsible for forming the sperm plug, which does not contain spermatozoa or participate in the formation of spermatophores.

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.

Two sex pheromone receptors for sexual communication in the American cockroach.

Volatile sex pheromones are vital for sexual communication between males and females. Females of the American cockroach, Periplaneta americana, produce and emit two sex pheromone components, periplanone-A (PA) and periplanone-B (PB). Although PB is the major sex attractant and can attract males, how it interacts with PA in regulating sexual behaviors is still unknown. In this study, we found that in male cockroaches, PA counteracted PB attraction. We identified two odorant receptors (ORs), OR53 and OR100, as PB/PA and PA receptors, respectively. OR53 and OR100 were predominantly expressed in the antennae of sexually mature males, and their expression levels were regulated by the sex differentiation pathway and nutrition-responsive signals. Cellular localization of OR53 and OR100 in male antennae further revealed that two types of sensilla coordinate a complex two-pheromone-two-receptor pathway in regulating cockroach sexual behaviors. These findings indicate distinct functions of the two sex pheromone components, identify their receptors and possible regulatory mechanisms underlying the male-specific and age-dependent sexual behaviors, and can guide novel strategies for pest management.

Cre-LoxP and tamoxifen-induced deletion of ovarian quiescin sulfhydryl oxidase 2 showed disruption of ovulatory activity in mice

BackgroundQuiescin sulfhydryl oxidase 2 (QSOX2) is a flavin adenine dinucleotide-dependent sulfhydryl oxidase that is known to be involved in protein folding, cell growth regulation, and redox state modification through oxidative activities. Earlier studies demonstrated the tissue and cellular localization of QSOX2 in the male reproductive tract, as well as the highly-regulated mechanism of QSOX2 protein synthesis and expression through the coordinated action of testosterone and epididymal-enriched amino acid, glutamate. However, the presence and the functions of QSOX2 in female reproduction are unknown. In this study, we applied the Cre-loxP gene manipulation system to generate the heterozygous and homozygous Qsox2 knockout mice and examined its effects on ovarian function.ResultsWe demonstrated that QSOX2 was detected in the follicle-supporting cells (granulosa and cumulus cells) of ovarian follicles of all stages but was absent in the corpus luteum, suggesting its supportive role in folliculogenesis. In comparison with reproductive organogenesis in wild-type mice, there was no difference in testicular and epididymal structure in male Qsox2 knockout; however, Qsox2 knockout disrupted the regular ovulation process in female mice as a drastic decrease in the formation of the corpus luteum was detected, and no pregnancy was achieved when mating males with homozygous Qsox2 knockout females. RNAseq analyses further revealed that Qsox2 knockout altered critical signaling pathways and genes that are responsible for maintaining ovarian functions.ConclusionOur data demonstrated for the first time that Qsox2 is critical for ovarian function in mice.

Male mating success in the Omei treefrog (Rhacophorus omeimontis): the influence of body size and age

In anuran mate choice, advantaged males are generally known to be larger or older individuals. To test whether male mating success in the foam-nesting treefrog Rhacophorus omeimontis, a species distributed in western China, correlated with body size and age, we analysed differences in body size and age among three types of males. Males were classified as mated, joining or unmated at the time of sampling with joining males being additional males joining pairs in amplexus. Our results showed that there were no significant differences in body size among the three types of males. However, age was an important factor, with mated males being significantly older than joining and unmated males, which indicated that older individuals tended to have greater mating success than younger frogs.