Male Ejaculate Research Articles

Investigation of endoplasmic reticulum stress-regulated chaperones as biomarkers in idiopathic nonobstructive azoospermia.

Azoospermia is a condition in which sperm cells are completely absent in a male's ejaculate. Typically, sperm production occurs in the testes and is regulated by a complex series of cellular and molecular interactions. Endoplasmic reticulum (ER) stress arises when there is a deviation from or damage to the normal functions of the ER within cells. In response to this stress, a cascade of response mechanisms is activated to regulate ER stress within cells. This study aims to investigate the role of ERstress-regulated chaperones as potential biomarkers in male infertility. ER stress associated with azoospermia can manifest in cells such as spermatogonia in the testes and can impact sperm production. As a result of ER stress, the expression and activity of a variety of proteins within cells can be altered. Among these proteins are chaperone proteins that regulate the ER stress response. The sample size was calculated to be a minimum of 36 patients ineach group. In this preliminary study, we measured and compared serum levels of protein disulfide-isomerase A1, protein disulfide-isomerase A3 (PDIA3), mesencephalic astrocyte-derived neurotrophic factor (MANF), glucose regulatory protein 78 (GRP78), clusterin (CLU), calreticulin (CRT), and calnexin (CNX) between male subjects with idiopathic nonobstructive azoospermia and a control group of noninfertile males. Serum PDIA1 (P=0.0004), MANF (P=0.018), PDIA3 (P<0.0001), GRP78 (P=0.0027), andCRT (P=0.0009) levels were higher in the infertile group compared to the control. In summary, this study presents novel findings in a cohort of male infertile patients, emphasizing the significance of incorporating diverse biomarkers. It underscores the promising role of ER stress-regulated proteins as potential serum indicators for male infertility. By elucidating the impact of ER stress on spermatogenic cells, the research illuminates the maintenance or disruption of cellular health. A deeper understanding of these results could open the door to novel treatment approaches for reproductive conditions, including azoospermia.

Expression of exosomal microRNAs miR-34a and miR-210 in male infertility: relationship with morphokinetic parameters and sperm DNA fragmentation

Introduction. Infertility affects tens of millions of men and women across the globe. In approximately half of cases, male factors are the cause of infertility. In recent decades, there has been a significant decline in the quality of male ejaculate, which is characterized by reduced sperm concentration and motility. The insufficient diagnostic and prognostic value of routine semen analysis results highlights the challenge of developing effective diagnostic tools and searching for reliable biomarkers of male infertility. One of the most promising approaches may be assessing sperm microRNA expression.Objective. To study the role of sperm exosomal microRNAs miR-34a and miR-210 in the development of male infertility.Materials &amp; methods. The retrospective study included 150 men aged 25 – 49 years; of these, 96 patients were diagnosed with idiopathic infertility. The comparison group consisted of 54 fertile men. To assess the structure and motility of sperm, the results of a standard ejaculate study (WHO, 2021) and computer data analysis using MMC Sperm (MMCSoft, St. Petersburg, Russia) software were used. The degree of DNA fragmentation was assessed using the TUNEL method. To analyze the expression of miR-34a and miR-210, quantitative real-time PCR was performed using the miRCURY LNA SYBR Green PCR Kit («Qiagen» GmbH, Hilden, Germany) and the Rotor-Gene Q PCR product detection system («Qiagen» GmbH, Hilden, Germany).Results. The study of ejaculate using the Computer Assisted Sperm Analysis System (CASA) method revealed a statistically significant relationship between the level of DNA fragmentation of sperm and indicators of the speed of their movement: rectilinear (VSL) (r = -0.522726; p &lt; 0.01), curvilinear (VCL) (r = -0.499096; p &lt; 0.01), along the middle path (VAP) (r = -0.429533; p &lt; 0.01), as well as with the amplitude of lateral head displacement (ALH) (r = -0.294779, p &lt; 0.01), the linearity of their curvilinear path (LIN) (r = -0.385796; p &lt; 0.01), the degree of straight-line movements (STR) (r = -0.268248; p &lt; 0.05) and their progressive mobility (r = -0.411547; p &lt; 0.01). A study of the level of microRNA expression in sperm exosomes revealed a statistically significant decrease in its miRNA-34a pool (p = 0.0116). According to the Chaddock scale, the strength of the correlation between miR-210 expression and the effectiveness of ART programs was moderate (0.437993). The inverse relationship between miR-34a expression and IVF and ICSI results was weak (0.135314).Conclusion. The analysis of exosomal microRNA-34a and microRNA-210, which are involved in the regulation of spermatogenesis, reveals a direct correlation between their variations and changes in the kinetic and morphological parameters of gametes. It also indicates a relationship with the state of DNA fragmentation. These findings suggest varying levels of gene expression among infertile patients, men with proven fertility, and those undergoing assisted reproductive technology (ART) treatments, both with successful and repeated unsuccessful outcomes.

The transfer of male cuticular hydrocarbons provides a reliable cue of the risk and intensity of sperm competition in decorated crickets.

Theoretically, males should increase their ejaculate expenditure when the probability of sperm competition occurring (or risk) is high but decrease ejaculate expenditure as the number of competing ejaculates (or intensity) increases. Here we examine whether male decorated crickets (Gryllodes sigillatus) use cuticular hydrocarbons (CHCs) transferred to females by rival males at mating to assess the risk and intensity of sperm competition and adjust their ejaculate accordingly. Unmated females and those perfumed with CHCs extracted from one, three, or five males could be distinguished chemically, providing a reliable cue of the risk and intensity of sperm competition. In agreement with theory, males mating with these females increased sperm number with the risk of sperm competition and decreased sperm number with the intensity of sperm competition. Similarly, as the risk of sperm competition increased, males produced a larger and more attractive spermatophylax (an important non-sperm component of the ejaculate) but these traits did not vary with the intensity of sperm competition. Our results therefore demonstrate that both sperm and non-sperm components of the male ejaculate respond to the risk and intensity of sperm competition in different ways and that CHCs provide males with an important cue to strategically tailor their ejaculate.

Male manipulation impinges on social-dependent tumor suppression in Drosophila melanogaster females

Physiological status can influence social behavior, which in turn can affect physiology and health. Previously, we reported that tumor growth in Drosophila virgin females depends on the social context, but did not investigate the underlying physiological mechanisms. Here, we sought to characterize the signal perceived between tumorous flies, ultimately discovering that the tumor suppressive effect varies depending on reproductive status. Firstly, we show that the tumor suppressive effect is neither dependent on remnant pheromone-like products nor on the microbiota. Transcriptome analysis of the heads of these tumorous flies reveals social-dependent gene-expression changes related to nervous-system activity, suggesting that a cognitive-like relay might mediate the tumor suppressive effect. The transcriptome also reveals changes in the expression of genes related to mating behavior. Surprisingly, we observed that this social-dependent tumor-suppressive effect is lost in fertilized females. After mating, Drosophila females change their behavior—favoring offspring survival—in response to peptides transferred via the male ejaculate, a phenomenon called “male manipulation”. Remarkably, the social-dependent tumor suppressive effect is restored in females mated by sex-peptide deficient males. Since male manipulation has likely been selected to favor male gene transmission, our findings indicate that this evolutionary trait impedes social-dependent tumor growth slowdown.

Peroxiredoxin 1 transfer during mating protects eupyrene sperm against oxdative stress in Grapholita molesta.

Each Grapholita molesta female only copulates once during its lifetime and thus must maintain the viability of stored eupyrene sperm for male reproductive success. The male ejaculate comprises abundant accessory gland proteins produced by the male accessory gland (AG), and many of which are major effectors for sperm storage and maintenance. Here, we reported that an antioxidant protein, peroxiredoxin 1 (GmolPrx1), secreted by the male AG, is essential for protecting eupyrene sperm from oxidative stress and maintaining their quality during storage in the female bursa copulatrix (BC). Our data showed that GmolPrx1 is highly expressed in the AG of sexually mature males. The GmolPrx1 protein is localized to the cytoplasm of AG cells and delivered to the female BC during mating. Knockdown of GmolPrx1 strongly decreased the fertility of mated females. Additionally, we evaluated oxidative status in the spermatophore of females and found that the content of hydrogen peroxide increased significantly after mating with GmolPrx1 knockdown males. Finally, the quality assessment of eupyrene sperm demonstrated that the plasma membrane integrity, acrosome integrity, and DNA integrity were all severely impaired in the spermatophore of females after mating with GmolPrx1 knockdown males, which may contribute to the fertility decline in males. Our current data demonstrated that activities of eupyrene sperm stored in females can be significantly impaired by enhanced oxidative stress through knocking down of GmolPrx1 in males. Our finding thus may further lay new foundations for the control of G. molesta through suppressing their populations by manipulating male reproductive genes. This article is protected by copyright. All rights reserved.

Male position in a sexual network reflects mating role and body size

Several species are characterised by male mating polymorphisms, which are often associated with sperm competition for which some phenotypes show specialisation. With high-resolution behavioural data, we used network analysis to quantify sperm competition intensity; the probability of overlap of the ejaculates of different males among competing male European bitterling (Rhodeus amarus) in a large experimental mesocosm. Implementing Bayesian inference with informative priors, we modelled sperm competition intensity among males adopting two alternative mating roles to understand how sperm competition intensity varied between roles as a function of body size. We demonstrated that larger males performing a “guarder” role experienced lower sperm competition intensity than smaller males. In contrast, for “sneaker males”, larger males experienced greater sperm competition intensity. We discuss these findings in the context of mating system evolution and the reproductive biology of bitterling.

THE REPRODUCTIVE ABILITY OF MALE RABBITS DEPENDING ON THE INFLUENCE OF PARATYPICAL AND GENOTYPICAL FACTORS

THE REPRODUCTIVE ABILITY OF MALE RABBITS DEPENDING ON THE INFLUENCE OF PARATYPICAL AND GENOTYPICAL FACTORS

Female factors modulate Sex Peptide’s association with sperm in Drosophila melanogaster

BackgroundMale-derived seminal fluid proteins (SFPs) that enter female fruitflies during mating induce a myriad of physiological and behavioral changes, optimizing fertility of the mating pair. Some post-mating changes in female Drosophila melanogaster persist for ~10–14 days. Their long-term persistence is because the seminal protein that induces these particular changes, the Sex Peptide (SP), is retained long term in females by binding to sperm, with gradual release of its active domain from sperm. Several other “long-term response SFPs” (LTR-SFPs) “prime” the binding of SP to sperm. Whether female factors play a role in this process is unknown, though it is important to study both sexes for a comprehensive physiological understanding of SFP/sperm interactions and for consideration in models of sexual conflict.ResultsWe report here that sperm in male ejaculates bind SP more weakly than sperm that have entered females. Moreover, we show that the amount of SP, and other SFPs, bound to sperm increases with time and transit of individual seminal proteins within the female reproductive tract (FRT). Thus, female contributions are needed for maximal and appropriate binding of SP, and other SFPs, to sperm. Towards understanding the source of female molecular contributions, we ablated spermathecal secretory cells (SSCs) and/or parovaria (female accessory glands), which contribute secretory proteins to the FRT. We found no dramatic change in the initial levels of SP bound to sperm stored in mated females with ablated or defective SSCs and/or parovaria, indicating that female molecules that facilitate the binding of SP to sperm are not uniquely derived from SSCs and parovaria. However, we observed higher levels of SP (and sperm) retention long term in females whose SSCs and parovaria had been ablated, indicating secretions from these female tissues are necessary for the gradual release of Sex Peptide’s active region from stored sperm.ConclusionThis study reveals that the SP-sperm binding pathway is not entirely male-derived and that female contributions are needed to regulate the levels of SP associated with sperm stored in their storage sites.

Pre-but not post-meiotic senescence affects sperm quality and reproductive success in the North African houbara bustard

Age-dependent reduction in reproductive success can arise due to multiple factors including a deterioration of reproductive physiology. Senescing males have been shown to produce ejaculates with poor sperm quality, which impinges on male reproductive success. In addition to individual age, gamete age can also affect male reproductive success. Accordingly, variance in male reproductive success can be due to pre-meiotic (referring to individual age) and post-meiotic senescence (sperm age). Here, we tested whether male senescence and sperm cell aging have additive or interactive effects on male reproductive success in a bird with a promiscuous mating system, the North African houbara bustard. To assess the effect of pre-meiotic aging, we compared male reproductive success between two age classes (3-6- and 12–16-year-old). To infer the effect of post-meiotic aging, male ejaculates were collected at three-time intervals following a common initial collection (day 1, 5, and 10). Therefore, day 1 ejaculates are supposed to contain younger sperm than day 5 and 10 ejaculates. Following controlled artificial inseminations, reproductive success was assessed using three fitness-linked traits (hatching success, chick growth rate and survival). In addition to reproductive output, we also assessed whether pre- and post-meiotic aging affected a wide range of sperm and ejaculate traits. In agreement with previous reports, we found that males in the older age class produced less sperm with poorer motility compared to young individuals. However, contrary to the prediction, we found that ejaculates collected at day 5 and 10 tended to have better sperm traits such as motility and velocity. The results on sperm traits were generally mirrored in the effect on reproductive success since young males produced offspring that grew faster and had better survival during the first month of life, and eggs fertilized by sperm collected at day 5 had the highest hatching success. In any of the models, there was evidence for interactive effects of male and sperm age. Overall, these results confirm the role of pre-meiotic aging on male reproductive success. The lack of evidence for sperm aging could come from the experimental design but might also reflect the pattern of mating frequency in a species with a lek-based mating system.

Postcopulatory Behavior of Tephritid Flies.

Mating produces profound changes in the behavior of female flies, such as an increase in oviposition, reduction in sexual receptivity, increase in feeding, and even excretion. Many of these changes are produced by copulation, sperm, and accessory gland products that males transfer to females during mating. Our knowledge on the function of the male ejaculate and its effect on female insects is still incipient. In this article, we review peri- and postcopulatory behaviors in tephritid flies. We address the effects of male copulatory behavior; copula duration; and the male ejaculate, sperm, and accessory gland products on female remating behavior. Many species from these families are pests of economic importance; thus, understanding male mating effects on female behavior contributes to both developing more effective environmentally friendly control methods and furthering our understanding of evolutionary implications of intersexual competition and sexual conflict.

Ejaculation: the Process and Characteristics From Start to Finish.

Semen analysis serves as the initial step in the evaluation of male infertility. However, given the difficulty in interpreting abnormal findings, physicians and patients often struggle with understanding the results. In this review, we aim to review the normal physiology of ejaculation and create an accessible resource for interpreting abnormal semen volume, viscosity, liquefaction, pH, appearance, and color. Emerging evidence has revealed that men with genitourinary tract infections have a greater number of seminal leukocytes, which may result in clumping of motile sperm and altered morphology. Hence, these patients may have abnormal sperm parameters secondary to their health status. Recent findings have further characterized the semen liquefaction process, suggesting that increased levels of semenogelin and decreased levels of proteases and plasminogen activators (e.g., urokinase and chymotrypsin) may be associated with the failure of semen to convert to a watery consistency. This article creates a resource which may be referenced when abnormalities in semen analysis are encountered. We offer a comprehensive overview of normal ejaculation physiology and abnormal variants in male ejaculate volume-including aspermia, anejaculation, retrograde ejaculation, and hypo- and hyperspermia-and their potential etiologies. Additionally, we discuss several processes (infection, inflammation, and dysfunction of male sex glands) which may affect semen viscosity, liquefaction, and pH. Finally, our discussion of the potential colors of male ejaculate is meant to reduce the anxiety of both patient and provider. Through a better understanding of the process and varying characteristics of ejaculation, physicians may adequately counsel their patients on abnormal findings and concerns regarding infertility.

CRISPR/Cas9-mediated Serine protease 2 disruption induces male sterility in Spodoptera litura.

Male fertility is essential for reproduction and population growth in animals. Many factors affect male fertility, such as courtship behavior, sperm quantity, and sperm motility, among others. Seminal Fluid Proteins (SFPs) are vital components of seminal fluid in the male ejaculate, which affect male fertility, sperm activation, and female ovulation. However, the knowledge of SFPs is insufficient; the function of many SFPs remains unknown, and most described functions were mainly characterized in Drosophila or other laboratory models. Here, we focus on the Serine protease 2 (Ser2) gene in the lepidopteran pest Spodoptera litura. The Ser2 gene was specifically expressed in male adults. Disruption of the Ser2 gene mediated by CRISPR/Cas9 induced male sterility but females remained fertile. PCR-based detection of the next-generation mutants showed that male sterility was stably inherited. The qRT-PCR analysis of SlSer2 mutants showed that motor protein family genes and structural protein family genes were down-regulated, while protein modification family genes were up-regulated, suggesting that SlSer2 may be involved in sperm movement and activity. These results demonstrate that Ser2 is an important component of SFPs in seminal fluid and was identified for a useful sterile gene for pest control that may lead to new control strategies for lepidopteran insect pests such as S. litura.

Sperm freezability is neither associated with the expression of aquaporin 3 nor sperm head dimensions in dromedary camel (Camelus dromedarius)

The expression of aquaglyceroporin 3 (AQP-3) has been demonstrated in the spermatozoa of several mammalian species and its role has been associated with cryotolerance. Post-thaw sperm quality from individual dromedary males with different response to freezing-thawing process was evaluated through sperm head morphometry. In order to understand the cellular mechanisms affected by cryoinjury we have explored the presence and distribution of sperm AQP-3 using western blotting and immunocytochemistry. WB showed different intensity of the specific signal bands at 28 kDa. Immunofluorescence assessments allowed us to identify five different and clear AQP-3 distribution patterns of labelling in the sperm plasma membrane; acrosome, post-acrosome, mid-piece, and principal and final tail. Although expression of AQP-3 varied among male ejaculates, the individual sperm response to freeze-thawing was not associated with AQP-3 expression. Thus, AQP3 expressions do not seem like a reliable predictor of sperm response to freeze-thawing process in this species. This work is the first to describe the morphometric characteristics of the heads of dromedary spermatozoa. No correlation was found between sperm head dimensions and sperm quality variables after freeze-thawing suggesting that dromedary camel sperm head morphometry is also not a reliable predictor of cryosurvival.

Effects of Larval Diet on the Male Reproductive Traits in the West Indian Sweet Potato Weevils Euscepes postfasciatus (Coleoptera: Curculionidae).

Simple SummaryIn insects, it is known that the diet during the larval stage affects traits in the adult stage. However, it is still unclear how it affects reproductive traits such as ejaculation. The ejaculate contains many proteins and therefore requires much nutrition, so the larval diet strongly influences it. Males of the West Indian sweet potato weevil Euscepes postfasciatus use accessory gland substances to inhibit remating by females. Crossing experiments were conducted using lines reared on artificial diets or sweet potato tubers during the larval stage, and the refractory period was examined. The results showed that the larval stage diet had a significant effect on the refractory period of females. We also found one protein of approximately 15 kDa in size expressed only in the treatments reared on sweet potatoes. To our knowledge, this is the first study to show that larval diet qualitatively influences male ejaculate and female refractory period.Larval diet significantly affects adult traits, although less is known about how they affect reproductive traits. Males of West Indian sweet potato weevil Euscepes postfasciatus deliver a remating inhibitor along with sperm to their mates during mating, leading to a refractory period (the period before females mate again). Crossing experiments were conducted using lines reared on artificial diets, including sweet potato powder (AD) or sweet potato tubers (SP) during the larval stage, and the refractory period was examined. We also examined whether the larval diet qualitatively or quantitatively altered male ejaculate. The results showed that the refractory period was significantly longer in the SP treatment than in the AD treatment for males and females. There was no significant difference in ejaculate volume. However, the number of sperm in the testes-seminal vesicles complex was significantly higher in the SP treatment. Additionally, SDS-PAGE revealed that the ejaculate was qualitatively different depending on the larval diet, and one protein of approximately 15 kDa in size was expressed only in the SP treatments. Revealing how larval diet affects reproductive traits in adult males will help shed light on the diverse evolution of insect mating systems and reproductive behavior.

Influence of Chronic Ethanol Intoxication on Hemodynamics in Testicles and Spermatogenesis in Middle-Aged Males

Diseases of testicles are an important social problem because according to WHO data, the male factor is about 45% in the structure of sterile marriage. Among many pathogenic factors distorting spermatogenic and endocrine function of testicles, acute and chronic circulatory disorders in them play a great role. Recent studies showed that one of the causes of male infertility is chronic ethanol intoxication causing distorted hemomicrocirculation in testicles, so determining the character of cytologic changes in them in these circumstances remains relevant.&#x0D; Objects and methods. In the study, we used 14 histological micropreparations from testicular biopsy specimens from middle-aged infertile males (22-35 years) with chronic alcoholism in anamnesis,. In some biopsy specimens, ultrastructural changes in testicles were studied under the electronic microscope, testicular hemodynamics in infertile males was examined with ultrasound.&#x0D; Results. In middle-aged infertile males with chronic alcoholism, the volume of testicles decreases compared to normal. The arterial blood flow rate in them decreases significantly. The diameter of tortuous looped seminiferous tubules decreases compared to normal. Their membrane is thickened; the layers of spermatogenic epithelial cells are reduced. The volume of interstitial endocrinocytes decreases compared to normal. Testosterone level in blood decreases too.&#x0D; Ultrastructural changes in testicles are manifested with irregular thickness and curving of spermatogenic epithelial basal membrane, vacuolization of myoid cellular, supporting epitheliocytes, and interstitial endocrinocyte cytoplasm with reduced mitochondrial cristae and tubules in the endoplasmic reticulum. In ejaculate of infertile males, sperm concentration decreases to (30.65±1.70) million/ml compared to (75.80±4.20) million/ml, the number of pathologic forms of spermatozoids increases twice, the number of spermatozoids with progressive movement decreases.

Comprehensive analysis of male ejaculate from infertile couples in the age aspect

Introduction. According to Russian Association of Urology a number of infertile couples ranges from 8 to 17.2 % in various regions of Russia. One of the causes of which is the male factor. Raising the age of the father reduces the chance of conception, increases the risk of early termination of pregnancy and the risk of certain diseases of the child. In this regard the existing knowledge of age-related changes in ejaculate parameters needs to be de veloped. This is particularly true for men of infertile couples.The study objective – to investigate the age patterns of change in the spermological status of infertile men and identify the most age-related variations.Materials and methods. Research design – observation, retrospective, crossection. Analysis of the medical records of 517 Novosibirsk male residents from couples with infertility in marriage was made. The sampling is divided into 5 age groups: 1st group (n = 108) – men of ≤29.9 years old; 2nd group (n = 171) – 30.0–34.9 years old; 3rd group (n = 130) – 35.0–39.9 years old; 4th group (n = 68) – 40.0–44.9 years old; 5th group (n = 40) – ≥45.0 years old.Results. Median of male age in total sample – 34 years, frequency of persons over 40 years – 21 %. Overall sample shows a decline in reference values of proportion of morphologically normal forms – 3.0 (1.5–5.0) % and increase in sperm DNA fragmentation index (SDFI) – 16.0 (11.0–22.2) %. In groups from 1st to 5th there is an age-specific decrease in ejaculate volume (3.5 (2.5–4.8) ml; 3.3 (2.4–4.2) ml; 3.2 (2.4–4.5) ml; 3.0 (1.7–4.9) ml; 2.7 (1.9–3.5) ml, р1–5 &lt;0.005) and sperm count (127.1 (58.8–264.0) million; 122.5 (62.4–214.0) million; 118.5 (52.8–217.5) million; 98.0 (58.5–199.5) million; 81.0 (36.5–137.9) million, р1–5, 2–5 &lt;0.005). SDFI has an age-associated increase in the value of the indicator (14.4 (10.8–19.5) %; 15.0 (10.0–21.0) %; 17.2 (11.0–22.0) %; 18.5 (14.0–24.2) %; 19.2 (13.2–29.6) %, р1–4 &lt;0.005).Conclusion. It was first time shown for the male population of Novosibirsk of Siberian Federal District that a reduction in the proportion of morphologically normal sperm below the reference values observed in the total sample and it did not depend on the age of the men examined. Only three of the examined indicators of sperm status studied infertile males had a significant age dependency: ejaculate volume decrease, reduction of total sperm, increased DNA fragmentation of sperm. The lack of a reliable influence of age on HBA-test indicators was first shown. However the trends identified require further study. The results show that age-associated increase in DNA fragmentation of sperm starts with young men under 30, and underscores the need to define SDFI in actual clinical practice. And negative processes of age influence on the quantitative, morphological and ultrastructural characteristics of sperm occur most frequently in men after 40 years.

Male condition influences female post mating aggression and feeding in Drosophila

Abstract Mating changes female behaviour and physiology across a wide range of taxa, with important effects for male and female fitness. These changes are often induced by components of the male ejaculate, such as sperm and seminal fluid proteins. However, males can vary significantly in their ejaculates, due to factors such as age, mating history or nutritional status. This male variation may therefore lead to variation in the strength of responses males can stimulate in females, with alterations in fitness outcomes for both sexes. Using the fruit fly, Drosophila melanogaster, we tested whether three aspects of male condition shape an important, but understudied, post‐mating response—increased female–female aggression. We found that females mated to old males fought less than females mated to young males. This effect was exacerbated in mates of old, sexually active males, but there was no effect of male starvation status on mating‐induced female aggression. There was also a significant effect of age and mating history on female post‐mating feeding duration. Our results add to a growing body of literature that variation in male condition can shape sexual selection through post‐mating responses in females, including female–female interactions. Studying such variation may therefore be useful for understanding how the condition of one sex affects the behaviour of the other. A free plain language summary can be found within the Supporting Information of this article.

Female Marking via Rubidium-Labeled Ejaculates in the West Indian Sweetpotato Weevil (Coleoptera: Curculionidae)

The West Indian sweetpotato weevil, Euscepes postfasciatus (Fairmaire), is one of the pests of the sweet potato, Ipomoea batatas, in tropical and subtropical countries. Although an eradication program using the sterile insect technique (SIT) for this weevil is now underway in Japan, the lack of potent attractants such as sex pheromones for this weevil species prevents effective monitoring and hampers pest control operations. New methods to monitor the performance of sterile males using trapped wild females are needed. In this study, we tested whether the ejaculate of the labeled males that were fed an artificial diet labeled with the trace element, rubidium (Rb), is detectable in the fertilized females. We fed an artificial diet treated with Rb (1.00, 0.50, 0.25, and 0.00%) to adult male weevils for 14 d after emerging and quantified the rubidium content in inseminated females. We also examined the side effects of the artificial diet on mating performance and longevity. The advantages of monitoring the spatial level of sterility using data from females labeled with ejaculate of Rb-fed males in an SIT eradication program are discussed.

Differential gene expression patterns in spermatozoa from teratospermic and normospermic domestic cats

Large percentages of abnormal sperm, termed teratospermia, are associated with poor fertility in cats, many of which are threatened with extinction from their natural habitats. Even normal appearing spermatozoa from felids with teratospermia may have a compromised capacity for motility and fertilization indicating there are factors affecting the fertilization capacity of all sperm regardless of morphology. There was a comparative study conducted using the RNA-Seq approach to identify differentially expressed genes between morphologically normal and abnormal sperm from domestic cates with normospermia and teratospermia to elucidate genes and pathways associated with abnormal sperm function. Normal sperm from cats with teratospermia have a gene expression profile similar to abnormal sperm from males with teratospermia. There was also downregulation of cGMP pathways which may be associated with a lesser sperm motility in ejaculates from males with teratospermia. Kinase phosphorylation pathways also were downregulated in normal spermatozoa from ejaculates of males with teratospermia. Results indicate that analysis of sperm gene expression provides for a more precise assessment of sperm function in semen of cats with teratospermia and facilitates identification of molecular abnormalities that may lead to compromised fertilization capacity.

Revealing mechanisms of mating plug function under sexual selection

Mating plugs are produced by many sexually reproducing animals and are hypothesized to promote male fertilization success under promiscuous mating. However, tests of this hypothesis have been constrained by an inability to discriminate ejaculates of different males in direct competition. Here, we use stable isotope labeling in vivo and proteomics to achieve this in a promiscuous rodent, Myodes glareolus We show that, although the first male's plug is usually dislodged, it can be retained throughout the second male's copulation. Retained plugs did not completely block rival sperm but did significantly limit their numbers. Differences in the number of each male's sperm progressing through the female reproductive tract were also explained by natural variation in the size of mating plugs and reproductive accessory glands from which major plug proteins originate. Relative sperm numbers in turn predicted the relative fertilization success of rival males. Our application of stable isotopes to label ejaculates resolves a longstanding debate by revealing how rodent mating plugs promote fertilization success under competitive conditions. This approach opens new opportunities to reveal cryptic mechanisms of postcopulatory sexual selection among diverse animal taxa.