Ejaculate Quality Research Articles

Song and Sperm in Crickets: A Trade-off between Pre- and Post-copulatory Traits or Phenotype-Linked Fertility?

When females mate multiply (polyandry) both pre- and post-copulatory sexual selection can occur. Sperm competition theory predicts there should be a trade-off between investment in attracting mates and investment in ejaculate quality. In contrast, the phenotype-linked fertility hypothesis predicts a positive relationship should exist between investment in attracting mates and investment in ejaculate quality. Given the need to understand how pre- and post-copulatory sexual selection interacts, we investigated the relationship between secondary sexual traits and ejaculate quality using the European house cricket, Acheta domesticus. Although we found no direct relationship between cricket secondary sexual signals and ejaculate quality, variation in ejaculate quality was dependent on male body weight and mating latency: the lightest males produced twice as many sperm as the heaviest males but took longer to mate with females. Our findings are consistent with current theoretical models of sperm competition. Given light males may have lower mating success than heavy males because females take longer to mate with them in no-choice tests, light males may be exhibiting an alternative reproductive tactic by providing females with more living sperm. Together, our findings suggest that the fitness of heavy males may depend on pre-copulatory sexual selection, while the fitness of light males may depend on post-copulatory fertilization success.

Le blessé médullaire : quel sperme et quelle prise en charge en Assistance médicale à la procréation ?

Men with spinal cord injury present a unique infertile population. Only 10 % of them can father children without medical assistance, owing to potential impairments in erection, ejaculation and semen quality. The algorithm typically followed is to retrieve semen by Penile Vibratory Stimulation, in case of failure by Electro Ejaculation. Most of these patients have normal sperm concentrations but abnormally low sperm motility and vitality in the ejaculate. The reasons for poor semen quality in spinal cord injured men are reviewed. If semen cannot be obtained by Electro Ejaculation, or if the ejaculate from Penile Vibratory Stimulation or Electro Ejaculation contains an insufficient quantity or quality of sperm for in vitro fertilization with intracytoplasmic sperm injection, then retrieval of sperm from reproductive tissues is attempted. Despite abnormal semen quality, successful pregnancies with sperm from spinal cord injured male partners have occurred by intravaginal insemination, intrauterine insemination, and in vitro fertilization with intracytoplasmic sperm injection. The prevailing pregnancy and fecundity rates in couples with a spinal cord injured male partner are reviewed.

Male Age and Experience Increases Mating Success but Not Female Fitness in the Mexican Fruit Fly

AbstractMale age and sexual experience are important condition parameters that can influence mate choice and female fitness, yet they are seldom studied simultaneously. Here, we investigated the effect of male age and previous sexual experience on mating success and female fitness in the Mexican fruit fly, Anastrepha ludens (Diptera: Tephritidae). Males were either young or old, sexually experienced or naïve. Older and sexually experienced males obtained more copulations. However, females did not receive benefits in terms of lifetime fecundity, fertility, or longevity from mating with these males. Results suggest that males become more competitive as they age and gain sexual experience and may be able to maintain a high quality ejaculate compared to young males. Older experienced males may be manipulating females into preferentially mating with them at no benefit to females. Alternatively, females may prefer mating with older more experienced males and possibly receive other indirect benefits, but this remains to be tested.

Male body size predicts sperm number in the mandarinfish

Theory predicts that, in species with non-resource-based mating systems, female preference for male sexual traits might be selected to ensure higher levels of fertility. Accordingly, secondary sexual traits used by females to assess males are expected to covary with ejaculate size and/or quality transferred during copulation, and female fecundity should be directly linked to mating with more attractive males. To date, direct tests of this hypothesis have been performed on internal fertilizing species, where several factors, such as for instance sperm competition, cryptic female choice, male parasite load, may affect ejaculate characteristics and female fecundity. Here, we used as a model the mandarinfish Synchiropus splendidus a small pelagic spawner where males only provide females with ejaculates and sperm competition does not occur. Males are significantly larger than females and we experimentally demonstrated that females prefer larger males. In addition, by collecting gametes from 67 natural spawning events, we attained a measure of the number of eggs and sperm released in each spawning event and the fertilization rates. The mean number of gametes produced positively correlates with body size in both sexes. Males do not regulate sperm number according to egg number and/or female body size. Fertilization success is significantly related to the mean number of sperm released but not directly to male body size. These findings, despite not fully accomplishing theoretical expectation, suggest that larger and more fecund females may suffer sperm limitation in mating with smaller males. In addition, our results have possible implications for the aquarium fishery of this species, which targets large males.

Male health status, signalled by courtship display, reveals ejaculate quality and hatching success in a lekking species

1. The information content of secondary sexual traits and the benefits gathered by choosy females are at the heart of sexual selection theory. Indicator models of sexual selection assume that secondary sexual traits reflect the phenotypic/genetic quality of their bearers and that females gather benefits from choosing these high-quality males. 2. Here, we tested the idea that courtship display reflects the health status in a bird species with a lek-based mating system, the houbara bustard (Chlamydotis undulata undulata). A group of males was treated with the lipopolysaccharide (LPS) of the cell wall of the bacterium Escherichia coli during the seasonal peak of courtship display, while another group of males was injected with a phosphate-buffered saline solution (PBS) as a control. We then monitored the effect of the treatment on both courtship display and ejaculate quality. Finally, females were artificially inseminated with semen from LPS and PBS males, which allowed us to assess the effect of the immunological treatment on reproduction. 3. We found that the inflammatory challenge reduced courtship display and semen quality compared to controls. Interestingly, males that better resisted to the immune challenge in terms of courtship display also better resisted in terms of ejaculate quality. Early reproductive failure was increased when females were artificially inseminated with semen from immune-activated males. Failure of eggs laid by females inseminated with LPS semen was due to a reduced fertilization power of sperm of LPS males or to increased embryo mortality in the very early stage of embryo development. As a consequence, hatching rate was reduced for females inseminated with semen collected from LPS males. 4. These results show that by assessing male courtship display, females may gain insight into the current phenotypic/genetic quality of mates and gather fitness benefits in terms of reproductive success.

Quantitative genetic evidence that males trade attractiveness for ejaculate quality in guppies

Polyandry, where females mate with multiple males, means that a male's reproductive success will depend both on his ability to acquire mates and the ability of his sperm to compete effectively for fertilizations. But, how do males partition their reproductive investment between these two episodes of selection? Theory predicts that increases in ejaculate investment will come at a cost to investment in other reproductive traits. Although evidence revealing such trade-offs is accumulating, we know little about their genetic basis. Here, I report patterns of genetic (co)variation for a range of traits subject to pre- and post-copulatory sexual selection in the guppy Poecilia reticulata, a promiscuous livebearing fish in which males alternate between courtship and sneak matings to obtain copulations. The analyses of genetic variation and covariation for these behaviours revealed a strong genetic predisposition for one tactic over the other. Both mating tactics were also strongly genetically integrated with the level of sexual ornamentation and ejaculate quality. Males that predominantly performed sneak matings were less ornamented but had faster swimming sperm than those that predominantly used courtship. These patterns of genetic variation and covariation reveal potential evolutionary constraints on the direction of selection of pre- and post-copulatory traits, and support sperm competition theory by revealing a trade-off between sexual attractiveness and investment in ejaculates.

Orchitis und Infertilität

Infections and inflammations of the genital tract are considered the most frequent causes of reduced male fertility, but conclusive epidemiological data are not available. In view of the exposure of germ cells to pathogenic components as well as the cells and mediators involved in the inflammatory processes, irreversible damage to spermatogenesis and corresponding decline of ejaculate quality are to be expected, particularly in cases of chronic orchitis. While the consequences of orchitis and epididymo-orchitis that exhibit clinical symptoms due to systemic or local infections are well known, including testicular atrophy and complete loss of fertility, those cases of inflammatory reactions of the testicles that manifest an asymptomatic or subclinical course, or are not even due to an infection, have received little attention until now. However, systematic histopathological analyses have shown a high prevalence of asymptomatic inflammatory reactions in testicular biopsies from infertile men. The mostly focal lymphocytic infiltrates correlate with the degree of damage to spermatogenesis and corresponding clinical and endocrinological parameters of testicular function. Noninvasive diagnostic techniques are not yet available so that chronic asymptomatic inflammations of the testicles as the primary cause or cofactor of male fertility disorders are underestimated. Except for administration of pathogen-specific antibiotics, treatment recommendations are to a large extent still lacking.

Plumage coloration, ejaculate quality and reproductive phenotype in the red-backed fairy-wren

Understanding how pre- and postcopulatory sexually selected traits covary can provide insight into the evolution of male ornamentation and female mate choice. In this study, we examined ejaculate quality and investment in testicular tissue in relation to plumage colour and social status in the genetically promiscuous red-backed fairy-wren, Malurus melanocephalus. In this species, males exhibit one of three alternative reproductive phenotypes during the breeding season: males can breed in red and black plumage, breed in brown plumage, or act as brown-plumed, nonbreeding auxiliaries. We found that red/ black breeders invested more heavily in spermatogenic tissue, had larger sperm reserves, and tended to have greater numbers of sperm in ejaculate samples, when compared to brown breeders and auxiliaries. Within red/black breeders, plumage redness and saturation (i.e. long wavelength hue and increased red chroma) were negatively correlated with ejaculate sample sperm density. In addition, ejaculate motility appeared to be related to variation in plumage coloration such that, overall, males with less elaborate ornamentation showed greater ejaculate quality. These results suggest that pre- and postcopulatory traits negatively covary in red/black plumed red-backed fairy-wrens and indicate a possible trade-off between investment in plumage ornaments and investment in ejaculates.

Spawning coloration and sperm quality in a large lake population of Arctic charr (Salmonidae: Salvelinus alpinus L.)

The modern theories of sexual selection predict that male sexual ornaments may have evolved as reliable signals of male fertilization efficiency. However, among the studies of fishes with external fertilization, the results have yielded ambiguous evidence. In the present study, we present data on the phenotypic relationships between red spawning coloration and ejaculate quality (spermatocrit, sperm motility) from Arctic charr, Salvelinus alpinus. We studied two generations (F1 and F2) of males from a large lake population, reared in a standardized hatchery environment, to determine whether differential hatchery history, or duration of hatchery selection, affected the variation in ejaculate characteristics or abdominal coloration. After controlling for body length, there was no difference between the hatchery generations in these traits. However, the degree of redness increased with fish size. We found a positive correlation between sperm velocity and sperm longevity, indicating a functional integration between these sperm features across generations. Sperm velocity was also positively correlated with male redness. Therefore, the finding obtained in the present study suggests that the carotenoid-based ornamentation in Arctic charr may provide information about differences between males in their fertilization potential. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 794–802.

Dose–Response Studies for Pituitary and Testicular Function in Male Dogs Treated with the GnRH Superagonist, Deslorelin

We tested the effect of dose of GnRH superagonist on pituitary and testicular function in a study with four groups of four male dogs. The Controls received blank implants and the other three groups received implants containing 3, 6 or 12 mg deslorelin (D-Trp6-Pro9-des-Gly10-GnRH ethylamide). In all deslorelin-treated groups, there was initially an acute increase in plasma concentrations of LH and testosterone, followed by declines such that both hormones became undetectable after approximately 12 days. There was a dose-response in some of these early aspects of the hormone profiles. With respect to long-term effects of treatment, the 12-mg dose had significantly greater effects than the smaller doses for the duration of minimum testicular volume [366 +/- 77, mean +/- SEM (3 mg), 472 +/- 74 (6 mg), and 634 +/- 59 (12 mg) days], absence of ejaculate [416 +/- 88 (3 mg), 476 +/- 83 (6 mg), and 644 +/- 67 (12 mg) days], undetectable plasma concentrations of LH and testosterone [367 +/- 64 (3 mg), 419 +/- 72 (6 mg), and 607 +/- 69 (12 mg) days], the delay until complete recovery of LH and testosterone secretion [394 +/- 65 (3 mg), 484 +/- 72 (6 mg) and 668 +/- 47 (12 mg) days], and the delay until testes had regrown to normal volume [408 +/- 77 (3 mg), 514 +/- 74 (6 mg), 676 +/- 59 (12 mg) days]. The time taken to restore full ejaculates was also longest for the 12-mg dose: 716 +/- 67 (12 mg) days vs 440 +/- 66 (3 mg) and 538 +/- 83 (6 mg) days after implantation. There was no correlation between delay to recovery of normal ejaculate quality and body mass. We conclude that the dose-response relationship with deslorelin implants is not expressed with respect to the degree of suppression of reproduction, but on the maximum duration of suppression and thus to delay until recovery.

Does male secondary sexual trait size reveal fertilization efficiency in Australian Drosophila bipectinata Duda (Diptera: Drosophilidae)?

Males developing relatively large, costly sexually selected traits may be of superior body condition compared to small-ornamented males. Thus, males developing the largest secondary sexual trait in a given environment may also be able to augment their investment into ejaculate quality, and fertilize a larger proportion of a female's eggs. We tested the prediction that the degree of expression of a condition-dependent secondary sexual trait, the male sex comb, in a Cape Tribulation (northeastern Australia) population of Drosophila bipectinata Duda, reveals male ability to fertilize eggs in the absence of sperm competition. This test permitted us also to evaluate whether pre-copulatory sexual selection and fertilization efficiency might act additively to influence male reproductive success because a previous study of the same population demonstrated a positive association between comb size and copulation probability. The results obtained indicate that, although genotypes developing smaller sex combs collectively had a significantly higher rate of insemination failure compared to larger comb genotypes, the hatch rate and the number of eggs laid by females inseminated by the two genotypic categories were not statistically different. The results fail to support the prediction that comb size reveals noncompetitive fertilization efficiency of males in this Australian population. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 406–413.

Prognostic value of an automated sperm analysis in IVF or insemination therapy.

During the course of sterility treatment semenograms of 271 IVF and 316 insemination patients were carried out by two automated semen analysers. The parameters of these analyses were correlated to pregnancies resulting from the treatment. Semen samples were analysed in the ejaculate and after swim-up preparation. In addition, the swim-up suspension of IVF patients was measured again 18 h after sperm preparation. Patients were divided into three groups: (1) couples who achieved a pregnancy, (2) couples who did not achieve a pregnancy, and (3) IVF patients with no fertilization of the oocytes. Because of large standard deviations in the quality of ejaculates, the results in the IVF group show no significant differences in the semen parameters of husbands of pregnant and non-pregnant women. In contrast husbands of women with no fertilization have a significantly lower sperm motility. After swim-up preparation these differences no longer occur. A further measurement, taken 18 h later, reveals that there are no differences in the sperm parameters between the pregnant and non-pregnant group. However, the semen quality in the group with no fertilization is significantly reduced. The results of the insemination patients are similar to those of the IVF group. Thus, the results from automated sperm analysers cannot replace either the microscopic or biochemical analysis of an ejaculate and, moreover, cannot be used as prognosis for the fertilization capacity of sperms or a following pregnancy.

Untersuchungen über die Wirkung von fremdem Seminalplasma auf die Verbesserung der Qualität des Ejakulates

Seminal plasma from oligozoospermic ejaculates and ejaculates with high rate of pathological spermatozoa was substituted for seminal plasma from normal ejaculates in experiments carried out in order to improve the ejaculate quality. In these experiments the improvement of ejaculate quality could not be established. The progressive increase of 20% in the motility of spermatozoa was recorded, in 4 out of 7 ejaculates with hypokinetic motility of spermatozoa where plasma was substituted, while in one case the motility remained unchanged. When plasma from normal ejaculates was substituted for plasma from ejaculates of poorer quality, the intensity of the motility of spermatozoa decreased for 10-20% in 3 of cases while in 1 it remained unchanged. Deep freezing of ejaculates after seminal plasma was substituted did not gain satisfactory results except when cases of substitution for plasma from normal ejaculates were concerned.

Reduced heterozygosity impairs sperm quality in endangered mammals

Inbreeding causes increases in homozygosity and is commonly associated with reductions in fertility and embryogenesis. Although the mechanisms underlying such effects are unknown, recent work has suggested that inbred males may suffer impaired ejaculate quality, thus providing a functional explanation for reductions in reproductive function in inbred populations. However, the relationship between inbreeding and sperm quality remains controversial, particularly in wild populations where the level of inbreeding is typically estimated using neutral molecular markers. Such markers are thought to reflect genome-wide levels of heterozygosity only under restricted conditions, and rarely in outbred populations. Here we employ a comparative approach that takes account of these criticisms and evaluates the evidence linking inbreeding to reductions in sperm quality in 20 mammal species. We focus on sperm abnormalities and sperm motility, which are key determinants of male fertility in many species. We show that species with reduced mean heterozygosity have impaired ejaculated quality, although subsequent analyses revealed that these effects were confined to endangered populations. Our findings therefore support the notion that inbreeding can severely impair sperm quality while concomitantly addressing criticisms surrounding the use of heterozygosity estimates to estimate the level of inbreeding.

Male dominance influences pheromone expression, ejaculate quality, and fertilization success in the Australian field cricket, Teleogryllus oceanicus

The outcome of fights between males can often represent an honest signal of male quality and are therefore widely used by females in mate choice. Indeed, female preference for males that win fights has been demonstrated in numerous animal taxa, and many recent studies have focused attention on how subordinate males compensate for this disadvantage through postcopulatory mating strategies, such as increased investment in their ejaculates. Here, using the Australian field cricket, Teleogryllus oceanicus, we show that rather than investing more in postcopulatory strategies, subordinate males invest in an alternative precopulatory mating approach. We find that subordinate males produce ejaculates of lower quality than dominate males and sire less offspring when competing for fertilizations. However, subordinate males upregulate the quantity of a number of cuticular compounds that have previously been shown to increase male mating success. Our results suggest that male reproductive success is likely to result from the interaction of multiple traits in this species. Key words: cuticular hydrocarbons, paternity, social status, sperm quality, Teleogryllus oceanicus. [Behav Ecol]

Secondary sexual trait size reveals competitive fertilization success in Drosophila bipectinata Duda

The evolution of male secondary sexual traits traditionally has been ascribed to precopulatory sexual selection. In contrast, the importance of postcopulatory sexual selection for the evolution of secondary sexual traits is uncertain, and what little evidence exists for this process to contribute to the evolution of such traits is mixed. Here we test the hypothesis in Drosophila bipectinata Duda that the male sex comb, a rapidly evolving secondary sexual trait, is under positive postcopulatory sexual selection. We extracted replicate genetic lines exhibiting relatively large and small sex comb size from a natural population. Males from these lines were subjected to an assay of competitive fertilization ability, measured as P2, the proportion of a female’s clutch of eggs fertilized by the second male to mate. Males with the largest sex combs sired more offspring than less ornamented individuals, demonstrating for the first time in any Drosophila species that postcopulatory sexual selection favors increasing sex comb size. This study identifies a postcopulatory selective mechanism that may be contributing to the evolutionary diversification of a secondary sexual trait. Key words: competitive fertilization success, Drosophila bipectinata, ejaculate quality, P2, postcopulatory sexual selection, sex comb size. [Behav Ecol]

Sperm Motility and Fertilizing Ability of Men with Infertility

ABSTRACTMotility is one of the main biological properties of spermatozoa that distinguishes them from the other cells in the organism. Their ability to move is of significant importance for the assessment of the ejaculate's quality—main criterion for determination of a man's fertility. The investigation of the factors effecting the motility of the spermatozoa aims to determine the relationship between the physico-chemical characteristics of the sperm, the pathology of the male reproductive tract and the mature spermatozoid.The results show that the highest percentage of spermatozoa with motility without progression is found in case of sexually-transmitted infections (7.25%), immotile spermatozoa are present mainly in case of specific inflammatory processes (44.5%) of the male reproductive system.The obtained data allow determination of spermatozoa motility rating as a marker for their fertilizing ability and for evaluation of the degree of infertility. In the present study we find that the percentage of spermatozoa with the highest mobility rating in cases of vascular and congenital diseases of the male reproductive tract is 55% and 51.67% respectively

Selection on sperm morphology under relaxed sperm competition in a wild passerine bird

Theories regarding the role of sexual selection on the evolution of sperm traits are based on an association between pre-copulatory (e.g. female preference) and post-copulatory (e.g. ejaculate quality) male reproductive traits. In tests of these hypotheses, sperm morphology has rarely been used, despite its high heritability and intra-individual consistency. We found evidence of selection for longer sperm through positive phenotypic associations between sperm size and the two major female preference traits in the pied flycatcher, Ficedula hypoleuca. Our results support the sexually selected sperm hypothesis in a species under low sperm competition and demonstrate that natural and pre-copulatory sexual selection forces should not be overlooked in studies of intraspecific sperm morphology evolution.

Ejaculate traits in relation to male body size in the eastern mosquitofish Gambusia holbrooki

In the present study, the correlation between sperm number, sperm quality (speed, viability, longevity and length), sperm bundles quality (size and dissolving rate) and male body size has been tested in the eastern mosquitofish Gambusia holbrooki a poecilid species characterized by coercive mating tactics where males do not possess obvious ornaments, and the body size is the key determinant of pre‐copulatory male mating success. The results do not tally with theoretical predictions. Indeed, no correlation between male body size and either sperm or sperm‐bundle traits has been found, evidencing the lack of the theoretically expected trade‐off between the investment in characters involved in mate acquisition and the investment in ejaculate quality. An explanation for the observed pattern comes from the extremely dynamic mating system of G. holbrooki, characterized by variable size‐related male mating success and strong post‐copulatory selective pressure, with all males facing a similar high level of sperm competition. In this situation, a higher investment in growth and maintenance at the expense of ejaculate quality is not expected. These results underscore the necessity to comprehend detailed information on species’ reproductive biology and reproductive environment to understand both the evolution of ejaculate characteristics and possible deviations from theoretical predictions.

Semen characteristics and sperm morphology of serow ( Capricornis sumatraensis)

The serow ( Capricornis sumatraensis) is a critically endangered species. The objectives of this study were to evaluate ejaculate quality in captive males, and to investigate and characterize sperm morphology. Semen was collected using electroejaculation. Mean (±S.D.) seminal characteristics were: semen volume 2.3 ± 0.8 mL, pH 7.8 ± 0.4, and osmolality 329.9 ± 32.9 mOsmol/kg; sperm concentration 515.8 ± 263.1 × 10 6 cells/mL; wave motion score (1–5) 3.9 ± 0.4; motile sperm 60.5 ± 22%; viable sperm 68.3 ± 9.4%; morphologically normal sperm 70.8 ± 19.3%; and an opacity that was yellowish to milky-white. Sperm head length, width, degree of elongation, area, and perimeter were 6.0 ± 0.6 μm, 4.3 ± 0.3 μm, 71.7 ± 8.6%, 19.8 ± 2.5 μm 2, and 17.9 ± 2.1 μm. Based on these measurements, we categorized sperm head morphometry as small, medium, or large. In addition, sperm morphology was examined by light and scanning electron microscopy; overall, morphologically normal and abnormal sperm were similar to those reported for other bovidae. In summary, this study provided baseline data regarding semen characteristics of C. sumatraensis, which should be of value in the preservation of this endangered species.