Female Sperm Storage Organs Research Articles

Costs and benefits of giant sperm and sperm storage organs in Drosophila melanogaster.

In Drosophila, long sperm are favoured in sperm competition based on the length of the female's primary sperm storage organ, the seminal receptacle (SR). This sperm-SR interaction, together with a genetic correlation between the traits, suggests that the coevolution of exaggerated sperm and SR lengths may be driven by Fisherian runaway selection. Here, we explore the costs and benefits of long sperm and SR genotypes, both in the sex that carries them and in the sex that does not. We measured male and female fitness in inbred lines of Drosophila melanogaster derived from four populations previously selected for long sperm, short sperm, long SRs or short SRs. We specifically asked: What are the costs and benefits of long sperm in males and long SRs in females? Furthermore, do genotypes that generate long sperm in males or long SRs in females impose a fitness cost on the opposite sex? Answers to these questions will address whether long sperm are an honest indicator of male fitness, male post-copulatory success is associated with male precopulatory success, female choice benefits females or is costly, and intragenomic conflict could influence evolution of these traits. We found that both sexes have increased longevity in long sperm and long SR genotypes. Males, but not females, from long SR lines had higher fecundity. Our results suggest that sperm-SR coevolution is facilitated by both increased viability and indirect benefits of long sperm and SRs in both sexes.

Is sperm morphology functionally related to sperm swimming ability? A case study in a wild passerine bird with male hierarchies

BackgroundSexual selection continues after copulation via either sperm competition or cryptic female choice, and favors sperm traits that maximize sperm competitiveness. Both sperm swimming velocity and longevity are important determinants of the outcome of sperm competition. Theoretically, sperm morphology can influence sperm velocity at least in three different non-exclusive ways: (i) longer sperm may generate more propelling thrust, (ii) bigger midpieces may produce more energy, and/or (iii) larger flagella or mid-pieces relative to the head size may compensate for the drag forces around the head. A growing number of studies have investigated the relationship of sperm morphology with sperm performance, which remains equivocal at both the inter- and intra-specific levels. Here, we used House Sparrows to test the functional relationship between sperm morphology with sperm velocity and longevity. Based on a previous study showing that sperm swimming ability covaries with social rank, we predicted that —if a functional relationship exists—1) sperm morphology should differ across social ranks, and 2) correlations between sperm morphology and sperm velocity and/or sperm longevity should be constant across social ranks.ResultsWe found no differences in sperm morphology across social ranks. Moreover, we found that sperm morphology may be correlated with sperm velocity, but such relationship varied across social ranks. This result contradicts the hypothesis of a functional relationship between sperm morphology and sperm performance. Finally, after experimentally manipulating social ranks, we observed that relationships between sperm morphology and sperm velocity and/or sperm longevity disappeared or changed direction.ConclusionsWe suggest that in species with internal fertilization, while sperm morphology is likely constrained by the morphology of the female sperm storage organs, selection may act upon physiological traits that enhance sperm performance. Hence, these two selection forces could decouple sperm performance from sperm morphology.

Long-term interaction between Drosophila sperm and sex peptide is mediated by other seminal proteins that bind only transiently to sperm

Seminal fluid proteins elicit several post-mating physiological changes in mated Drosophila melanogaster females. Some of these changes persist for over a week after mating because the seminal protein that causes these changes, the Sex Peptide (SP), binds to sperm that are stored in the female reproductive tract. SP's sperm binding is mediated by a network of at least eight seminal proteins. We show here that some of these network proteins (CG1656, CG1652, CG9997 and Antares) bind to sperm within 2 h of mating, like SP. However, while SP remains bound to sperm at 4 days post-mating, none of the other network proteins are detectable at this time. We also observed that the same network proteins are detectable at 2 h post-mating in seminal receptacle tissue from which sperm have been removed, but are no longer detectable there by 4 days post-mating, suggesting short-term retention of these proteins in this female sperm storage organ. Our results suggest that these network proteins act transiently to facilitate the conditions for SP's binding to sperm, perhaps by modifying SP or the sperm surface, but are not part of a long-acting complex that stably attaches SP to sperm.

A mating plug in a squid? Sneaker spermatophores can block the female sperm-storage organ in Doryteuthis plei

Males from numerous animal taxa have evolved strategies for obstructing the female genitalia with copulatory plugs, reducing the risk of sperm competition and thus resulting in an advantage in sexual selection. Several lines of evidence suggest that sperm competition is a common feature in the complex squid mating systems, which include the evolution of alternative mating tactics (consort vs. sneaker). However, mating plugs have hitherto not been reported for the group. Investigating the female sperm-storage organ (i.e., seminal receptacle, SR) of the squid Doryteuthis plei, we found cases in which everted spermatophores (i.e., spermatangia) were implanted into the SR and blocking its opening. Here, we describe this finding of “plugged spermatangia” based on microscopy analyses (histology and microCT) of SRs of females from three experimental groups (before and after recent mating and after egg release). We show that sneaker male spermatophores may block the opening of the SR, possibly functioning as temporary copulatory plugs that physically obstruct the SR. Together with previous experimental data on spermatophore functioning, our results suggest that plug efficiency is high until at least 5 h after mating, when spermatangia are turgid and full of sperm, clogging the organ’s opening. After that time, plugs gradually decrease their efficiency as they lose turgidity by releasing part of their sperm content. However, one experimental female still had a plugged spermatangium blocking a major portion of the opening even after 48 h without mating. Within the context of squid mating systems and sexual selection, we hypothesize that plugged spermatangia are a sneaker strategy associated with minimizing sperm competition between sneaker males.

Female ants can protect live sperm for decades with targeted immune system

![Figure][1] Sperm cells packed together in the female sperm storage organ, the spermatheca. Photo credit: Daniel Monteyne. Selecting a mate is often a life-long commitment: for species that favour monogamy, the decision is irrevocable. However, female ants go a step further. Having

A species-specific multigene family mediates differential sperm displacement in Drosophila melanogaster.

Sperm competition is a postcopulatory sexual selection mechanism in species in which females mate with multiple males. Despite its evolutionary relevance in shaping male traits, the genetic mechanisms underlying sperm competition are poorly understood. A recently originated multigene family specific to Drosophila melanogaster, Sdic, is important for the outcome of sperm competition in doubly mated females, although the mechanistic nature of this phenotype remained unresolved. Here, we compared doubly mated females, second mated to either Sdic knockout or nonknockout males, and directly visualize sperm dynamics in the female reproductive tract. We found that a less effective removal of first-to-mate male's sperm within the female's sperm storage organs is consistent with a reduced sperm competitive ability of the Sdic knockout males. Our results highlight the role young genes can play in driving the evolution of sperm competition.

Antibacterial activity of male and female sperm-storage organs in ants.

Bacteria can damage sperm and thus reduce the reproductive success of both males and females; selection should therefore favour the evolution of antimicrobial protection. Eusocial hymenopterans might be particularly affected by such bacterial infections because of their mating ecology. In both sexes, mating is restricted to a short window early in the adult stage; there are no further chances to mate later in life. Males die shortly after mating, but queens use the acquired sperm to fertilise their eggs for years, sometimes decades. The reproductive success of both sexes is, thus, ultimately sperm-limited, which maintains strong selection for high sperm viability before and after storage. We tested the antibacterial activity of the contents of the male and female sperm-storage organs - the accessory testes and the spermatheca, respectively. As our study species, we used the bacterium Escherichia coli and the garden ant Lasius niger, whose queens can live for several decades. Our results provide the first empirical evidence that male and female sperm-storage organs display different antibacterial activity. While the contents of the accessory testes actually enhanced bacterial growth, the contents of the spermatheca strongly inhibited it. Furthermore, mating appears to activate the general immune system in queens. However, antimicrobial activity in both the spermatheca and the control tissue (head-thorax homogenate) declined rapidly post-mating, consistent with a trade-off between immunity and reproduction. Overall, this study suggests that ejaculates undergo an immune 'flush' at the time of mating, allowing storage of sperm cells free of bacteria.

Severe Fertility Effects of sheepish Sperm Caused by Failure To Enter Female Sperm Storage Organs in Drosophila melanogaster.

In Drosophila, mature sperm are transferred from males to females during copulation, stored in the sperm storage organs of females, and then utilized for fertilization. Here, we report a gene named sheepish (shps) of Drosophila melanogaster that is essential for sperm storage in females. shps mutant males, although producing morphologically normal and motile sperm that are effectively transferred to females, produce very few offspring. Direct counts of sperm indicated that the primary defect was correlated to failure of shps sperm to migrate into the female sperm storage organs. Increased sperm motion parameters were seen in the control after transfer to females, whereas sperm from shps males have characteristics of the motion parameters different from the control. The few sperm that occasionally entered the female sperm storage organs showed no obvious defects in fertilization and early embryo development. The female postmating responses after copulation with shps males appeared normal, at least with respect to conformational changes of uterus, mating plug formation, and female remating rates. The shps gene encodes a protein with homology to amine oxidases, including as observed in mammals, with a transmembrane region at the C-terminal end. The shps mutation was characterized by a nonsense replacement in the third exon of CG13611, and shps was rescued by transformants of the wild-type copy of CG13611. Thus, shps may define a new class of gene responsible for sperm storage.

The morphology of the male and female reproductive system in two species of spider crabs (Decapoda: Brachyura: Majoidea) and the issue of the velum in majoid reproduction

The reproductive system of spider crabs (Majoidea) has raised considerable interest due to the complexity of female sperm storage organs. In several majoid species, the seminal receptacle has been described as being divided into a dorsal storage chamber and a ventral fertilization chamber separated by a muscular velum. The velum is supposed to control the amount of sperm used for fertilization and to play an important role in sperm competition. Here, we present a study on the reproductive systems of the two majoid species, Mithraculus sculptus (Lamarck, 1818) and Stenorhynchus seticornis (Herbst, 1788) using various morphological techniques such as μCT scans and 3D-reconstructions, complemented by paraffin histology. The male gonopods of the herein investigated species are similar in their general morphology and in the presence and distribution of setae. The tubular first gonopod holding the ejaculatory canal is much longer than the short and stout second gonopod, which is supposed to function as a piston in the transport of sperm into the female ducts. The female reproductive system of M. sculptus and S. seticornis conforms to that of other Eubrachyura in possessing paired ovaries, oviducts, seminal receptacles, vaginae, and vulvae. Based on our 3D-reconstructions we demonstrate that there is no division of the seminal receptacle into two chambers separated by a velum. In contrast to this, we observed a spatially restricted invagination of the seminal receptacle. A comparison of our data with those of previous studies, allows for the conclusion that the invagination of the seminal receptacle may have been misinterpreted and mistaken for a velum by other authors. Thus, the division of the seminal receptacle into two chambers separated by a velum is a character which needs to be re-evaluated.

Paternity analysis of wild-caught females shows that sperm package size and placement influence fertilization success in the bushcricket Pholidoptera griseoaptera.

In species where females store sperm, males may try to influence paternity by the strategic placement of sperm within the female's sperm storage organ. Sperm may be mixed or layered in storage organs, and this can influence sperm use beyond a 'fair raffle'. In some insects, sperm from different matings is packaged into discrete packets (spermatodoses), which retain their integrity in the female's sperm storage organ (spermatheca), but little is known about how these may influence patterns of sperm use under natural mating conditions in wild populations. We examined the effect of the size and position of spermatodoses within the spermatheca and number of competing ejaculates on sperm use in female dark bushcrickets (Pholidoptera griseoaptera) that had mated under unmanipulated field conditions. Females were collected near the end of the mating season, and seven hypervariable microsatellite loci were used to assign paternity of eggs laid in the laboratory. Females contained a median of three spermatodoses (range 1-6), and only six of the 36 females contained more than one spermatodose of the same genotype. Both the size and relative placement of the spermatodoses within the spermatheca had a significant effect on paternity, with a bias against smaller spermatodoses and those further from the single entrance/exit of the spermatheca. A higher number of competing males reduced the chances of siring offspring for each male. Hence, both spermatodose size and relative placement in the spermatheca influence paternity success.

Sperm metabolism is altered during storage by female insects: evidence from two-photon autofluorescence lifetime measurements in bedbugs.

We explore the possibility of characterizing sperm cells without the need to stain them using spectral and fluorescence lifetime analyses after multi-photon excitation in an insect model. The autofluorescence emission spectrum of sperm of the common bedbug, Cimex lectularius, was consistent with the presence of flavins and NAD(P)H. The mean fluorescence lifetimes showed smaller variation in sperm extracted from the male (tau m, τm = 1.54–1.84 ns) than in that extracted from the female sperm storage organ (tau m, τm = 1.26–2.00 ns). The fluorescence lifetime histograms revealed four peaks. These peaks (0.18, 0.92, 2.50 and 3.80 ns) suggest the presence of NAD(P)H and flavins and show that sperm metabolism can be characterized using fluorescence lifetime imaging. The difference in fluorescence lifetime variation between the sexes is consistent with the notion that female animals alter the metabolism of sperm cells during storage. It is not consistent, however, with the idea that sperm metabolism represents a sexually selected character that provides females with information about the male genotype.

Multiple paternity but no evidence of biased sperm use in female dumpling squid Euprymna tasmanica

Assessing the natural level of multiple paternity and sperm-use patterns provides important information regarding sperm competition and the potential for cryptic female mate choice. We developed 5 novel polymorphic microsatellites for the dumpling squid Euprymna tasmanica and used them to measure multiple paternity from both field- and laboratory-laid clutches. All clutches had multiple paternity, with a minimum of 2 to 4 sires per clutch, consistent with benefits to females of polyandry in this species, and indicating strong potential for sperm competition. We found a higher level of multiple paternity within field-laid eggs than in the first and second clutches from females that laid in the laboratory. The level of multiple paternity did not change over successive clutches from individual laboratory females and sperm from different males did not consistently dominate separate clutches, although individual females differed in patterns of sperm use. This suggests that spermatangia may be somewhat mixed within the female spermatheca at the time of fertilisation. Sperm competition is enhanced by high sperm longevity, and we found that viable sperm could be stored for up to 145 d in the laboratory. Overall, our results suggest strong potential for post-copulatory sexual selection in this species, due to the presence of sperm from multiple males in the female sperm storage organ competing for fertilisation of the female's eggs.

Seminal receptacle of the pill box crab Limnopilos naiyanetri Chuang and Ng, 1991 (Brachyura: Hymenosomatidae)

We used an histological approach to describe the female sperm storage organ (seminal receptacle) of the freshwater crab Limnopilos naiyanetri Chuang and Ng, 1991. The crescent-shaped sclerotized ventral part of the vagina (towards the gonopore) with attached abductor muscles displays structures that are similar to thoracotreme crabs. The oviduct opens into the basal (ventral) part of the receptacle. We found a secondary, additional sperm storage organ (‘bursa’) between the sclerotized ventral and the un-sclerotized dorsal part of the vagina, a feature rarely found in other brachyurans. The bursa is lined with cuticle and lacks a glandular epithelium, but is filled with free spermatozoa. We hypothesize that muscles attached to the female genital ducts could allow females to selectively permit male ejaculates access to the seminal receptacle, or direct the ejaculate into the bursa (cryptic female choice). Sperm stored in the bursa is distant from the site of fertilization, i.e., the entrance point of the oviduct into the seminal receptacle, and so differential treatment of ejaculates could translate into differential male reproductive success.

Mating and genital coupling in the primitive earwig species Echinosoma denticulatum (Pygidicranidae): implications for genital evolution in dermapteran phylogeny

Dermaptera (earwigs) shows much diversity in the genital structures, the presence of either one or two male intromittent organs (penes) being one striking aspect. The members of several groups (Karschiellidae, Eudermaptera, Arixeniina, and Hemimerina) possess a single functional penis, while others have a pair of penes. The latter condition is considered to be plesiomorphic in Dermaptera. Despite its importance for inferring the phylogeny of Dermaptera, it is presently unclear how the ancestor of earwigs acquired paired penes. To estimate the mode of mating and sperm transfer in the common ancestor of extant earwigs, this study examines the mating behavior and genital coupling of the primitive earwig species Echinosoma denticulatum Hincks, 1959 as a representative of Pygidicranidae, one of the basal-most assemblages of earwigs. Staged mating experiments, including surgical manipulation of male penes revealed the following characteristics for this species: (1) males use only one of the paired penes for a single genital coupling; (2) both penes are likely functional; (3) there are no consistent biases in usage of the penes; (4) laterality of the penis-use pattern is not related to the direction of rotation of the male abdomen to establish genital coupling; (5) sperm are transferred directly into the spermatheca, a female sperm storage organ; (6) the spined area of the penis inflicts wounds on the vagina around the spermathecal opening, which bears many setae, during copulation. Characteristics (1)–(4) are considered to be plesiomorphic and may represent the condition of the common ancestor. Traumatic penetration during copulation is reported for earwigs for the first time. Together with intermittent acceptance of courting males by females only after a certain interval, these results suggest sexual conflict over mating in this species.

The developmental plasticity and functional significance of an additional sperm storage compartment in female yellow dung flies

Summary The mechanistic basis for and adaptive significance of variation in female sperm storage organs are important for a range of questions concerning sexual selection and speciation, as such variation influences the evolutionary trajectories of male fertilization related traits and may facilitate speciation through its effects on gamete recognition. Female yellow dung flies (Scathophaga stercoraria) usually develop three sperm storage compartments, and this subdivision may be an adaptation for sorting sperm during postcopulatory choice. Using lines artificially selected to express four spermathecae (4s), we explored the fitness consequences of the novel phenotype relative to the naturally prevalent three‐spermatheca (3s) phenotype by manipulating the opportunity for postcopulatory sexual selection (females mated either with three or only one male prior to oviposition). In addition, we examined the developmental plasticity of spermathecal number in response to different larval food environments and estimated its genetic correlation with growth rate. Mating treatments with and without the opportunity for postcopulatory sexual selection revealed no significant fitness differences between alternative spermathecal phenotypes within selection lines despite overall benefits associated with multiple mating, and moderate egg‐to‐adult survival costs in response to artificial selection for 4s. Manipulations of the larval food environment revealed that the expression of 4s is highly plastic and tightly linked to environmental conditions promoting fast somatic growth and development. Likewise, siblings with fast intrinsic (genetic) growth were more likely to express 4s within and across food environments. The present results highlight a great potential for rapid evolutionary change in female sperm storage morphology through indirect selection on life‐history traits, and further suggest genetic assimilation as a potential mechanism facilitating phylogenetic transitions in spermatheca number as frequently observed within the Dipterans.

Body Size and Morph as Drivers of Copulation Duration in a Male Dimorphic Damselfly

AbstractCopulation duration is often highly variable within and among species. Here, we explore the roles of body size, male morph, morph frequency, and alternative reproductive tactics to explain copulation duration in the damselfly Paraphlebia zoe. P. zoe has two male morphs (pigmented or hyaline wings) which differ in reproductive tactics (territorial or non‐territorial behaviors). We also analyze the effects of season as the frequencies of both morphs tend to vary along the reproductive season. In the first non‐experimental year, we found that the relationship between body size and copulation duration depended on the time of year. Early in the season, body size positively correlated with copulation duration, while late in the year, body size negatively correlated with copulation duration. In the second experimental year (when we reversed the frequency of male morphs in the middle of the season: making pigmented males less frequent than hyaline males), size influenced copulation duration as well as morph – body size positively correlated with copulation duration, and hyaline males mated for longer than pigmented males. Contrary to our prediction, changes to the relative abundances of morphs did not influence copulation duration. Hyaline males may be under selection for longer copulation durations to compensate for their reduced access to females, as long copulations potentially lead to more rival sperm to be removed from the female sperm storage organs and/or increased mate guarding. We do not discard, however, other explanations that drive variation in copulation duration such as cryptic female choice and/or predation.

Silencing of the Hsf gene, the transcriptional regulator of A. gambiae male accessory glands, inhibits the formation of the mating plug in mated females and disrupts their monogamous behaviour

Discovering the molecular factors that shape the mating behaviour and the fertility of the mosquito Anopheles gambiae, the principal vector of human malaria, is regarded as critical to better understand its reproductive success as well as for identifying new leads for malaria control measures. In A. gambiae mating induces complex behavioural and physiological changes in the females, including refractoriness to subsequent mating and induction of egg-laying. In other insects including Drosophila a group of proteins named Accessory gland proteins (Acps), produced by males and transferred with sperm to the female reproductive tract, have been implicated in this post-mating response. Although Acps represent a set of promising candidates for unravelling the mating physiology, their role in inducing behavioural changes in mated A. gambiae females remains largely unknown. In this work, we demonstrate that a down-regulation of a large fraction of Acp genes via silencing of the Acp regulating transcription factor Hsf, abolishes the formation of mating plug in mated females and fails to induce refractoriness of mated female to subsequent inseminations. A significant fraction of females mated to Hsf silenced males (66%) failed to receive the mating plug though seminal fluid had been transferred as documented by the presence of spermatozoa in the female sperm storage organ. Furthermore, nearly all females (95%) mated to HSF-silenced males were re-inseminated when exposed to males carrying EGPF marked sperm. Our findings provide evidence showing that Acp genes regulated by the transcription factor HSF play a key role in the function of the male accessory glands.

Sperm of the wasted mutant are wasted when females utilize the stored sperm in Drosophila melanogaster

Females of many animal species store sperm after copulation for use in fertilization, but the mechanisms controlling sperm storage and utilization are largely unknown. Here we describe a novel male sterile mutation of Drosophila melanogaster, wasted (wst), which shows defects in various processes of sperm utilization. The sperm of wst mutant males are stored like those of wild-type males in the female sperm storage organs, the spermathecae and seminal receptacles, after copulation and are released at each ovulation. However, an average of thirteen times more wst sperm than wild type sperm are released at each ovulation, resulting in rapid loss of sperm stored in seminal receptacles within a few days after copulation. wst sperm can enter eggs efficiently at 5 hr after copulation, but the efficiency of sperm entry decreases significantly by 24 hr after copulation, suggesting that wst sperm lose their ability to enter eggs during storage. Furthermore, wst sperm fail to undergo nuclear decondensation, which prevents the process of fertilization even when sperm enter eggs. Our results indicate that the wst gene is essential for independent processes in the utilization of stored sperm; namely, regulation of sperm release from female storage organs, maintenance of sperm efficiency for entry into eggs, and formation of the male pronucleus in the egg at fertilization.

Determinants of female fecundity in a simultaneous hermaphrodite: the role of polyandry and food availability

Classical sexual selection theory assumes that the reproductive success of females is primarily limited by the resources available for egg production rather than by the number of mating partners. However, there is now accumulating evidence that multiple mating can entail fitness costs or benefits for females. In this study we investigated the effect of polyandry (i.e., the mating with different mating partners) and food availability on the reproductive output of the female sex function in an outcrossing simultaneous hermaphrodite, the free-living flatworm Macrostomum lignano. We exposed virgin worms to different group sizes, a treatment that has previously been shown to affect the level of polyandry in this species. Moreover, we manipulated the food availability throughout the subsequent egg laying period, during which the worms were kept in isolation. The number of offspring produced was used as an estimate of female fecundity. We found that food availability, but not group size, had a significant effect on female fecundity. Additionally, female fecundity was positively correlated with the number of stored sperm in the female sperm-storage organ at the time of isolation, but it was not correlated with body or ovary size of the worms. Our results suggest that female fecundity in M. lignano is primarily determined by the resources available for egg production, and not by the level of polyandry, confirming classic sexual selection theory for simultaneous hermaphrodites.

Isolating, Amplifying and Quantifying Sperm DNA inAnastrepha suspensa(Diptera: Tephritidae)

A major obstacle for many studies examining sperm competition and cryptic female choice in insects has been the identification and quantification of sperm stored in the sperm storage organs of females that have mated with two or more males. Historically, sexual selection studies have focused primarily on paternity outcomes for inferring potential underlying mechanisms (e.g., sperm competition and cryptic female choice). We describe a technique for isolating, genotyping and quantifying sperm in Anastrepha suspensa Loew, a species that has four sperm storage organs (three spermathecae and a ventral receptacle) that are minute (approximately 80 µm) and exhibit complex interior structures restricting sperm recovery through simple dissection. With our protocol, we were able to isolate and amplify sperm DNA (PCR of microsatellite loci) without contamination from female cells, and quantify sperm contributed to a storage organ by one or more males. Briefly, sperm storage organs are dissected-out of the female abdomen, sonicated to remove female cells, rinsed in saline, crushed between micro-slides (1 × 2 mm), and placed in a microcentrifuge tube for DNA isolation in situ using a solution containing 10% chelex, proteinase-K and DTT. After boiling, the DNA is amplified by PCR. With this technique, we have successfully amplified microsatellite loci from as few as 10 ± 3 sperm. Estimates of absolute numbers of sperm stored in sperm storage organs was accomplished by incorporating a reference amplicon standard in each sample during fragment analysis of microsatellite loci. The protocol described in this study enable the localization, identification and quantification of sperm from multiple males stored in female sperm storage organs and, therefore, generates data that can augment interpretations of paternity outcomes.Translation provided by the authors.