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Signa are sclerotized structures located on the inner wall of the corpus bursa of female Lepidoptera whose main function is tearing open spermatophores. The sexually antagonistic coevolution (SAC) hypothesis proposes that the thickness of spermatophore envelopes has driven the evolution of the females signa; this idea is based in the fact that in many lepidopterans female sexual receptivity is at least partially controlled by the volume of ejaculate remaining in the corpus bursa. According to the SAC hypothesis, males evolved thick spermatophore envelopes to delay the post-mating recovery of female sexual receptivity thus reducing sperm competition; in response, females evolved signa for breaking spermatophore envelopes faster, gaining access to the resources contained in them and reducing their intermating intervals; the evolution of signa, in turn, favored the evolution of even thicker spermatophore envelopes, and so on. We tested two predictions of the SAC hypothesis with comparative data on the thickness of spermatophore envelopes of eleven species of Heliconiinae butterflies. The first prediction is that the spermatophore envelopes of polyandrous species with signa will be thicker than those of monandrous species without signa. In agreement with this prediction, we found that the spermatophore envelopes of a polyandrous Heliconius species with signa are thicker than those of two monandrous Heliconius species without signa. The second prediction is that in some species with signa males could enforce monandry in females by evolving “very thick” spermatophore envelopes, in these species we predict that their spermatophore envelopes will be thicker than those of their closer polyandrous relatives with signa. In agreement with this prediction, we found that in two out of three comparisons, spermatophore envelopes of monandrous species with signa have thicker spermatophore envelopes than their closer polyandrous relatives with signa. Thus, our results support the idea that selective pressures arising from sexually antagonistic interactions have been important in the evolution of spermatophore envelopes, female signa and female mating patterns.

Developing effective long-term sperm storage strategies to maintain activity requires an understanding of the underlying spermatophore developmental phase in drones. Here we compared the developmental processes and metabolites about seminal vesicles of drones from different parentages (0-24 d)in honeybee colonies, including mated queens, virgin queens, and worker bees. The results showed a similar developmental trend of seminal vesicles in thethree groups of drones on the whole, although there were significant differences in developmental levels, as well as in other indicators. Correlation analysis showed significant positive correlations between seminal vesicle width and sperm viability. The metabolomics of the seminal vesicles in drones from mated queens showed differences of the metabolites in each stage. Particularly, squalene identified among them was validated a protective effect on sperm vitality in vitro experiments. Together the results of these assays support that there were significant differences in the developmental levels of seminal vesicles among the three groups of drones in honeybees, wherein a significant correlation between sperm viability and the developmental levels of seminal vesicles were dissected. The metabolomics analysis and semen storage experiments in vitro display signatures of squalene that may act as an effective protective agent in maintaining sperm viability. Collectively, our findings indicate that spermatophore development in drones provides metabolite support, which contributes to research on the differences of sperm viability among drones in the future., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Yan, Song, Tang, Peng, Li, Yang, Zhou and Xu.)

The aim of the research, carried out on three species of terrestrial isopods – Armadillidium granulatum , Halophiloscia hirsuta and Trichoniscus alexandrae – is to bring a first consistent contribution to the knowledge of the ultrastructural organization of the testis follicles. The testis follicles are seat of a remarkable dynamic activity of their cell components (somatic cells and germ cells) that results in a continuous variation, related to the trend of spermatogenesis, of their morphology, organization and of the relationships between the two cell populations. The somatic cells, known in literature as follicular cells, nurse cells or Sertoli cells, are arranged at the periphery of the follicle to form an epithelial layer of variable thickness resting on a thin basal lamina in turn surrounded by a discontinuous network of muscle cells. In A. granulatum and H. hirsuta , two types of Sertoli cells are present: a first type, the nurse cells, envelop the spermatids in cavities within their cytoplasm and through their secretion activity play a fundamental role in the formation of the spermatophores; moreover, they phagocytizes the residual cytoplasm of spermatids. A second type of Sertoli cells shows features that leave clearly identify its supporting role to the spermatophores in formation. In T. alexandrae , instead, only one type of Sertoli cells, the nurse cell, is present, whose features are widely superimposable to those observed in the other two species. Moreover, two septa of Sertoli cells depart from the periphery of the testis follicle to constitute an articulated compartmentalization of the follicle itself, probably targeted to realize at its inside a series of microenvironments functionally diversified in order to meets the needs of the different stages of the spermatogenic cycle. [ABSTRACT FROM AUTHOR]

Direct benefits are considered to be the driving force of high female mating rates, yet species in which females do not receive material resources from males still experience increased fitness from mating frequently. One hypothesis suggests that substances within the ejaculate may boost survival or offspring production. If these materials are limiting to females, they will require continual renewal via mating and could provide a functional understanding of howhigh mating rates lead to increased female fitness. Using the Texas field cricket, Gryllus texensis, we investigated the sexual transfer of prostaglandin E2, an important mediator of invertebrate reproduction. We determined that like other gryllid species, males include significant quantities of prostaglandin E2 (PGE2) and its precursor molecule, arachidonic acid (AA), within the spermatophore. These components are passed to females during copulation and then stored within the spermatheca. We then tested the novel hypothesis that PGE2 is ephemerally available after mating and that females must frequently mate to maintain access to this limiting compound. We found that PGE2 within the spermatheca is indeed depleted through time, with only a small amount remaining 1 week after mating, but that its presence can be maintained at high quantities and for prolonged periods of time by remating. Our results support the hypothesis that high female mating rates increase the amount and availability of PGE2 throughout the breeding season, which could explain the positive relationship between female mating rate and fecundity. [ABSTRACT FROM AUTHOR]

Reproduction induces non-trivial costs, such that both males and females should choose their mates carefully and invest their resources prudently. Male performance and thus their investment into ejaculates are often predicted to decrease with age and mating frequency, which may in turn negatively affect female fitness and thus feedback on the attractiveness of old males. Such reproductive senescence may be mediated by changes in the males' oxidative status. Here, we investigated the effects of male mating frequency and age on male reproduction and oxidative status, and the respective consequences for female reproduction. We used the tropical butterfly Bicyclus anynana, in which counterintuitively older males have a higher mating success than younger ones. In once-mated males, spermatophore mass and sperm numbers strongly increased with age, while antioxidant defences and oxidative damage declined with age. In repeatedly mated males, spermatophore mass and sperm number showed little variation being similar to young once-mated males, while antioxidant defences increased and oxidative damage decreased with mating frequency. Female reproductive success was highest when mating with young once-mated males, although these produced small spermatophores with low sperm numbers. Our findings suggest that in B. anynana, (1) ejaculate size and sperm number are not reliable proxies of male quality, (2) ejaculate quality diminishes with age and mating number, and that (3) old male mating advantage likely results from sexual conflict owing negative effects on female fitness. [ABSTRACT FROM AUTHOR]

Reproduction in less favourable conditions requires genetic adaptation and/or behavioural plasticity of the organism. In order to determine the effects of these mechanisms on environment-associated variability in polyandry, a phenomenon related to reproductive success, we explored the frequency of copulations in females of nuptial gift-giving bush-cricket Pholidoptera griseoaptera (Orthoptera: Tettigoniidae) using a laboratory experiment. In a factorial design, we reared two populations originating from contrasting altitudes in two temperature treatment conditions. After 3 weeks for possible copulations in established mating groups, females (n = 108) contained between 0 and 15 spermatodoses (a proxy for the number of copulations) in their spermatheca. The mean number of spermatodoses per female did not differ either between lowland and highland populations or between warm and cold treatments. Thus, we did not observe main effects of these two factors on adaptation or plasticity. In contrast, the frequency of copulations was significantly affected by female size as log(number of spermatodoses) increased by 0.41 ± 0.27 per each 0.1 mm of pronotum length. However, interactions between the body size (the trait that predicts females' quality for reproduction) with environmental factors revealed that larger females originating from the highland population and larger females reared in cold treatment copulated more often than smaller ones, whereas females' size did not affect copulation frequency in the lowland population or in warm treatment. It suggests stronger competition among females in harsher environmental conditions, whereas effect sizes of interaction terms showed that observed mating behaviour expressed a similar extent of genetic and plastic responses to female size. This first observation of environment-associated body size-dependent mating behaviour suggests the interplay of sexual and natural selection in a nuptial gift-giving species. [ABSTRACT FROM AUTHOR]

Variation in the quality of ejaculate produced by male American lobsters, Homarus americanus Milne Edwards, 1837, has been previously described, but never quantified. This study examined the size and composition of ejaculates produced by 111 males ranging from 60 to 108 mm in carapace length (CL). Ejaculates were obtained via electrical stimulation, photographed and then processed for histology. Half of the males produced an ejaculate from each gonopore, 29% produced only one ejaculate, and the remainder (21%) produced none. Males as small as 64 mm CL produced an ejaculate containing sperm. Ejaculate weight increased with male size, but there was a negative relationship between ejaculate weight and the percent of the ejaculate that was composed of sperm mass. Variation observed in the size and composition of ejaculates produced by similarly-sized males indicates that not all males invest equally in reproduction. Additionally, larger males may invest disproportionately more in the sperm plug (acellular component), possibly as paternal assurance. [ABSTRACT FROM AUTHOR]

The objectives of this study were: (1) Compare two systems for pre-maturation of Litopenaeus vannamei in terms of spermatophore and sperm quality, (2) Compare the effect of feeds with different protein levels on reproductive quality of males reared in a biofloc-dominated system. Animals (36.40 ± 3.13 g) reared under biofloc technology ( BFT) were used in the 30-day experiment, which involved four treatments: one in a clear water system ( CW) and other three in a BFT system. The BFT treatments were differentiated by feed: mix of fish, squid and crab ( BFT+ FF) composed of 68.48% dietary protein ( DP); broodstock feed ( BFT+ BF) composed of 52.51% DP; and juvenile feed ( BFT+ JF) composed of 39.91% DP. Feed in the CW was also the mix of fresh food. Spermatophore and sperm quality were analyzed at the beginning and end of the experiment. Higher normal sperm rate was recorded in the CW compared with the BFT+ FF. Among the BFT treatments, the BFT+ FF had the lowest normal sperm rate. Thus, the use of BFT for pre-maturation of L. vannamei allowed the reduction in dietary protein levels from 68.48% ( BFT+ FF) to 39.91% ( BFT+ JF) and the maintenance of spermatophore and sperm quality compared to the system based on high daily exchange rate. [ABSTRACT FROM AUTHOR]

The role of apyrene sperm in monandrous species after sperm migration to the spermatheca has not been studied, though in polyandrous species these sperm reduce re-mating receptivity. We studied the relationship between apyrene sperm numbers and age, mating history, and fecundity in females of the monandrous pipevine swallowtail butterfly, Battus philenor (L.) that were collected in the desert of central Arizona. The number of spermatophores in the bursa copulatrix and the eggs in the ovaries were counted and their relationship to female age (as indicated by wing wear) was examined. The mean number of spermatophores in the oldest females was 1.4, confirming that this species is monandrous. Average female fecundity was estimated at 430 from counts of eggs in the ovaries. Recently mated females stored many more eupyrene sperm in the spermatheca than the number of eggs in the ovaries. Apyrene sperm were also found in the spermatheca of the females with a long period elapsed after the mating, as indicated by a collapsed spermatophore. The potential role of apyrene sperm and the effect of body size on the fecundity in monandrous species is mentioned. [ABSTRACT FROM AUTHOR]

By impacting performance of individual offspring, oviposition site choice can have a large influence on female fitness; however, a female's fitness is also impacted by her own survival and future reproductive potential. Factors influencing oviposition site selection include a female's own predation risk and nutritional needs, as well as the performance of offspring. Trade-offs may occur when oviposition sites differ in their favorability for these fitness-related functions. Adults of the leaf-mining moth, Phyllocnistis populiella, forage at the extrafloral nectaries (EFNs) of quaking aspen, Populus tremuloides. Females are synovigenic and likely rely on adult nutrition for egg production; however, proximity to EFNs may be associated with reduced offspring survival. In a controlled experiment, when given the choice of oviposition on either a leaf with or without EFNs, P. populiella preferred leaves lacking EFNs. Seven years of field survey data revealed significantly higher oviposition and lower egg predation on leaves lacking EFNs. Aspen shoots with a higher proportion of leaves expressing EFNs experienced higher oviposition but no difference in egg predation. At the leaf level, eggs were overdispersed when at low to moderate densities, likely to decrease interference competition. Females mated multiply, and the acquisition of spermatophores through repeated matings may decrease P. populiella's reliance on EF nectar for egg production. P. populiella appears to balance the trade-off between resource rich and high offspring performance sites by ovipositing in neighborhoods with a high proportion of leaves bearing EFNs, while preferring leaves lacking EFNs which experience lower egg predation. [ABSTRACT FROM AUTHOR]

Bushcrickets comprise an important group of model organisms, which are intensively studied to understand the evolution of mating behavior. During the mating process, the male bushcricket transfers a costly and edible spermatophore consisting of two parts to the female. This unique behavior makes bushcricket species appropriate study organisms for investigating spermatophore size variations across entire bushcricket family (Tettigoniidae). The functions of the spermatophylax and the ampulla, which constitute the spermatophore, have been addressed in many studies. Although the costs and benefits of mating for male and female bushcrickets may vary depending on species, there are some common evolutionary traits. In the present study, mating behaviors and spermatophore characteristics of two endemic bushcricket species, Phonochorion uvarovi and P. artvinensis, distributed at the high altitudes of the Kaçkar Mountains, northeastern Turkey, were examined. The data on two closely related species belonging to the genus of Phonochorion show that they have different reproductive investments in terms of spermatophore and sperm numbers in spite of similar habitat and nutritional preferences. P. artvinensis had a larger spermatophore, spermatophylax and ampulla, but transferred fewer sperm. Male age and weight had a significant effect on spermatophore, spermatophylax and ampulla investments in P. uvarovi while only male weight was a significant factor in P. artvinensis. A positive relationship between the spermatophylax and the ampulla weights in both species supports the ejaculate protection hypothesis in the Phonochorion species. Even though further studies on Phonochorion should be conducted to provide a more clear comparison with other groups in the barbitistine, this study demonstrates that both P. uvarovi and P. artvinensis make little spermatophore investment relative to their body size in comparison to other barbitistines. [ABSTRACT FROM AUTHOR]

Examining how the response to sperm competition risk varies in a population is essential in order to understand variation in reproductive success and mating system. In polyandrous butterflies, males transfer a large spermatophore at mating that delays female remating and confers an advantage in sperm competition. However, as large ejaculates are costly to produce-male expenditure on ejaculate size should be selected to vary with risk of sperm competition, as previously shown in the butterfly Pieris napi. In P. napi, adults can either emerge after winter diapause, or they can emerge as a directly developing generation later in the summer. Post-diapause adults have fewer developmental constraints because direct developers have to grow, develop, emerge, mate, and reproduce during a more limited seasonal timeframe, and as a result are more time-stressed. The two generations show polyphenisms in a variety of traits including polyandry, pheromone production, mating propensity, and sexual maturity at eclosion. Using these within-species, between-generation differences in ecology, we generated three important findings: (1) that both generations respond to an immediate risk of elevated sperm competition and significantly raise ejaculate investment, (2) that the diapausing generation raises this investment by a far greater 65 % increase compared with the direct generation males' 28 %, and (3) that males show a graded response relative to sperm competition risk and increase their ejaculate investment in relation to the actual level of mate competition. The difference in male mating allocation between generations may help explain life history evolution and geographic differences in mating patterns. [ABSTRACT FROM AUTHOR]

Despite the importance ofAncistrocheirus lesueuriiin the diet of a wide variety of oceanic predators, many aspects of its biology are unknown. We report new observations on the reproductive system of the species and provide age estimates of one normal and two intersexual males based on the number of increments in the statoliths. The age of the examined mature males was estimated to be more than 2 years, increasing the maximum age known for males of the species. FemaleA.lesueuriihave specific modified areas for spermatangia reception in the nuchal region. The morphology of the right hectocotylized ventral arm and the relatively large spermatophore are also described. [ABSTRACT FROM AUTHOR]

Spermatophores from coleoid cephalopods are capable of functioning autonomously during mating, attaching themselves to the female body through the “spermatophoric reaction”. In decapodiforms this attachment involves some varying degree of implantation into female tissue, herein divided into shallow and deep implantation. This paper reviews the literature concerning the phenomenon of spermatophore implantation, and presents evidence corroborating a theoretical model ascribing the role of implantation to the ejaculatory apparatus, an invaginated tube found in the spermatophore oral region. In light of parsimonious character optimizations performed on published phylogenetic trees, two hypotheses for the evolution of spermatophore transfer mechanisms are tested. One hypothesis assumes that deep implantation arose first, shallow implantation evolving later associated with the emergence of specialized receptacles. The second hypothesis assumes that shallow implantation emerged first, deep implantation arising later, possibly associated with the adoption of deep-water lifestyles. Support for each hypothesis is dependent upon the phylogeny under consideration. [ABSTRACT FROM AUTHOR]

The role of light in sexual behavior of lepidopteran species has been studied for many years because of the wide variation in the habits of moths and butterflies. Light level is important for mating of butterflies, but information on the potential role of light on sexual behavior in nocturnal moths is scanty. This study was conducted to determine the relationship between light intensity and sexual behavior in a nocturnal moth species. The mating frequency and the hourly variations of both calling behavior and sex pheromone titer in the oriental tobacco budworm Helicoverpa assulta (Guenée) (Lepidoptera: Noctuidae) were determined under several light intensities (0.0, 0.5, 5.0, and 50.0 lux). We found that 1) high-intensity light (50.0 lux) suppressed calling behavior, pheromone production, and mating; 2) low-intensity light (0.5 lux) significantly promoted female calling and mating in less time (1 h) than in complete darkness (0.0 lux); and 3) no relationship existed between sex pheromone production and calling behavior. These results suggested that low-intensity light (0.5 lux) promoted mating. This study provides reliable background information for using sex pheromones in conjunction with light traps for integrated management of nocturnal moths. [ABSTRACT FROM AUTHOR]

Persistent adaptive challenges are often met with the evolution of novel physiological traits. Although there are specific examples of single genes providing new physiological functions, studies on the origin of complex organ functions are lacking. One such derived set of complex functions is found in the Lepidopteran bursa copulatrix, an organ within the female reproductive tract that digests nutrients from the male ejaculate or spermatophore. Here, we characterized bursa physiology and the evolutionary mechanisms by which it was equipped with digestive and absorptive functionality. By studying the transcriptome of the bursa and eight other tissues, we revealed a suite of highly expressed and secreted gene products providing the bursa with a combination of stomach-like traits for mechanical and enzymatic digestion of the male spermatophore. By subsequently placing these bursa genes in an evolutionary framework, we found that the vast majority of their novel digestive functions were co-opted by borrowing genes that continue to be expressed in nonreproductive tissues. However, a number of bursa-specific genes have also arisen, some of which represent unique gene families restricted to Lepidoptera and may provide novel bursa-specific functions. This pattern of promiscuous gene borrowing and relatively infrequent evolution of tissue-specific duplicates stands in contrast to studies of the evolution of novelty via single gene co-option. Our results suggest that the evolution of complex organ-level phenotypes may often be enabled (and subsequently constrained) by changes in tissue specificity that allow expression of existing genes in novel contexts, such as reproduction. The extent to which the selective pressures encountered in these novel roles require resolution via duplication and sub/neofunctionalization is likely to be determined by the need for specialized reproductive functionality. Thus, complex physiological phenotypes such as that found in the bursa offer important opportunities for understanding the relative role of pleiotropy and specialization in adaptive evolution. [ABSTRACT FROM AUTHOR]

Levels of artificial night lighting are increasing rapidly worldwide, subjecting nocturnal organisms to a major change in their environment. Many moth species are strongly attracted to sources of artificial night lighting, with potentially severe, yet poorly studied, consequences for development, reproduction and inter/intra-specific interactions., Here, we present results of a field-based experiment where we tested effects of various types of artificial lighting on mating in the winter moth ( Operophtera brumata, Lepidoptera: Geometridae). We illuminated trunks of oak trees with green, white, red or no artificial LED light at night, and caught female O. brumata on these trunks using funnel traps. The females were dissected to check for the presence of a spermatophore, a sperm package that is delivered by males to females during mating., We found a strong reduction in the number of females on the illuminated trunks, indicating artificial light inhibition of activity. Furthermore, artificial light inhibited mating: 53% of females caught on non-illuminated trunks had mated, whereas only 13%, 16% and 28% of the females that were caught on green, white and red light illuminated trunks had mated respectively., A second experiment showed that artificial night lighting reduced the number of males that were attracted to a synthetic O. brumata pheromone lure. This effect was strongest under red light and mildest under green light., This study provides, for the first time, field-based evidence that artificial night lighting disrupts reproductive behaviour of moths, and that reducing short wavelength radiation only partly mitigates these negative effects. [ABSTRACT FROM AUTHOR]

The males of many insect species transfer a spermatophore, i.e., a proteinaceous capsule containing sperm, to females during copulation, and this may also function as a nuptial gift. If production of the spermatophore is costly and variations in the quality of females are large, males may strategically allocate their investment based on the quality of the mate to maximize their own reproductive success. We examined the size and protein content of spermatophores transferred to females of different ages and body sizes, and also to water-deprived and water-replete females in the moth Ostrinia scapulalis (Walker). Males transferred a spermatophore of a smaller size or with less protein to older females, smaller females, and water-deprived females. These results indicated that O. scapulalis males manipulated their reproductive investment based on the conditions of the mate. We also demonstrated that older males varied their resource allocation to a greater extent in response to female conditions than younger males. Thus, resource allocation by the males of this species is modulated by both female conditions and the age of the males. [ABSTRACT FROM AUTHOR]

Spermatozoa of Tettigoniidae are usually transferred to the female by means of a spermatophore which is also the site of feather-shaped spermatodesm formation. These spermatodesms are then transferred to a spermatheca, composed of a spermathecal duct and of a seminal receptacle, involved in storing spermatozoa. In order to extend the knowledge about sperm transfer and spermatodesms reorganization in the Tettigoniidae, a morpho-structural investigation was carried out on spermatophore and spermatheca of Tylopsis liliifolia and on the reorganization of the gametes from the spermatophore. Our results show that the spermatodesms undergo disorganization in the spermatophore; unlike other Tettigoniidae, however, feather-shaped spermatodesms are never found. The epithelium of the spermatheca consists of two cell types, the cuticle-forming and the gland cells, with secretory features. The gland cells, absent in the distal tract of the seminal receptacle, release their secretion in a “reservoir” where an efferent duct opens. In the distal tract of the spermathecal duct, adjacent epithelial cells show diversified ultrastructural characteristics whose probable role is discussed. A particular feature of T. liliifolia is the genesis of the feather-shaped spermatodesms in the seminal receptacle. This feature and the peculiar organization of the feather-shaped spermatodesm are a possible autapomorphy of T. liliifolia . [ABSTRACT FROM AUTHOR]

During mating, male bushcrickets transfer edible spermatophores that consist of a large sperm-free spermatophylax and a sperm-containing ampulla. The effect of consecutive matings on nuptial gift and sperm numbers in the bushcricketIsophya sikoraiwas examined. Males and females differed in body weight and mating history influenced their weight. Males differed in spermatophore weight, as well as the weights of spermatophylax and ampulla. Spermatophore (spermatophylax + ampulla) and spermatophylax weight ofI. sikoraiincreased with male body weight, but not with ampulla weight. Male age had a significant effect on sperm number, with older males producing more sperm. Female weight but not mating number of female had a significant effect on spermatophore weight. Males increased the size of the spermatophylax and sperm number when presented with larger females, but they did not adjust their ampulla weight. Male age affected spermatophylax weight when mating with heavier females. Males reached their maximal absolute sperm number point at about middle age of their mating period due to an age-dependent shift in covariation between the ampulla and spermatophylax weight and ampulla size increases over a longer period. We conclude that production of a spermatophore and its components is costly, therefore males should strategically adjust their spermatophore components among mating opportunities. Female quality is an important predictor in searching males, and those males transfer significantly larger spermatophore and ejaculates to higher quality (heavier) females. Briefly, this study suggest that maleI. sikoraistrategically allocate spermatophore size and sperm number with respect to various factors such as his age, sperm competition and female size in a multiple mating system. [ABSTRACT FROM AUTHOR]

1. The Glanville fritillary butterfly (Melitaea cinxia L.) has a small population (Ne ~ 100) on the small island of Pikku Tytärsaari (PT) in the Gulf of Finland. The population has remained completely isolated for ~100 generations, which has resulted in greatly reduced genetic variation and high genetic load (low fitness). In particular, females lay small egg clutches with a low egg-hatching rate in comparison with a large reference population in the Åland Islands (ÅL). 2. In the present study, to what extent egg clutch size and egg-hatching rate are influenced by male population and spermatophore size was analysed. 3. Spermatophore size increases with male body size, is smaller after the first mating, and is smaller in the small PT population. In the ÅL population but not in the PT population, the egg-hatching rate increases with spermatophore size. The egg-hatching rate of PT females is higher when mated with ÅL males than when mated with PT males (heterosis), but there is no such effect on clutch size. The clutch size of ÅL females is, however, reduced when mated with PT males. 4. These results indicate that both male and female traits contribute to reduced reproductive fitness in the small isolated population. [ABSTRACT FROM AUTHOR]

The Kangaroo Leech, Marsupiobdella africana , is a hermaphroditic organism, with insemination taking place by the planting of a spermatophore on another leech. Spermatophores are mostly planted on the anterior of the recipient leech, but not always. Several spermatophores may be planted by different leeches on a single recipient. The spermatophore consists of two side by side lobes. Within minutes from planting of the spermatophore, the contents are squeezed out and into the body of the recipient. Sperm are believed to find the way to the ova by following chemical cues. Kangaroo Leeches display advanced parental care by transferring fertilized eggs from the reproductive opening to a brood pouch on the ventral side. Fully developed leeches may copulate after detaching from the amphibian host Xenopus laevis, or from the Cape River Crab Potamonautes perlatus with which it maintains a phoretic association. [ABSTRACT FROM AUTHOR]

Autumn-morph adults of the Japanese Common Grass Yellow, Eurema mandarina (de l'Orza), overwinter with reproductive diapause, while the summer-morph adults do not. A low temperature and short photoperiod induce autumn-morph adults. Because of different critical photoperiods between the sexes, the summer-morph males coexist with the autumn-morph adults in late autumn. While autumn-morph males show little mating activity, mating between summer-morph males and autumn-morph females frequently occurs. Thereafter, mated autumn-morph females re-mate with autumn-morph males the following spring. Two hypotheses, a nuptial gift hypothesis and a risk-hedge hypothesis, explaining the adaptive significance of pre-overwinter copulation by autumn-morph females were examined. Wild autumn-morph females were collected in November, late March, April and early May. The decrease in the number of eggs contained in autumn-morph females indicated that they started oviposition in mid-April. The shape of the spermatophore suggested that autumn-morph females could re-mate with autumn-morph males before mid-April. Although the eupyrene sperm of the summer-morph males remained in the spermatheca just after overwintering, the nuptial gift hypothesis is more plausible than the risk-hedge hypothesis because most females re-mated in the spring before the onset of oviposition. A counter-adaptation of summer-morph males acting as a strategy for mating with autumn-morph females was also discussed. [ABSTRACT FROM AUTHOR]

The average size of spiny lobsters (Decapoda; Palinuridae) has decreased worldwide over the past few decades. Market forces coupled with minimum size limits compel fishers to target the largest individuals. Males are targeted disproportionately as a consequence of sexual dimorphism in spiny lobster size (i.e. males grow larger than females) and because of protections for ovigerous females. Therefore, overexploitation of males has led to sperm limitation in several decapod populations with serious repercussions for reproductive success. In the Caribbean spiny lobster, Panulirus argus, little is known about the effect of reduced male size on fertilization success or the role that individual size plays in gamete and larval quality. We conducted a series of laboratory experiments to test the relationship between male size and spermatophore production over multiple mating events and to determine whether spermatophore reduction and female size affected fertilization success or larval attributes in P. argus in the Florida Keys, FL (USA). We found that over consecutive matings, larger males consistently produced spermatophores of a greater weight and area than smaller males, although size-specific differences in sperm cell density were undetected and probably obscured by high variance in the data. Where spermatophores were experimentally reduced to mimic the decline in spermatophore size with declining male size, fertilization success (the number of fertilized eggs/total number of eggs extruded) declined, indicating that sperm availability is indeed limited. No maternal size effects on egg size or quality (C:N ratio) or larval quality (size, swimming speed, mortality) were observed. Our results demonstrate the importance of maintaining large males in populations of P. argus to ensure fertilization success and caution against their overexploitation through fishing, which may severely reduce reproductive success and thus population sustainability. [ABSTRACT FROM AUTHOR]

In Lepidoptera, males transfer a spermatophore to females containing sperm and accessory gland secretions that are reinvested into female reproduction, providing a fitness gain to females. One of the key factors shaping male spermatophore size is certainly the resources that males have acquired as larvae. In this study, we investigate how male larval food contributes to shaping the spermatophore quantity and quality and how it affects female reproduction in the European grapevine moth ( Lobesia botrana). Specifically, we examined the effect of male origin (cultivar or geographical site) on their mating success by scoring individual motivation to mate, male spermatophore size and amount of sperm, and finally female fecundity and fertility. A strong effect of larval cultivar was found on spermatophore size and amount of fertilizing sperm produced by males. These male characteristics had important repercussions on female reproductive output. Females mating with males producing the biggest spermatophore and more fertilizing sperm were the most fecund and fertile. Finally, females were able to recognize males of different quality during the precopulatory phase and changed their mating behavior accordingly. The present results suggest that male nutritional quality could have an important implication for population dynamics. [ABSTRACT FROM AUTHOR]

The present study is the first attempt to evaluate the use of fluorescent microscopy as a tool for determining the sperm qualitity in penaeid shrimp species. The probes propidium iodide and 6-carboxyfluorescein diacetate (CFDA) were used in combination to assess sperm quality of Litopenaeus vannamei captive broodstock and wild stocks of Farfantepenaeus subtilis and Litopenaeus schmitti. L. vannamei showed a significant higher amount of live cells (80.87%) after 93 days in captivity, when compared to animals entering (day 0) the maturation system (61.03%). The percentages of live sperm cells for wild-caught F. subtilis and L. schmitti were above 50% over the 12-month sample period in northeastern Brazil. These results demonstrate that the fluorescent microscopy can be used as a tool to determine the sperm quality in penaeid, allowing the evaluation of male performance in aquaculture systems, as well as to determine their reproductive cycle in fisheries research. [ABSTRACT FROM AUTHOR]

Macrodasyidan gastrotrichs are hermaphrodites with complex reproductive organs that function in sperm transfer and receipt, but homology among the organs of members of different clades remains undetermined, as does a broader understanding of evolutionary trends in the reproductive biology of macrodasyidans. In this study, we investigate the evolution of reproduction in Urodasys, a clade of 15 macrodasyidan species that shows variability in reproductive mode (hermaphroditic and parthenogenetic) and sexual anatomy. We use partial 18S rDNA sequence data from 30 specimens representing five described species, sequence data from one undescribed species in GenBank, and sequence data from a potentially new species found at Capron Shoal, Florida, to gain insight into the phylogeny of the clade and clarify evolutionary trends in reproductive modality. Based on a total of 33 specimens of seven potential species, we found that members of Urodasys can be separated into three clades reflective of different reproductive modalities: Clade I, species with paired male and female gonads but without accessory sexual organs; Clade II, species with a single left testis, paired ova, and accessory organs including a sclerotic stylet; and Clade III, parthenogenetic species without testes or accessory organs. In addition, we find that the potentially new species from Florida can form spermatophores, a condition shared with another species in Clade I. Herein, we describe this novel spermatophore-bearing species and discuss the significance of spermatophore formation in the genus. [ABSTRACT FROM AUTHOR]

Black rockfish ( Sebastes schlegeli) is an important species for culture; however, its reproductive characteristics have not been fully documented. In this study, we investigated the morphology and developmental process of germ cells in this ovoviviparous rockfish in reproductive season (October 2011-November 2012) with histological methods. We found that the gonad of mature fish showed notable seasonal changes in developmental characteristics and morphological structure. The sperm cells matured during a period lasting from October to December, significantly earlier than the oocytes did. A large number of spermatozoa and other cells occurred in testis at different developmental stages. Vitellogenesis in oocytes began in October, and gestation appeared in April next year. Spermatophores were discovered for the first time in Sebastes, which assembled in testis, main sperm duct, oviduct and genital tract, as well as ovarian cavity in October and April. These organs may serve either as production or hiding places for spermatophores and spermatozoa which were stored and transported in form of spermatophores. Testicular degeneration started from the distal part of testis in April, with spermatophores assembled in degenerating testis and waiting for transportation. The copulation probably lasted for a long period, during which the spermatozoa were discharged in batches as spermatophores. These spermatophores were coated with sticky materials secreted from the interstitial areas of testis and the main sperm duct, then transported into ovary. [ABSTRACT FROM AUTHOR]