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1.
Recent evidence shows that females exert a post‐copulatory fertilization bias in favour of unrelated males to avoid the genetic incompatibilities derived from inbreeding. One of the mechanisms suggested for fertilization biases in insects is female control over transport of sperm to the sperm‐storage organs. We investigated post‐copulatory inbreeding‐avoidance mechanisms in females of the cricket Teleogryllus oceanicus. We assessed the relative contribution of related and unrelated males to the sperm stores of double‐mated females. To demonstrate unequivocally that biased sperm storage results from female control rather than cryptic male choice, we manipulated the relatedness of mated males and of males performing post‐copulatory mate guarding. Our results show that when guarded by a related male, females store less sperm from their actual mate, irrespective of the relatedness of the mating male. Our data support the notion that inhibition of sperm storage by female crickets can act as a form of cryptic female choice to avoid the severe negative effects of inbreeding. 相似文献
2.
M. Otronen 《Proceedings. Biological sciences / The Royal Society》1997,264(1382):777-782
In the fly Dryomyza anilis females have two kinds of sperm storage organs: one bursa copulatrix and three spermathecae (two spermathecae with a common duct form the doublet, and the third is a singlet spermathecal unit). At the beginning of a mating the male deposits his sperm in the bursa copulatrix. After sperm transfer the male taps the female''s abdomen with his claspers. This behaviour has been shown to increase the male''s fertilization success. After mating, the female discharges large quantities of sperm before oviposition. To find out where the sperm remaining in the female are stored, I counted the number of sperm in the droplet and in the female''s sperm storage organs after different types of mating. I carried out three mating experiments. In experiment 1, virgin females were mated with one male and the matings were interrupted either immediately after sperm transfer or after several tapping sequences. The results show that during male tapping more sperm moved into the singlet spermatheca. In addition, the total number of sperm correlated with sperm numbers in all sperm storage organs, and male size was positively related to the number of sperm remaining in the bursa. In experiment 2, females mated with several males. The number of sperm increased with increasing number of matings only in the doublet spermatheca. No increase in the number of sperm in the singlet spermatheca during consecutive matings suggests that sperm were replaced or did not reach this sperm storage organ. In experiment 3, virgin females were mated with a single male and half of them were allowed to lay eggs. The experiment showed that during egglaying, females primarily used sperm from their singlet spermatheca. The results from the three experiments suggest that sperm stored in the singlet spermatheca is central for male fertilization success and male tapping is related to sperm storage in the singlet spermatheca. The different female''s sperm storage organs in D. anilis may have separate functions during sperm storage as well as during sperm usage. 相似文献
3.
Sperm storage organs allow females to temporally separate insemination from fertilization, manipulate ejaculates and control fertilization. In the reproductive tract of female fruit flies (Diptera: Tephritidae), sperm are found in two different organs--a pair or triplet of spermathecae, and a "fertilization chamber". In order to understand the specific function of each of these organs, we tested the following hypotheses: (1) Sperm are distributed equally amongst the various sperm storage organs; (2) Both organ types maintain sperm viability; and (3) Sperm used in fertilization come from the fertilization chamber. We counted sperm in spermathecae and fertilization chamber of Mediterranean fruit flies (Ceratitis capitata) every 3 days for 18 days following insemination, and used a live/dead staining technique to determine the viability of sperm in these organs. Finally, by extirpating spermathecae from inseminated females and allowing them to oviposit, we were able to identify the fertilization chamber as the source of fertilizing sperm. Numbers of sperm in the spermathecae declined from an average of 3575 on the day of copulation to 649, 18 days later. Conversely, the fertilization chamber maintained a fairly constant level of sperms, ranging between an average of 207 cells on day 3 to 115 sperms on day 18. Throughout the period we monitored, we found high levels of sperm viability in both organs (> 80%). Sperm viability was similarly high in the fertilization chambers of females without spermathecae. However, fertility of eggs laid by these females declined rapidly, as did the number of sperm in the fertilization chamber. We conclude that both the spermathecae and the fertilization chamber are active sperm storage organs, with separate functions: the spermathecae for long-term storage and the fertilization chamber, periodically filled by the spermathecae, a staging point for fertilizing sperm. We suggest that the use of both organs by females results in sperm economy, which adaptively prolongs the intervals between copulations. 相似文献
4.
We studied changes in the number of sperm within two kinds of female sperm-storage organ in the damselfly Ischnura senegalensis (Odonata: Coenagrionidae): the bursa copulatrix and the spermatheca. We counted the number of sperm within each storage organ and tested their viability after a single copulation in female damselflies kept for seven days with and without oviposition. We also counted sperm and tested their viability in females that underwent an interrupted second copulation after the sperm-removal stage, and after subsequent oviposition. Our results showed that the bursa copulatrix and spermatheca have different sperm storage roles. Immediately after copulation, most eggs appear to have been fertilized with bursal sperm, which were positioned near the fertilization point. By seven days after copulation, a greater proportion of spermathecal sperm were used for fertilization, as the number of bursal sperm had decreased. We hypothesize that female damselflies use the spermatheca for long-term storage and the bursa copulatrix for short-term storage: bursal sperm are more likely to be used for fertilization but may have a higher risk of mortality due to sperm removal by a competing male and/or sperm expelling by the female, whereas spermathecal sperm are safer but will be used for fertilization only after their release from the spermatheca. 相似文献
5.
K. Reinhardt G. K hler J. Schumacher 《Proceedings. Biological sciences / The Royal Society》1999,266(1432):2003
The evolution of female multiple mating is still a largely debated field. Among the benefits that have been proposed to explain this risky behaviour is the replenishment of sperm reserves. Apart from an increase in total sperm number, it can be an expression of post-copulatory mate choice or can be directed towards the uptake of fresh sperm. Using fresh sperm for fertilization instead of sperm aged by storage in the female genital tract may avoid a lowered fertilization capacity, an increase in deleterious effects or a skewed offspring sex ratio. We investigated the influence of sperm age on female fitness in the grasshopper Chorthippus parallelus, a species where females mate multiply. After copulation, females store sperm over the course of weeks until fertilization. An average ejaculate of 250 000 spermatozoa exponentially declined with time within the female''s spermatheca. The number of days since copulation better explained the variation in actual sperm number than the number of pods or eggs laid. We investigated differences in female fitness parameters in two treatments. In the first, females were mated only once, while in the second, females always had freshly ejaculated sperm available. Although in our experiment, multiply mated females had heavier offspring than singly mated females, egg number per pod, hatching and fertilization success, their composite effects and offspring sex ratio did not vary with respect to season or sperm age. We therefore reject the hypothesis that the reason for remating in females of this species is the uptake of fresh sperm. 相似文献
6.
Karl P. Phillips Tove H. Jorgensen Kevin G. Jolliffe San‐Marie Jolliffe Jock Henwood David S. Richardson 《Molecular ecology》2013,22(8):2301-2312
Postcopulatory sperm storage can serve a range of functions, including ensuring fertility, allowing delayed fertilization and facilitating sexual selection. Sperm storage is likely to be particularly important in wide‐ranging animals with low population densities, but its prevalence and importance in such taxa, and its role in promoting sexual selection, are poorly known. Here, we use a powerful microsatellite array and paternal genotype reconstruction to assess the prevalence of sperm storage and test sexual selection hypotheses of genetic biases to paternity in one such species, the critically endangered hawksbill turtle, Eretmochelys imbricata. In the majority of females (90.7%, N = 43), all offspring were sired by a single male. In the few cases of multiple paternity (9.3%), two males fertilized each female. Importantly, the identity and proportional fertilization success of males were consistent across all sequential nests laid by individual females over the breeding season (up to five nests over 75 days). No males were identified as having fertilized more than one female, suggesting that a large number of males are available to females. No evidence for biases to paternity based on heterozygosity or relatedness was found. These results indicate that female hawksbill turtles are predominantly monogamous within a season, store sperm for the duration of the nesting season and do not re‐mate between nests. Furthermore, females do not appear to be using sperm storage to facilitate sexual selection. Consequently, the primary value of storing sperm in marine turtles may be to uncouple mating and fertilization in time and avoid costly re‐mating. 相似文献
7.
Margaret C. Bloch Qazi 《Journal of insect physiology》2010,56(9):1332-1340
Among many species of insects, females gain fitness benefits by producing numerous offspring. Yet actions related to producing numerous offspring such as mating with multiple males, producing oocytes and placing offspring in sub-optimal environments incur costs. Females can decrease the magnitude of these costs by retaining gametes when suitable oviposition sites are absent. We used the pomace fly, Drosophila melanogaster, to explore how the availability of fresh feeding/oviposition medium influenced female fitness via changes in offspring survivorship and the modulation of gamete release. Availability of fresh medium affected the absolute number and temporal production of offspring. This outcome was attributable to both decreased larval survival under crowded conditions and to female modulation of gamete release. Direct examination of the number of sperm retained among the different female storage organs revealed that females ‘hold on’ to sperm, retaining more sperm in storage, disproportionately within the spermathecae, when exposed infrequently to fresh medium. Despite this retention, females with lower rates of storage depletion exhibited decreased sperm use efficiency shortly after mating. This study provides direct evidence that females influence the rate of sperm depletion from specific storage sites in a way that can affect both female and male fitness. The possible adaptive significance of selective gamete utilization by female Drosophila includes lowering costs associated with frequent remating and larval overcrowding when oviposition sites are limiting, as well as potentially influencing paternity when females store sperm from multiple males. 相似文献
8.
Barbara A. Caspers E. Tobias Krause Ralf Hendrix Michael Kopp Oliver Rupp Katrin Rosentreter Sebastian Steinfartz 《Molecular ecology》2014,23(1):239-250
Although classically thought to be rare, female polyandry is widespread and may entail significant fitness benefits. If females store sperm over extended periods of time, the consequences of polyandry will depend on the pattern of sperm storage, and some of the potential benefits of polyandry can only be realized if sperm from different males is mixed. Our study aimed to determine patterns and consequences of polyandry in an amphibian species, the fire salamander, under fully natural conditions. Fire salamanders are ideal study objects, because mating, fertilization and larval deposition are temporally decoupled, females store sperm for several months, and larvae are deposited in the order of fertilization. Based on 18 microsatellite loci, we conducted paternity analysis of 24 female‐offspring arrays with, in total, over 600 larvae fertilized under complete natural conditions. More than one‐third of females were polyandrous and up to four males were found as sires. Our data clearly show that sperm from multiple males is mixed in the female's spermatheca. Nevertheless, paternity is biased, and the most successful male sires on average 70% of the larvae, suggesting a ‘topping off’ mechanism with first‐male precedence. Female reproductive success increased with the number of sires, most probably because multiple mating ensured high fertilization success. In contrast, offspring number was unaffected by female condition and genetic characteristics, but surprisingly, it increased with the degree of genetic relatedness between females and their sires. Sires of polyandrous females tended to be genetically similar to each other, indicating a role for active female choice. 相似文献
9.
David M Sever 《The Journal of experimental zoology》2002,292(2):165-179
The three orders of extant amphibians are Gymnophiona, Anura, and Urodela. Although all gymnophionans apparently have internal fertilization and many are viviparous, female sperm storage is unknown. Internal fertilization has convergently evolved in a few anurans, but females of just one species, Ascaphus truei, are known to possess oviductal sperm storage tubules (SSTs). The SSTs of A. truei are similar anatomically to such glands in squamate reptiles. This similarity is convergence due to similar functional adaptations and/or internal design constraints. In salamanders and newts (Urodela), absence of sperm storage in females is the ancestral condition (three families). In the derived condition, sperm storage occurs in cloacal glands called spermathecae, and their possession is a synapomorphy for females in the suborder Salamandroidea (seven families). Salamandroids are the only vertebrates with cloacal sperm storage glands. In this paper, a phenetic analysis of variation in spermathecal characters reveals patterns of convergence in certain spermathecal characters in unrelated taxa that breed in similar habitats. In the family Salamandridae, a role in sperm nutrition for the spermathecal epithelium is questioned, and the widespread occurrence of spermiophagy is related to other reproductive strategies. I propose how the packaging of sperm in structurally different types of spermathecae may influence male paternity. 相似文献
10.
Honey bee males and queens use glandular secretions to enhance sperm viability before and after storage 总被引:1,自引:0,他引:1
Internal fertilization requires live sperm to be transferred from male to female before egg fertilization. Both males and females assist the insemination process by providing sperm with glandular secretions, which have been inferred to contain subsets of proteins that maintain sperm viability. Here we show that in the honeybee (Apis mellifera) secretions of the male accessory glands, the major contributors towards seminal fluid, enhance sperm survival. We further demonstrate that the protein fraction of the male accessory gland secretion is indeed important for achieving the maximal effect on sperm survival. After sperm storage, the queens also provide sperm with secretions from spermathecal glands and we show that these secretions have a comparable positive effect on sperm viability. SDS gels show that the proteomic profiles of accessory gland secretion and spermathecal fluid secretion hardly overlap, which suggests that males and females use different proteins to enhance sperm viability during, respectively, ejaculation and final sperm storage. 相似文献
11.
12.
In most insects, sperm transferred by the male to the female during mating are stored within the female reproductive tract for subsequent use in fertilization. In Drosophila melanogaster, male accessory gland proteins (Acps) within the seminal fluid are required for efficient accumulation of sperm in the female's sperm storage organs. To determine the events within the female reproductive tract that occur during sperm storage, and the role that Acps and sperm play in these events, we identified morphological changes that take place during sperm storage in females mated to wild-type, Acp-deficient or sperm-deficient males. A reproducible set of morphological changes occurs in a wild-type mating. These were categorized into 10 stereotypic stages. Sperm are not needed for progression through these stages in females, but receipt of Acps is essential for progression beyond the first few stages of morphological change. Furthermore, females that received small quantities of Acps reached slightly later stages than females that received no Acps. Our results suggest that timely morphological changes in the female reproductive tract, possibly muscular in nature, may be needed for successful sperm storage, and that Acps from the male are needed in order for these changes to occur. 相似文献
13.
Sperm form and size is tremendously variable within and across species. However, a general explanation for this variation is lacking. It has been suggested that sperm size may influence sperm competition, and there is evidence for this in some taxa but not others. In addition to normal fertilizing sperm, a number of molluscs and insects produce nonfertile sperm that are also extremely morphologically variable, and distinct from fertilizing forms. There is evidence that nonfertile sperm play an indirect role in sperm competition by decreasing female remating propensity in Lepidopterans, but in most taxa the function of parasperm is unknown. We investigated the role of nonfertile (oligopyrene) sperm during sperm competition in the fresh water snail Viviparus ater. Previous studies found that the proportion of oligopyrene sperm increased with the risk of sperm competition, and hence it seems likely that these sperm influence fertilization success during competitive matings. In mating experiments in which females were sequentially housed with males, we examined a range of male characteristics which potentially influence fertilization success. We found that the size of oligopyrene sperm was the best predictor of fertilization success, with males having the longer sperm siring the highest proportion of offspring. Furthermore, we found a positive shell size and sperm concentration effect on paternity, and females with multiply sired families produced more offspring than females mating with only one male. This result suggests polyandry is beneficial for female snails. 相似文献
14.
In animals having internal fertilization, both sexes can potentially influence the post-copulatory processes of sperm transfer, sperm storage and sperm use for fertilization. In this experiment, we investigated whether Tribolium castaneum females can influence male paternity success following consecutive matings with two different males. We compared second male paternity success (P2) between females exposed to carbon dioxide (CO2) and control females kept in air, in both cases for 30 min between two matings. CO2 exposure inhibits muscular activity and has previously been shown to decrease sperm storage by T. castaneum females. Females exposed to CO2 after their first mating showed significantly higher P2 than control females during the later portion of a one-month oviposition period. These results are consistent with reduced storage of first male sperm by CO2-exposed females. Also, T. castaneum females showed considerable variation in spermathecal morphology, and P2 decreased with increasing spermathecal tubule volume. These results demonstrate that T. castaneum females can influence male paternity success, and suggest that differential sperm storage may be an important mechanism of post-copulatory female choice. 相似文献
15.
Polyspermy is a major puzzle in reproductive biology. In some taxa, multiple sperm enter the ovum as part of the normal fertilization process, whereas in others, penetration of the ovum by more than one sperm is lethal. In birds, several sperm typically enter the germinal disc, yet only one fuses with the female pronucleus. It is unclear whether supernumerary sperm play an essential role in the avian fertilization process and, if they do, how females regulate the progression of sperm through the oviduct to ensure an appropriate number reach the ovum. Here, we show that when very few sperm penetrate the avian ovum, embryos are unlikely to survive beyond the earliest stages of development. We also show that when the number of inseminated sperm is limited, a greater proportion than expected reach and penetrate the ovum, indicating that females compensate for low sperm numbers in the oviduct. Our results suggest a functional role for supernumerary sperm in the processes of fertilization and early embryogenesis, providing an exciting expansion of our understanding of sperm function in birds. 相似文献
16.
Sabrina Bertin Francesca Scolari Carmela R. Guglielmino Angelica Bonomi Ludvik M. Gomulski Anna R. Malacrida Carlo Matessi 《Journal of insect physiology》2010,56(11):1542-1551
The medfly, Ceratitis capitata, is an invasive species in which polyandry, associated with sperm precedence, is a common behaviour in the wild. In this species, characterized by internal fertilization, we disclose how the sperm from two males are stored in the female storage organs and how they are used in terms of paternity outcome. The experiments were designed to furnish comparable and unbiased estimates of sperm numbers and progeny in twice-mated females. Results are incorporated in a model through which it is possible to relate the amount of stored sperm with the progeny of twice-mated females. The results show that polyandrous medfly females conserve equal amounts of sperm from the two males to fertilize their eggs. However, we observed a clear advantage of the second male's sperm in siring progeny, which interestingly decreases in favor of the first male as ovipositions progress. The results enable us to exclude differential sperm mortality and suggest that it is the mechanics governing the storage organs which causes the initial, but decreasing second male sperm precedence during the female reproductive life. These outcomes allow us to correlate sperm use in polyandrous females with the mating strategies and invasiveness of this fly. 相似文献
17.
Solana Abraham Andrea Moyano Viviana Díaz M. Gabriela Murúa Juan Rull 《Insect Science》2023,30(4):1183-1190
Promiscuous mating systems provide the opportunity for females to bias fertilization toward particular males. However, distinguishing between male sperm competition and active female sperm choice is difficult for species with internal fertilization. Nevertheless, species that store and use sperm of different males in different storing structures and species where females are able to expel all or part of the ejaculates after copulation may be able to bias fertilization. We report a series of experiments aimed at providing evidence of female sperm choice in Euxesta eluta (Hendel), a species of ulidiid fly that expels and consumes ejaculates after copulation. We found no evidence of greater reproductive success for females mated singly, multiply with the same male, or mated multiply with different males. Female E. eluta possesses two spherical spermathecae and a bursa copulatrix for sperm storage, with a ventral receptacle. There was no significant difference in storing more sperm in spermathecae 24 h after copulation than immediately after copulation. Females mated with protein-fed males had greater reproductive success than similar females mated to protein-deprived males. Protein-fed females prevented to consume the ejaculate, retained more sperm when mated to protein-fed males than when mated to protein-deprived males. Our results suggest that female E. eluta can exert control of sperm retention of higher quality males through ejaculate ejection. 相似文献
18.
Gabriela Cardozo Alessandro Devigili Pietro Antonelli Andrea Pilastro 《Journal of evolutionary biology》2020,33(9):1294-1305
Males of many species evolved the capability of adjusting their ejaculate phenotype in response to social cues to match the expected mating conditions. When females store sperm for a prolonged time, the expected fitness return of plastic adjustments of ejaculate phenotype may depend on the interval between mating and fertilization. Although prolonged female sperm storage (FSS) increases the opportunity for sperm competition, as a consequence of the longer temporal overlap of ejaculates from several males, it may also create variable selective forces on ejaculate phenotype, for example by exposing trade‐offs between sperm velocity and sperm survival. We evaluated the relationship between the plasticity of ejaculate quality and FSS in the guppy, Poecilia reticulata, a polyandrous live‐bearing fish in which females store sperm for several months and where stored sperm contribute significantly to a male's lifelong reproductive success. In this species, males respond to the perception of future mating opportunities by increasing the quantity (number) and quality (swimming velocity) of ready‐to‐use sperm (an anticipatory response called ‘sperm priming’). Here we investigated (a) the effect of sperm priming on in vitro sperm viability at stripping and its temporal decline (as an estimate of sperm survival), and (b) the in vivo competitive fertilization success in relation to female sperm storage using artificial insemination. As expected, sperm‐primed males produced more numerous and faster sperm, but with a reduced in vitro sperm viability at stripping and after 4 hr, compared with their counterparts. Artificial insemination revealed that the small (nonsignificant) advantage of primed sperm when fertilization immediately follows insemination is reversed when eggs are fertilized by female‐stored sperm, weeks after insemination. By suggesting a plastic trade‐off between sperm velocity and viability, these results demonstrate that prolonged female sperm storage generates divergent selection pressures on ejaculate phenotype. 相似文献
19.
N. Wedell 《Journal of evolutionary biology》2001,14(5):746-754
Female mating rate is fundamental to evolutionary biology as it determines the pattern of sexual selection and sexual conflict. Despite its importance, the genetic basis for female remating rate is largely unknown and has only been demonstrated in one species. In paternally investing species there is often a conflict between the sexes over female mating rate, as females remate to obtain male nutrient donations and males try to prevent female remating to ensure high fertilization success. Butterflies produce two types of sperm: fertilizing, eupyrene sperm, and large numbers of nonfertile, apyrene sperm. The function of apyrene sperm in the polyandrous, paternally investing green‐veined white butterfly, Pieris napi, is to fill the female’s sperm storage organ thereby reducing her receptivity. However, there is large variation in number of apyrene sperm stored. Here, I examine the genetic basis to this variation, and if variation in number of apyrene sperm stored is related to females’ remating rate. The number of apyrene sperm stored at the time of remating has a genetic component and is correlated with female remating tendency, whereas no such relationship is found for fertilizing sperm. The duration of the nonreceptivity period in P. napi also has a genetic component and is inversely related to the degree of polyandry. Sexual conflict over female remating rate appears to be present in this species, with males using their apyrene sperm to exploit a female system designed to monitor sperm in storage. Ejaculates with a high proportion of nonfertile sperm may have evolved to induce females to store more of these sperm, thereby reducing remating. As a counter‐adaptation, females have evolved a better detection system to regain control over their remating rate. Sexually antagonistic co‐evolution of apyrene sperm number and female sperm storage may be responsible for ejaculates with predominantly nonfertile sperm in this butterfly. 相似文献
20.
Francesca Scolari Boaz Yuval Ludvik M Gomulski Marc F Schetelig Paolo Gabrieli Federico Bassetti Ernst A Wimmer Anna R Malacrida Giuliano Gasperi 《BMC genetics》2014,15(Z2):S10