共查询到20条相似文献,搜索用时 0 毫秒
1.
K. E. ELGEE J. P. EVANS I. W. RAMNARINE S. A. RUSH T. E. PITCHER 《Journal of evolutionary biology》2010,23(6):1331-1338
Guppies (Poecilia reticulata) are models for understanding the interplay between natural and sexual selection. In particular, predation has been implicated as a major force affecting female sexual preferences, male mating tactics and the level of sperm competition. When predation is high, females typically reduce their preferences for showy males and engage more in antipredator behaviours, whereas males exploit these changes by switching from sexual displays to forced matings. These patterns are thought to account for the relatively high levels of multiple paternity in high‐predation populations compared to low‐predation populations. Here, we assess the possible evolutionary consequences of these patterns by asking whether variation in sperm traits reflect differences in predation intensity among four pairs of Trinidadian populations: four that experience relatively low levels of predation from a gape‐limited predator and four that experience relatively high levels of predation from a variety of piscivores. We found that males in high‐predation populations had faster swimming sperm with longer midpieces compared to males in low‐predation populations. However, we found no differences among males in high‐ and low‐predation populations with respect to sperm number, sperm head length, flagellum length and total sperm length. 相似文献
2.
Paternity in mallards: effects of sperm quality and female sperm selection for inbreeding avoidance 总被引:5,自引:0,他引:5
Denk Angelika G.; Holzmann Alois; Peters Anne; Vermeirssen Etienne L.M.; Kempenaers Bart 《Behavioral ecology》2005,16(5):825-833
Postcopulatory processes might play an important role in sexualselection. In theory, fertilization success could be controlledby females via selection of particular sperm within their reproductivetract, or it could be determined by sperm competition per se.In practice, these two mechanisms are difficult to disentangle.To assess the relative importance of both mechanisms we usedartificial insemination in combination with measurements ofsperm quality (swimming speed and motility) in mallards. Inthis species, females often lack behavioral control over copulationsand hence may use postcopulatory mechanisms to optimize theirreproductive output. One important factor affecting female fitnessmay be selection of genetically compatible males. To investigatethe influence of sperm quality and parental relatedness on paternitywe inseminated 12 groups of related females with a sperm mixturecontaining equal numbers of sperm from a brother and from anunrelated male. Paternity was independent of the relatednessof the siring male to the female but was significantly affectedby long-term sperm swimming speed and motility. No interactionbetween relatedness and sperm quality on paternity was observed.These results suggest that female mallards are not able to selectsperm on a purely genetic basis and emphasize the importanceof sperm quality in gaining paternity. 相似文献
3.
Recent studies in a variety of species have shown that polyandrous females are somehow able to bias paternity against their relatives postcopulation, although how they do so remains unknown. Field crickets readily mate with their siblings, but when also mated to an unrelated male, they produce disproportionately fewer inbred offspring. We use a new competitive microsatellite polymerase chain reaction technique to determine the contribution of males to stored sperm and subsequent paternity of offspring. Paternity is almost completely predicted by how much sperm from a particular male is stored, and unrelated males contribute more sperm to storage and have a corresponding higher paternity success. 相似文献
4.
5.
Multiple paternity in reptiles: patterns and processes 总被引:2,自引:2,他引:2
The evolution of female promiscuity poses an intriguing problem as benefits of mating with multiple males often have to arise via indirect, genetic, effects. Studies on birds have documented that multiple paternity is common in natural populations but strong evidence for selection via female benefits is lacking. In an attempt to evaluate the evidence more broadly, we review studies of multiple paternity in natural populations of all major groups of nonavian reptiles. Multiple paternity has been documented in all species investigated so far and commonly exists in over 50% of clutches, with particularly high levels in snakes and lizards. Marine turtles and lizards with prolonged pair-bonding have relatively low levels of multiple paternity but levels are nevertheless higher than in many vertebrates with parental care. There is no evidence that high levels of polyandry are driven by direct benefits to females and the evidence that multiple paternity arises from indirect genetic benefits is weak. Instead, we argue that the most parsimonious explanation for patterns of multiple paternity is that it represents the combined effect of mate-encounter frequency and conflict over mating rates between males and females driven by large male benefits and relatively small female costs, with only weak selection via indirect benefits. A crucial step for researchers is to move from correlative approaches to experimental tests of assumptions and predictions of theory under natural settings, using a combination of molecular techniques and behavioural observations. 相似文献
6.
Darren James Parker Julia Zaborowska Michael Gordon Ritchie Karim Vahed 《Molecular ecology》2017,26(11):3050-3061
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. 相似文献
7.
In guppies (Poecilia reticulata) precopulatory sexual selection (via female choice) and post-copulatory selection (via sperm competition) both favour males with relatively high levels of carotenoid (orange) pigmentation, suggesting that colourful males produce more competitive ejaculates. Here we test whether there is a positive association between male orange pigmentation and sperm quality. Our analysis of sperm quality focused on sperm swimming speeds (using CASA: computer-assisted sperm analysis to estimate three parameters of sperm velocity in vitro), sperm viability (proportion of live sperm per stripped ejaculate) and sperm lengths. We found that males with relatively large areas of orange pigmentation had significantly faster and more viable sperm than their less ornamented counterparts, suggesting a possible link between dietary carotenoid intake and sperm quality. By contrast, we found no relationship between sperm length (head length and total sperm length) and male phenotype. These findings, in conjunction with previous work showing that highly ornamented male guppies sire higher quality offspring, suggest that female preference for colourful males and sperm competition work in concert to favour intrinsically higher quality males. 相似文献
8.
Males of many animals perform ‘copulatory courtship’ during copulation, but the possible reproductive significance of this behaviour has seldom been investigated. In some animals, including the spider Physocyclus globosus (Pholcidae), the female discards sperm during or immediately following some copulations. In this study, we determined which of several variables associated with copulation correlated with paternity success in P. globosus when two males mate with a single female. Then, by determining which of these variables also correlated with sperm dumping, we inferred which variables may affect paternity via the mechanism of sperm dumping. Male abdomen vibration (a copulatory courtship behaviour) and male genitalic squeezing both correlated with both paternity and sperm dumping; so, these traits may be favoured by biased sperm dumping. Biased sperm dumping may also be the mechanism by which possible cryptic female choice favours another male trait that was the subject of a previous study, responsiveness to female stridulation. 相似文献
9.
Sperm competition and cryptic female choice profoundly affect sperm morphology, producing diversity within both species and individuals. One type of within-individual sperm variation is sperm heteromorphism, in which each male produces two or more distinct types of sperm simultaneously, only one of which is typically fertile (the "eusperm"). The adaptive significance of nonfertile "parasperm" types is poorly understood, although numerous sperm-heteromorphic species are known from many disparate taxa. This paper examines in detail two female-centred hypotheses for the evolution and maintenance of this unconventional sperm production strategy. First, we use game theoretical models to establish that parasperm may function to protect eusperm from female-generated spermicide, and to elucidate the predictions of this idea. Second, we expand on the relatively undeveloped idea that parasperm are used by females as a criterion for cryptic female choice, and discuss the predictions generated by this idea compared to other hypotheses proposed to explain sperm heteromorphism. We critically evaluate both hypotheses, suggest ways in which they could be tested, and propose taxa in which they could be important. 相似文献
10.
Jonathan P. Evans Patrice Rosengrave Clelia Gasparini Neil J. Gemmell 《Proceedings. Biological sciences / The Royal Society》2013,280(1772)
Disentangling the relative roles of males, females and their interactive effects on competitive fertilization success remains a challenge in sperm competition. In this study, we apply a novel experimental framework to an ideally suited externally fertilizing model system in order to delineate these roles. We focus on the chinook salmon, Oncorhynchus tshawytscha, a species in which ovarian fluid (OF) has been implicated as a potential arbiter of cryptic female choice for genetically compatible mates. We evaluated this predicted sexually selected function of OF using a series of factorial competitive fertilization trials. Our design involved a series of 10 factorial crosses, each involving two ‘focal’ rival males whose sperm competed against those from a single ‘standardized’ (non-focal) rival for a genetically uniform set of eggs in the presence of OF from two focal females. This design enabled us to attribute variation in competitive fertilization success among focal males, females (OF) and their interacting effects, while controlling for variation attributable to differences in the sperm competitive ability of rival males, and male-by-female genotypic interactions. Using this experimental framework, we found that variation in sperm competitiveness could be attributed exclusively to differences in the sperm competitive ability of focal males, a conclusion supported by subsequent analyses revealing that variation in sperm swimming velocity predicts paternity success. Together, these findings provide evidence that variation in paternity success can be attributed to intrinsic differences in the sperm competitive ability of rival males, and reveal that sperm swimming velocity is a key target of sexual selection. 相似文献
11.
Dara N. Orbach Anna C. Rooke Jonathan P. Evans Trevor E. Pitcher Craig F. Purchase 《Journal of evolutionary biology》2020,33(4):449-459
In species with limited opportunities for pre‐ejaculatory sexual selection (behavioural components), post‐ejaculatory mechanisms may provide opportunities for mate choice after gametes have been released. Recent evidence from a range of taxa has revealed that cryptic female choice (i.e., female‐mediated differential fertilization bias), through chemical cues released with or from eggs, can differentially regulate the swimming characteristics of sperm from various males and ultimately determine male fertilization success under sperm competition. We assessed the potential role that such female‐modulated chemical cues play in influencing sperm swimming characteristics in beach‐spawning capelin (Mallotus villosus), an externally fertilizing fish that mates as couples (one male and one female) or threesomes (two males and one female) with presumably limited opportunities for pre‐ejaculatory sexual selection. We assayed sperm swimming characteristics under varying doses and donor origins of egg cues and also examined the possibility of assortative mating based on body size. We found mating groups were not associated by size, larger males did not produce better quality ejaculates, and egg cues (regardless of dosage or donor identity) did not influence sperm swimming characteristics. Our findings suggest that intersexual pre‐ejaculatory sexual selection and cryptic female choice mediated by female chemical cues are poorly developed in capelin, possibly due to unique natural selection constraints on reproduction. 相似文献
12.
In spite of considerable interest in postcopulatory sexual selection, separating the effects of sperm competition from cryptic female choice remains difficult because mechanisms underlying postcopulatory processes are poorly understood. One methodological challenge is to quantify insemination success for individual males within the sperm stores of multiply mated females to discover how insemination translates into eventual paternity. Any proposed method must be applicable in organisms without extensive DNA sequence information (which include the majority of model species for sexual selection). Here, we describe the development and application of microsatellite competitive-multiplex-PCR for quantifying relative contributions to a small number of sperm in storage. We studied how DNA template characteristics affect PCR amplification of known concentrations of mixed DNA and generated regressions for correcting observations of allelic signal strength based on such characteristics. We used these methods to examine patterns of sperm storage in twice-mated female yellow dung flies, Scathophaga stercoraria. We confirm previous findings supporting sperm displacement and demonstrate that average paternity for the last mate accords with the mean proportion of sperm stored. We further find consistent skew in storage across spermathecae, with more last male sperm stored in the singlet spermatheca on one side of the body than in the doublet on the opposite side. We also show that the time between copulations may be important for effectively sorting sperm. Finally, we demonstrate that male size may influence the opportunity for sperm choice, suggesting future work to disentangle the roles of male competition and cryptic female choice. 相似文献
13.
Simmons Leigh W.; Wernham Julie; Garcia-Gonzalez Francisco; Kamien Dan 《Behavioral ecology》2003,14(4):539-545
Recent attention has focused on the role that sperm competitionmay play in the evolution of sperm morphology. Theoretical analysespredict increased sperm size, decreased sperm size, and no changein sperm size in response to sperm competition, depending onthe assumptions made concerning the life history and functionof sperm. However, although there is good evidence that spermmorphology varies widely within and between species, the adaptivesignificance of this variation has not been examined. Here wedocument significant intraspecific variation in sperm lengthin the field cricket, Teleogryllus oceanicus. Sperm length didnot influence the rate of migration of sperm from the spermatophoreto the female's spermatheca. We performed sperm competitiontrials in which we varied the numbers of sperm transferred byeach of two males that differed in the length of sperm theyproduced. Neither sperm length nor the number of sperm transferredinfluenced paternity. The same results were obtained using twodifferent methods for assigning paternity. The distributionof paternity across a female's mates was highly variable, withfrequently one, or more in the case of females mated to fourmales, principal sire. There were no mating order effects onpaternity. These data show that sperm do not mix randomly inthe female's spermatheca. We discuss several alternative explanationsfor the patterns of paternity observed. 相似文献
14.
Sperm competition can produce fascinating adaptations with far-reaching evolutionary consequences. Social taxa make particularly interesting models, because the outcome of sexual selection determines the genetic composition of groups, with attendant sociobiological consequences. Here, we use molecular tools to uncover some of the mechanisms and consequences of sperm competition in the leaf-cutting ant Atta colombica, a species with extreme worker size polymorphism. Competitive PCR allowed quantification of the relative numbers of sperm stored by queens from different males, and offspring genotyping revealed how sperm number translated into paternity of eggs and adult workers. We demonstrate that fertilization success is directly related to sperm numbers, that stored sperm are well-mixed and that egg paternity is constant over time. Moreover, worker size was found to have a considerable genetic component, despite expectations that genetic effects on caste fate should be minor in species with a low degree of polyandry. Our data suggest that sexual conflict over paternity is largely resolved by the lifetime commitment between mates generated by long-term sperm storage, and show that genetic variation for caste can persist in societies with comparatively high relatedness. 相似文献
15.
Studies of fertilization success have demonstrated that maleeffects are often a strong and important source of variationin P2 (the proportion of offspring that are fertilized by thesecond male to mate). More recently there has been emphasison female processes that occur during and after copulation thatmight bias the outcome of male-male interactions. Here we usedthe sterile male technique to evaluate whether female genitalmorphology influences the repeatability of P2 when the samepair of male dung beetles, Onthophagus taurus, copulated witha series of full-sib females or unrelated females that wereall unrelated to the male pair. Repeatability estimates of measuresof female genital morphology showed that full-sib females variedless in their genital morphology than did unrelated females.Therefore, if female genital traits are an important sourceof variation in male fertilization success, P2 should be morerepeatable across full-sib than unrelated females. Contraryto this prediction, we show that the repeatability of P2 didnot differ between female groups. Moreover, specific dimensionsof the female genitalia (sclerotized vagina and bursa) did notcontribute significantly to variance in P2. In contrast, maleeffects had consistent and repeatable influences on paternityacross females. These were partly explained by variation inthe morphology of male genital sclerites. 相似文献
16.
Males with high genetic similarity to females sire more offspring in sperm competition in Peron's tree frog Litoria peronii 总被引:1,自引:0,他引:1
Sherman CD Wapstra E Uller T Olsson M 《Proceedings. Biological sciences / The Royal Society》2008,275(1637):971-978
Recent work has confirmed that genetic compatibility among mates can be an important determinant of siring success in sperm competition experiments and in free-ranging populations. Most of this work points towards mate choice of less related mates. However, there may also be the potential for mate choice for intermediate or even genetically similar mates to prevent outbreeding depression or hybridization with closely related taxa. We studied relatedness effects on post-copulatory gametic choice and/or sperm competition in an external fertilizer, Peron's tree frog (Litoria peronii), since external fertilizers offer exceptional control in order to test gametic interaction effects on probability of paternity and zygote viability. Sperm competition experiments were done blindly with respect to genetic relatedness among males and females. Thereafter, paternity of offspring was assigned using eight microsatellite loci. Three hybridization trials between L. peronii and a closely related sympatric species Litoria tyleri were also carried out. In the sperm competition trials, males that are more genetically similar to the female achieved higher siring success compared with less genetically similar males. The hybridization trials confirmed that the two species can interbreed and we suggest that the risk of hybridization may contribute to selection benefits for genetically more similar males at fertilization. To our knowledge, this study is the first to show evidence for post-copulatory selection of sperm from genetically more similar individuals within a natural population. 相似文献
17.
Odonates were the first group of organisms where sperm competition and last male sperm precedence have been identified. With the development of 10 microsatellites for the emperor dragonfly Anax imperator, the function and priority patterns of the multiple sperm storage organs of females can be studied and compared between species in natural populations. In addition, two microsatellite loci developed for the sister species Anax parthenope, are also highly polymorphic in A. imperator. For the presented 12 microsatellite loci, the number of alleles per locus ranged from two to 24. Observed heterozygosity ranged from 0.07 to 0.88. 相似文献
18.
Oviduct length was measured in 48 species representing 33 genera of mammals in order to examine possible relationships between female morphology and the occurrence of sperm competition due to matings with multiple males. Multiple regression analyses revealed that residuals of oviduct length were positively correlated both with residuals of testes weight and with sperm midpiece volume in the genera and species studied. These correlations remained significant after application of comparative analysis of independent contrasts to control for possible phylogenetic biases in the data set. These results indicate that sexual selection (relating to sperm competition and cryptic female choice) has influenced co-evolution of oviduct length, testes size and sperm morphology in mammals. 相似文献
19.
Milan ?ezá? 《Proceedings. Biological sciences / The Royal Society》2009,276(1668):2697-2701
The males of invertebrates from a few phyla, including arthropods, have been reported to practise traumatic insemination (TI; i.e. injecting sperm by using the copulatory organ to penetrate the female''s body wall). As all previously reported arthropod examples have been insects, there is considerable interest in whether TI might have evolved independently in other arthropods. The research reported here demonstrates the first case of TI in the arthropod subphylum Chelicerata, in particular how the genital morphology and mating behaviour of Harpactea sadistica (Řezáč 2008), a spider from Israel, has become adapted specifically for reproduction based on TI. Males have needle-like intromittent organs and females have atrophied spermathecae. In other spiders, eggs are fertilized simultaneously with oviposition, but the eggs of H. sadistica are fertilized in the ovaries (internal fertilization) and develop as embryos before being laid. Sperm-storage organs of phylogenetically basal groups to H. sadistica provide males with last male sperm priority and allow removal of sperm by males that mate later, suggesting that TI might have evolved as an adaptive strategy to circumvent an unfavourable structure of the sperm-storage organs, allowing the first male to mate with paternity advantage. Understanding the functional significance of TI gives us insight into factors underlying the evolution of the genital and sperm-storage morphology in spiders. 相似文献
20.
Jones Theresa M.; Featherston Rebecca; Paris Damien B.B.P.; Elgar Mark A. 《Behavioral ecology》2007,18(1):251-258
The influence of male age on reproductive success after a singlemating has been explored widely; however, few studies have investigatedwhether quantitative or qualitative differences in male spermare responsible for the observed patterns. Moreover, the roleof male age on sperm competitive ability has been largely ignored.We examined the importance of male age on the probability andamount of sperm transferred during a single mating and exploredwhether sperm competitive ability varies with male age in thehide beetle Dermestes maculatus, a species where sperm viabilitydoes not vary with male age. We also investigated whether spermtransfer rates varied with female age. We found that the probabilityof sperm transfer and the amount of sperm transferred variedwith male, but not female, age. All males performed behaviorallysuccessful copulations, but intermediate-age and old males weremore likely to transfer sperm successfully and also transferreda greater quantity of sperm than young males. Old males wereless likely to transfer sperm than intermediate-age males, butif they did transfer sperm successfully, they transferred comparableamounts. Sperm competitive ability varied with male age andreflected the quantity of sperm transferred. On average, intermediate-agemales achieved greater fertilization success when competingagainst young or old males than when competing against otherintermediate-age males. Old males were poor competitors againstintermediate-age males, but they achieved significantly higherrates of fertilization when competing against young males. Ourfindings suggest that quantitative differences in the amountof sperm transferred determine male success in sperm competitionin the hide beetle. 相似文献