Sperm competition promotes the exploitation of rival ejaculates

Hodgson, Dave; Hosken, David J.

doi:10.1016/j.jtbi.2006.06.024

Cited by 60 publications

(66 citation statements)

References 44 publications

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“…However, only recently have researchers begun to investigate nonsperm aspects of ejaculate allocation theoretically (36) and empirically (30,52,53). Moreover, the idea that males can potentially exploit the ejaculates of rival males is a recent one that has previously received only theoretical attention (3,4). Our results, together with previous studies (13), show that male D. melanogaster have the opportunity to exploit rival ejaculates.…”

Section: Resultssupporting

confidence: 58%

“…The ability to plastically adjust specific protein quantities in the ejaculate means that the costs to males of mating with previously inseminated females (e.g., sperm competition) may be partially ameliorated because of the second male's ability to exploit the effects of the previous male's Sfps. Thus, models of male reproductive investment (35,36) need to be reconsidered to take into account such reductions in costs to males mating with previously mated females (3,4).…”

Section: Resultsmentioning

confidence: 99%

“…strategic ejaculation | male accessory gland | sexual selection | intersexual interaction | reproduction F emale sexual promiscuity creates an arena for sperm competition and other forms of postcopulatory sexual selection (1,2). Promiscuity may also provide the opportunity for males to exploit the effects of rival males' ejaculates (3,4). This opportunity arises because, in many species, the ejaculate not only is essential for fertilization but also can influence female postmating behavior and physiology in ways that promote male reproductive success.…”

mentioning

confidence: 99%

“…For example, Hodgson and Hosken (4) argue that if the ejaculate of the first male to mate with a female improves sperm survival within the female's reproductive tract, males mating with recently mated females could benefit through both increased sperm survival and decreased investment in the ejaculate components causing this effect. Similarly, game theoretic analyses predict that, under certain conditions, males mating with recently mated females should exploit the fecundity-stimulating effects of a previous male's ejaculate (3).…”

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confidence: 99%

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Protein-specific manipulation of ejaculate composition in response to female mating status in Drosophila melanogaster

Sirot

Wolfner

Wigby

2011

Proc. Natl. Acad. Sci. U.S.A.

165

173

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Female promiscuity can generate postcopulatory competition among males, but it also provides the opportunity for exploitation of rival male ejaculates. For example, in many insect species, male seminal fluid proteins (Sfps) transferred in a female's first mating stimulate increased fecundity and decreased receptivity to remating. Subsequent mates of females could potentially take advantage of the effects of the first male's Sfps and strategically reduce investment in their own ejaculate. We compared postmating responses (fecundity and sexual receptivity) of Drosophila melanogaster females after their first (virgin) matings (V), to the responses of females remating (M) 24 h after their first mating. The results show that M matings fail to boost fecundity and, thus, males are unlikely to gain fitness from transferring Sfps whose sole function-in V matings-is fecundity-stimulation. However, males can protect their likelihood of paternity in M matings through the transfer of receptivity-inhibiting Sfps. The levels of a fecundity-stimulating Sfp (ovulin) were significantly lower in M females relative to V females, at the same time point shortly after the end of mating. In contrast, the levels of a key receptivityinhibiting Sfp (sex peptide) were the same in M and V females. These results support the hypothesis that males can adaptively tailor the composition of proteins in the ejaculate, allowing a male to take advantage of the fecundity-stimulating effects of the previous male's ovulin, yet maintaining investment in sex peptide. Furthermore, our results demonstrate sophisticated protein-specific ejaculate manipulation. strategic ejaculation | male accessory gland | sexual selection | intersexual interaction | reproduction F emale sexual promiscuity creates an arena for sperm competition and other forms of postcopulatory sexual selection (1, 2). Promiscuity may also provide the opportunity for males to exploit the effects of rival males' ejaculates (3, 4). This opportunity arises because, in many species, the ejaculate not only is essential for fertilization but also can influence female postmating behavior and physiology in ways that promote male reproductive success. For example, in insects, products of the male accessory glands can have a variety of effects in the mated female, including stimulating fecundity, promoting sperm storage, and inhibiting receptivity to remating (reviewed in refs. 5-8). In mammals, functions of seminal fluids in the mated female can include stimulating ovulation, promoting sperm motility, mediating sperm storage, and protecting sperm through suppression of immune defense (9, 10; reviewed in ref. 11). If these maleinduced effects persist beyond the time by which a female remates, then her next mate could exploit the effects of her earlier mates' ejaculates. A male could thereby reduce his own mating costs by decreasing investment in particular components of his own ejaculate.Recently developed theoretical models make specific predictions about ejaculate exploitation. For example, Hodgson...

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Section: Resultssupporting

confidence: 58%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Protein-specific manipulation of ejaculate composition in response to female mating status in Drosophila melanogaster

Sirot

Wolfner

Wigby

2011

Proc. Natl. Acad. Sci. U.S.A.

165

173

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“…In particular, because it is the ejaculate that is at the frontline of competition, extensive attention has been devoted to modeling how sperm competition influences rates of sperm production, the quality of sperm, and male expenditure on the ejaculate under various competitive scenarios. However, sperm are, but one part of the ejaculate and recent theoretical attention has been devoted to understanding how sperm competition shapes male investment in the non-sperm component of the ejaculate, the seminal fluid (Hodgson & Hosken 2006, Cameron et al 2007, Alonzo & Pizzari 2010, Fromhage 2012. The aim of this review is to provide a broad overview of adaptations in male ejaculate biology that are thought to have arisen as evolutionary consequences of the war between males for gaining fertilizations.…”

Section: Introductionmentioning

confidence: 99%

Sperm wars and the evolution of male fertility

Simmons¹,

Fitzpatrick²

2012

Reproduction

306

343

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Females frequently mate with several males, whose sperm then compete to fertilize available ova. Sperm competition represents a potent selective force that is expected to shape male expenditure on the ejaculate. Here, we review empirical data that illustrate the evolutionary consequences of sperm competition. Sperm competition favors the evolution of increased testes size and sperm production. In some species, males appear capable of adjusting the number of sperm ejaculated, depending on the perceived levels of sperm competition. Selection is also expected to act on sperm form and function, although the evidence for this remains equivocal. Comparative studies suggest that sperm length and swimming speed may increase in response to selection from sperm competition. However, the mechanisms driving this pattern remain unclear. Evidence that sperm length influences sperm swimming speed is mixed and fertilization trials performed across a broad range of species demonstrate inconsistent relationships between sperm form and function. This ambiguity may in part reflect the important role that seminal fluid proteins (sfps) play in affecting sperm function. There is good evidence that sfps are subject to selection from sperm competition, and recent work is pointing to an ability of males to adjust their seminal fluid chemistry in response to sperm competition from rival males. We argue that future research must consider sperm and seminal fluid components of the ejaculate as a functional unity. Research at the genomic level will identify the genes that ultimately control male fertility.

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Condition‐dependent ejaculate production affects male mating behavior in the common bedbugCimex lectularius

Kaldun

Otti

2016

Ecology and Evolution

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Food availability in the environment is often low and variable, constraining organisms in their resource allocation to different life‐history traits. For example, variation in food availability is likely to induce condition‐dependent investment in reproduction. Further, diet has been shown to affect ejaculate size, composition and quality. How these effects translate into male reproductive success or change male mating behavior is still largely unknown. Here, we concentrated on the effect of meal size on ejaculate production, male reproductive success and mating behavior in the common bedbug Cimex lectularius. We analyzed the production of sperm and seminal fluid within three different feeding regimes in six different populations. Males receiving large meals produced significantly more sperm and seminal fluid than males receiving small meals or no meals at all. While such condition‐dependent ejaculate production did not affect the number of offspring produced after a single mating, food‐restricted males could perform significantly fewer matings than fully fed males. Therefore, in a multiple mating context food‐restricted males paid a fitness cost and might have to adjust their mating strategy according to the ejaculate available to them. Our results indicate that meal size has no direct effect on ejaculate quality, but food availability forces a condition‐dependent mating rate on males. Environmental variation translating into variation in male reproductive traits reveals that natural selection can interact with sexual selection and shape reproductive traits. As males can modulate their ejaculate size depending on the mating situation, future studies are needed to elucidate whether environmental variation affecting the amount of ejaculate available might induce different mating strategies.

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Sperm competition promotes the exploitation of rival ejaculates

Cited by 60 publications

References 44 publications

Protein-specific manipulation of ejaculate composition in response to female mating status in Drosophila melanogaster

Protein-specific manipulation of ejaculate composition in response to female mating status in Drosophila melanogaster

Sperm wars and the evolution of male fertility

Condition‐dependent ejaculate production affects male mating behavior in the common bedbugCimex lectularius

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