Sperm Competition Games: External Fertilization and “Adapative” Infertility

Ball, Michael; Parker, G. A.

doi:10.1006/jtbi.1996.0090

Cited by 142 publications

(134 citation statements)

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“…Additionally the dominant males show the most rapid decrease in sperm speed in ovarian fluid through our 40 s observational period. In accordance with theoretical models (Parker, 1970(Parker, , 1998Ball and Parker, 1996;Parker et al, 2013), sperm from males mating in disfavored roles tend to have higher velocity in water than the sperm from males mating in favored reproductive roles. This difference in sperm velocity between dominant and subordinate males is mainly manifested in the initial period after activation and in water only.…”

Section: Discussionsupporting

confidence: 74%

“…This behavior often results in sperm competition where sperm from two or more males co-occur at the site of fertilization (Parker, 1970;Simmons, 2005). When there is risk of sperm competition, males may produce more sperm, larger sperm or sperm that have higher velocity than would be required to fertilize the eggs in absence of competition, at least in theory (Parker, 1970(Parker, , 1998Ball and Parker, 1996). Recent empirical studies have, in line with theory, also shown that increased risk of sperm competition leads to a higher investment in sperm velocity (Burness et al, 2004;Rudolfsen et al, 2006) and that such sperm velocity increases may be important for fertilization success (Levitan, 2000;Al-Qarawi et al, 2002;Kupriyanova and Havenhand, 2002;Gage et al, 2004;Liljedal, 2005;Schulte-Hostedde and Burness, 2005;Egeland et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

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Status Specific Tailoring of Sperm Behavior in an External Fertilizer

et al. 2016

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Why dominant males experiencing intense sperm competition sometimes show low investments in sperm production is not always obvious. One well-documented example is that of the external fertilizing teleost, the Arctic charr (Salvelinus alpinus), where individuals becoming dominant reduce sperm production and sperm swimming speed in water compared to subordinates. Here, we report how ovarian fluid differentially influences sperm velocity of dominant and subordinate male Arctic charr. That is, sperm from dominant males increase their velocity in water diluted ovarian fluid compared to that observed in water, while sperm from subordinates, on the other hand, decrease velocity in ovarian fluid compared to that observed in water. Thus, subordinates, who invest more resources in their sperm and usually show the highest sperm velocity in water, have lower gains from their investment than dominant males when sperm are swimming in ovarian fluid. In sum, our result suggests that ovarian fluid increase sperm velocity more in dominant males than in subordinate males. Although this finding could partly be caused by cryptic female choice exerted by the ovarian fluid for sperm from dominant males, an alternative and more parsimonious explanation is that sperm from dominant males may simply be better designed for swimming in ovarian fluid compared to sperm from subordinate males. Thus, sperm production in the two reproductive roles seems to be adaptively tailored to different external environments.

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Section: Discussionsupporting

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Status Specific Tailoring of Sperm Behavior in an External Fertilizer

et al. 2016

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“…Because local density is a good indicator of the likely sperm environment, animals in highdensity environments are most likely to face polyspermyinducing sperm concentrations and seem to be producing sperm that are less likely to induce polyspermy. In external fertilizers with (relatively) fast blocks to polyspermy, faster sperm are predicted to have an advantage at finding unfertilized eggs (26,28,54,55); however, high-velocity sperm may also be more likely to induce polyspermy (42). Although we were unable to directly measure sperm velocity, velocity is expected to trade off against longevity (6,26,55; but see 29,56).…”

Section: Discussionmentioning

confidence: 99%

Gamete plasticity in a broadcast spawning marine invertebrate

Crean

Marshall

2008

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

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Sperm competition has classically been thought to maintain anisogamy (large eggs and smaller sperm) because males are thought to maximize their chance of winning fertilizations by trading sperm size for number. More recently it has been recognized that sperm quality (e.g., size, velocity) can also influence sperm competition, although studies have yielded conflicting results. Because sex evolved in the sea, debate has continued over the role of sperm competition and sperm environment in determining both sperm and egg size in externally fertilizing broadcast spawners. Remarkably, however, there have been no direct tests of whether broadcast spawners change the traits of their gametes depending on the likelihood of sperm competition. We manipulated the density (and thus, sperm environment) of a broadcast spawning ascidian (Styela plicata) in the field and then determined whether the phenotype of eggs and sperm changed. We found that sperm from adults kept at high density were larger and more motile than sperm from low-density adults. In vitro fertilizations revealed that sperm from high-density adults also lived longer and induced less polyspermy. Adult density also affected egg traits: eggs from high-density adults were smaller targets for sperm overall but produced larger ovicells than eggs from low-density adults. This suggests that broadcast spawning mothers balance (potentially conflicting) pre-and postzygotic selection pressures on egg size. Overall, our results suggest that sperm competition does not represent a strong force maintaining anisogamy in broadcast spawners. Instead, sperm limitation seems to select for large eggs and smaller, more numerous sperm.anisogamy ͉ sperm competition ͉ adaptive maternal effect ͉ transgenerational plasticity T he fundamental difference between the sexes is that males produce numerous, tiny sperm, and females produce relatively fewer, large eggs (anisogamy). Classic theory suggests that anisogamy most likely evolved by, and is maintained through, sperm competition (whereby sperm from 2 or more males compete to fertilize an egg) because males producing a greater number of sperm have a competitive advantage (refs. 1 and 2; but see ref. 3 for an alternative). In species with internal fertilization, competition for fertilizations can therefore be viewed as a ''raffle,'' whereby males that have the highest representation of sperm in the pool have the greatest chance of fertilizing eggs (4, 5). More recently, however, it has been proposed that sperm quality (e.g., sperm size, velocity, and longevity) can also influence the outcome of sperm competition (6, 7). Furthermore, because a male's sperm supply is limited (8, 9) and each mating opportunity may carry a variable risk of sperm competition (10), males must make decisions on the optimal allocation of both sperm number and quality for each mating event. The optimal allocation of sperm size and number within an ejaculate remains a source of intense debate (reviewed in refs. 7 and 9).The prediction that males should increase the ...

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“…An explanation is that sexual selection and sperm competition have driven males to eject sperm close to, or even into females; sperm are no longer constrained by the need to maintain themselves in the way that the hologametes of a hypothetical isogametic unicellular ancestor would have been. Under internal fertilization, sperm are often provisioned by agents in the female tract, and under external fertilization such as simultaneous spawning, sperm competition places a premium on high sperm motility and low survival where the two components trade-off against each other (Ball & Parker 1996), so that sperm life may be very short. All of these effects allow sperm to become smaller by shifting g 1 (m 1 ) to the left of our hypothetical ancestral state.…”

Section: Discussionmentioning

confidence: 99%

The evolution of anisogamy: a game-theoretic approach

Bulmer¹,

Parker

2002

Proc. R. Soc. Lond. B

106

169

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A popular theory has proposed that anisogamy originated through disruptive selection acting on an ancestral isogamous population, though recent work has emphasized the importance of other factors in its evolution. We re-examine the disruptive selection theory, starting from an isogamous population with two mating types and taking into account the functional relationship, g(m), between the fitness of a gamete and its size, m, as well as the relationship, f(S ), between the fitness of a zygote and its size, S. Evolutionary game theory is used to determine the existence and continuous stability of isogamous and anisogamous strategies for the two mating types under various models for the two functions g(m) and f(S ). In the ancestral unicellular state, these two functions are likely to have been similar; this leads to isogamy whether they are sigmoidal or concave, though in the latter case allowance must be made for a minimal gamete size. The development of multicellularity may leave g(m) relatively unchanged while f(S ) moves to the right, leading to the evolution of anisogamy. Thus, the disruptive selection theory provides a powerful explanation of the origin of anisogamy, though other selective forces may have been involved in the subsequent specialization of micro-and macrogametes.

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Sperm Competition Games: External Fertilization and “Adapative” Infertility

Cited by 142 publications

References 0 publications

Status Specific Tailoring of Sperm Behavior in an External Fertilizer

Status Specific Tailoring of Sperm Behavior in an External Fertilizer

Gamete plasticity in a broadcast spawning marine invertebrate

The evolution of anisogamy: a game-theoretic approach

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