The Experts below are selected from a list of 6057 Experts worldwide ranked by ideXlab platform
Leigh W Simmons - One of the best experts on this subject based on the ideXlab platform.
-
additive genetic variance in Polyandry enables its evolution but Polyandry is unlikely to evolve through sexy or good sperm processes
Journal of Evolutionary Biology, 2016Co-Authors: Laura M. Travers, Leigh W Simmons, Francisco GarciagonzalezAbstract:: Polyandry is widespread despite its costs. The sexually selected sperm hypotheses ('sexy' and 'good' sperm) posit that sperm competition plays a role in the evolution of Polyandry. Two poorly studied assumptions of these hypotheses are the presence of additive genetic variance in Polyandry and sperm competitiveness. Using a quantitative genetic breeding design in a natural population of Drosophila melanogaster, we first established the potential for Polyandry to respond to selection. We then investigated whether Polyandry can evolve through sexually selected sperm processes. We measured lifetime Polyandry and offensive sperm competitiveness (P2 ) while controlling for sampling variance due to male × male × female interactions. We also measured additive genetic variance in egg-to-adult viability and controlled for its effect on P2 estimates. Female lifetime Polyandry showed significant and substantial additive genetic variance and evolvability. In contrast, we found little genetic variance or evolvability in P2 or egg-to-adult viability. Additive genetic variance in Polyandry highlights its potential to respond to selection. However, the low levels of genetic variance in sperm competitiveness suggest that the evolution of Polyandry may not be driven by sexy sperm or good sperm processes.
-
Polyandry as a mediator of sexual selection before and after mating
Philosophical Transactions of the Royal Society B, 2013Co-Authors: Charlotta Kvarnemo, Leigh W SimmonsAbstract:The Darwin–Bateman paradigm recognizes competition among males for access to multiple mates as the main driver of sexual selection. Increasingly, however, females are also being found to benefit from multiple mating so that Polyandry can generate competition among females for access to multiple males, and impose sexual selection on female traits that influence their mating success. Polyandry can reduce a male's ability to monopolize females, and thus weaken male focused sexual selection. Perhaps the most important effect of Polyandry on males arises because of sperm competition and cryptic female choice. Polyandry favours increased male ejaculate expenditure that can affect sexual selection on males by reducing their potential reproductive rate. Moreover, sexual selection after mating can ameliorate or exaggerate sexual selection before mating. Currently, estimates of sexual selection intensity rely heavily on measures of male mating success, but Polyandry now raises serious questions over the validity of such approaches. Future work must take into account both pre- and post-copulatory episodes of selection. A change in focus from the products of sexual selection expected in males, to less obvious traits in females, such as sensory perception, is likely to reveal a greater role of sexual selection in female evolution.
-
the evolution of Polyandry sperm competition sperm selection and offspring viability
Annual Review of Ecology Evolution and Systematics, 2005Co-Authors: Leigh W SimmonsAbstract:▪ Abstract In contrast to Bateman's principle, there is now increasing evidence that female fitness can depend on the number of mates obtained. A number of genetic benefits have been proposed for the evolution of Polyandry. A meta-analysis of available data suggests that Polyandry, rather than multiple mating, can have a weak but significant general effect on embryo viability, as indicated by egg hatching success. Although this effect is generally regarded as evidence in favor of the genetic incompatibility hypothesis, appropriate data that test for intrinsic sire effects on embryo viability are generally unavailable. Moreover, maternal effects that could generate the result have not been adequately controlled, and there is little unequivocal evidence to suggest that fertilization is biased toward sperm bearing genotypes that would enhance offspring viability. Greater effort is required in these areas to elucidate the mechanisms underlying observed fitness effects of Polyandry.
-
the evolution of Polyandry intrinsic sire effects contribute to embryo viability
Journal of Evolutionary Biology, 2005Co-Authors: Francisco Garciagonzalez, Leigh W SimmonsAbstract:Females typically mate with more than one male despite the costs incurred, thus questioning Bateman’s principle. A series of genetic benefits have been proposed to account for the evolution of Polyandry, including the acquisition of viability genes for offspring. The ‘intrinsic male quality’ hypothesis suggests that Polyandry increases the probability that females produce offspring sired by males that bestow high viability on their offspring. Heritable variation in viability is the basic requirement for the occurrence of this genetic benefit. By using a half-sib breeding design with a species of cricket in which Polyandry is known to increase hatching success, we present clear experimental evidence that intrinsic male quality contributes to embryo viability. Despite recent support for the evolution of Polyandry based on compatibility of genotypes between males and females, we show that hatching success is not determined by an interaction between paternal and maternal genotypes but rather that sons inherit paternal genes that influence the viability of eggs laid by their mates. Moreover, our data implicate a potential role for indirect genetic effects of male accessory gland products on embryo viability. Additive genetic contributions to embryo viability may be an important factor underlying the frequently observed benefits of polyandrous behaviour.
-
the evolution of Polyandry patterns of genotypic variation in female mating frequency male fertilization success and a test of the sexy sperm hypothesis
Journal of Evolutionary Biology, 2003Co-Authors: Leigh W SimmonsAbstract:The sexy-sperm hypothesis predicts that females obtain indirect benefits for their offspring via polyandy, in the form of increased fertilization success for their sons. I use a quantitative genetic approach to test the sexy-sperm hypothesis using the field cricket Teleogryllus oceanicus. Previous studies of this species have shown considerable phenotypic variation in fertilization success when two or more males compete. There were high broad-sense heritabilities for both paternity and Polyandry. Patterns of genotypic variance were consistent with X-linked inheritance and/or maternal effects on these traits. The genetic architecture therefore precludes the evolution of Polyandry via a sexy-sperm process. Thus the positive genetic correlation between paternity in sons and Polyandry in daughters predicted by the sexy-sperm hypothesis was absent. There was significant heritable variation in the investment by females in ovaries and by males in the accessory gland. Surprisingly there was a very strong genetic correlation between these two traits. The significance of this genetic correlation for the coevolution of male seminal products and Polyandry is discussed.
Nina Wedell - One of the best experts on this subject based on the ideXlab platform.
-
Coevolutionary dynamics of Polyandry and selfish genetic elements
2020Co-Authors: Luke Holman, Tom A. R. Price, Nina Wedell, Hanna KokkoAbstract:Segregation distorters located on sex chromosomes are predicted to sweep to fixation and cause extinction via a shortage of one sex, but in nature they are often found at low, stable frequencies. One potential resolution to this long-standing puzzle involves female multiple mating (Polyandry). Because many meiotic drivers severely reduce the sperm competitive ability of their male carriers, females are predicted to evolve more frequent Polyandry and thereby promote sperm competition when a meiotic driver invades. Consequently, the driving chromosome’s relative fitness should decline, halting or reversing its spread. We used formal modeling to show that this initially appealing hypothesis cannot resolve the puzzle alone: other selective pressures (e.g. low fitness of drive homozygotes) are required to establish a stable meiotic drive polymorphism. However, Polyandry and meiotic drive can strongly affect one another’s frequency, and polyandrous populations may be resistant to the invasion of rare drive mutants.
-
Flexible Polyandry in female flies is an adaptive response to infertile males
Behavioral Ecology, 2019Co-Authors: Andreas Sutter, Laura M. Travers, Tom A. R. Price, Kynan L. Delaney, Stefan J. Store, Nina WedellAbstract:Infertility is common in nature despite its obvious cost to individual fitness. Rising global temperatures are predicted to decrease fertility, and male sterility is frequently used in attempts to regulate pest or disease vector populations. When males are infertile, females may mate with multiple males to ensure fertilization, and changes in female mating behavior in turn could intensify selection on male fertility. Fertility assurance is a potentially wide-spread explanation for Polyandry, but whether and how it actually contributes to the evolution of Polyandry is not clear. Moreover, whether a drop in male fertility would lead to a genetic increase in Polyandry depends on whether females respond genetically or through behavioral plasticity to male infertility. Here, we experimentally manipulate male fertility through heat-exposure in Drosophila pseudoobscura, and test female discrimination against infertile males before and after mating. Using isogenic lines, we compare the roles of behaviorally plastic versus genetically fixed Polyandry. We find that heat-exposed males are less active and attractive, and that females are more likely to remate after mating with these males. Remating rate increases with reduced reproductive output, indicating that females use current sperm storage threshold to make dynamic remating decisions. After remating with fertile males, females restore normal fecundity levels. Our results suggest that male infertility could explain the evolution of adaptively flexible Polyandry, but is less likely to cause an increase in genetic Polyandry.
-
No selection for change in Polyandry under experimental evolution
Journal of Evolutionary Biology, 2019Co-Authors: Andreas Sutter, Laura M. Travers, Melanie Weedon, Tom A. R. Price, Nina WedellAbstract:: What drives mating system variation is a major question in evolutionary biology. Female multiple mating (Polyandry) has diverse evolutionary consequences, and there are many potential benefits and costs of Polyandry. However, our understanding of its evolution is biased towards studies enforcing monandry in polyandrous species. What drives and maintains variation in Polyandry between individuals, genotypes, populations and species remains poorly understood. Genetic variation in Polyandry may be actively maintained by selection, or arise by chance if Polyandry is selectively neutral. In Drosophila pseudoobscura, there is genetic variation in Polyandry between and within populations. We used isofemale lines to found replicate populations with high or low initial levels of Polyandry and tracked Polyandry under experimental evolution over seven generations. Polyandry remained relatively stable, reflecting the starting frequencies of the experimental populations. There were no clear fitness differences between high versus low Polyandry genotypes, and there was no signature of balancing selection. We confirmed these patterns in direct comparisons between evolved and ancestral females and found no consequences of Polyandry for female fecundity. The absence of differential selection even when initiating populations with major differences in Polyandry casts some doubt on the importance of Polyandry for female fitness.
-
coevolutionary dynamics of Polyandry and sex linked meiotic drive
Evolution, 2015Co-Authors: Luke Holman, Tom A. R. Price, Nina Wedell, Hanna KokkoAbstract:: Segregation distorters located on sex chromosomes are predicted to sweep to fixation and cause extinction via a shortage of one sex, but in nature they are often found at low, stable frequencies. One potential resolution to this longstanding puzzle involves female multiple mating (Polyandry). Because many meiotic drivers severely reduce the sperm competitive ability of their male carriers, females are predicted to evolve more frequent Polyandry and thereby promote sperm competition when a meiotic driver invades. Consequently, the driving chromosome's relative fitness should decline, halting or reversing its spread. We used formal modeling to show that this initially appealing hypothesis cannot resolve the puzzle alone: other selective pressures (e.g., low fitness of drive homozygotes) are required to establish a stable meiotic drive polymorphism. However, Polyandry and meiotic drive can strongly affect one another's frequency, and polyandrous populations may be resistant to the invasion of rare drive mutants.
-
Polyandry in nature a global analysis
Trends in Ecology and Evolution, 2014Co-Authors: Michelle L Taylor, Tar Price, Nina WedellAbstract:A popular notion in sexual selection is that females are polyandrous and their offspring are commonly sired by more than a single male. We now have large-scale evidence from natural populations to be able to verify this assumption. Although we concur that Polyandry is a generally common and ubiquitous phenomenon, we emphasise that it remains variable. In particular, the persistence of single paternity, both within and between populations, requires more careful consideration. We also explore an intriguing relation of Polyandry with latitude. Several recent large-scale analyses of the relations between key population fitness variables, such as heterozygosity, effective population size (Ne), and inbreeding coefficients, make it possible to examine the global effects of Polyandry on population fitness for the first time.
Jane M Reid - One of the best experts on this subject based on the ideXlab platform.
-
the consequences of Polyandry for sibship structures distributions of relationships and relatedness and potential for inbreeding in a wild population
The American Naturalist, 2018Co-Authors: Ryan R Germain, Peter Arcese, Jane M ReidAbstract:AbstractThe evolutionary benefits of simultaneous Polyandry (female multiple mating within a single reproductive event) remain elusive. One potential benefit could arise if Polyandry alters sibship structures and consequent relationships and relatedness among females’ descendants, thereby intrinsically reducing future inbreeding risk (the indirect inbreeding avoidance hypothesis). However such effects have not been quantified in naturally complex mating systems that also encompass iteroparity, overlapping generations, sequential Polyandry, and polygyny. We used long-term social and genetic pedigree data from song sparrows (Melospiza melodia) to quantify cross-generational consequences of simultaneous Polyandry for offspring sibship structures and distributions of relationships and relatedness among possible mates. Simultaneous Polyandry decreased full sibships and increased half-sibships, on average, but such effects varied among females and were smaller than would occur in the absence of sequential polya...
-
the consequences of Polyandry for sibship structures distributions of relationships and relatedness and potential for inbreeding in a wild population
bioRxiv, 2017Co-Authors: Ryan R Germain, Peter Arcese, Jane M ReidAbstract:The evolutionary benefits of simultaneous Polyandry, defined as female multiple mating within a single reproductive event, remain elusive. One potential benefit could arise if Polyandry alters sibship structures and consequent relationships and relatedness among females9 descendants, and thereby intrinsically reduces future inbreeding risk (the ‘indirect inbreeding avoidance hypothesis’). However such effects have not been quantified in naturally complex reproductive systems that also encompass iteroparity, overlapping generations, sequential Polyandry, and polygyny. We used long-term social and genetic pedigree data from song sparrows ( Melospiza melodia ) to quantify cross-generational consequences of simultaneous Polyandry for offspring sibship structures and distributions of relationships and relatedness among possible mates. Simultaneous Polyandry decreased full-sibships and increased half-sibships on average, but such effects varied among females and were smaller than would occur in the absence of sequential Polyandry or polygyny. Further, while simultaneous Polyandry decreased the overall frequencies of possible matings among close relatives, it increased the frequencies of possible matings among distant relatives. These results imply that the intrinsic consequences of simultaneous Polyandry for inbreeding risk could cause weak indirect selection on Polyandry, but the magnitude and direction of such effects will depend on complex interactions with other mating system components and the form of inbreeding depression.
-
Evolution Of Pre-Copulatory And Post-Copulatory Strategies Of Inbreeding Avoidance And Associated Polyandry
bioRxiv, 2017Co-Authors: A. Bradley Duthie, Ryan R Germain, Greta Bocedi, Jane M ReidAbstract:Inbreeding depression is widely hypothesised to drive adaptive evolution of pre-copulatory and post-copulatory mechanisms of inbreeding avoidance, which in turn are hypothesised to affect evolution of Polyandry (i.e., female multiple mating). However, surprisingly little theory or modelling critically examines selection for pre-copulatory or post-copulatory inbreeding avoidance, or both strategies, given evolutionary constraints and direct costs, or examines how evolution of inbreeding avoidance strategies might feed back to affect evolution of Polyandry. Selection for post-copulatory inbreeding avoidance, but not for pre-copulatory inbreeding avoidance, requires Polyandry, while interactions between pre-copulatory and post-copulatory inbreeding avoidance might cause functional redundancy (i.e., ‘degeneracy’) potentially generating complex evolutionary dynamics among inbreeding strategies and Polyandry. We use individual-based modelling to quantify evolution of interacting pre-copulatory and post-copulatory inbreeding avoidance and associated Polyandry given strong inbreeding depression and different evolutionary constraints and direct costs. We find that evolution of post-copulatory inbreeding avoidance increases selection for initially rare Polyandry, and that selection for a costly inbreeding avoidance strategy was weak or negligible given a cost free alternative strategy. Further, fixed pre-copulatory inbreeding avoidance often completely precluded evolution of Polyandry and hence post-copulatory inbreeding avoidance, but fixed post-copulatory inbreeding avoidance did not preclude evolution of pre-copulatory inbreeding avoidance. Evolution of inbreeding avoidance phenotypes and associated Polyandry are therefore affected by evolutionary feedbacks and degeneracy. All else being equal, evolution of pre-copulatory inbreeding avoidance and resulting low Polyandry is more likely when post-copulatory inbreeding avoidance is precluded or costly, and evolution of post-copulatory inbreeding avoidance greatly facilitates evolution of costly Polyandry.
Francisco Garciagonzalez - One of the best experts on this subject based on the ideXlab platform.
-
additive genetic variance in Polyandry enables its evolution but Polyandry is unlikely to evolve through sexy or good sperm processes
Journal of Evolutionary Biology, 2016Co-Authors: Laura M. Travers, Leigh W Simmons, Francisco GarciagonzalezAbstract:: Polyandry is widespread despite its costs. The sexually selected sperm hypotheses ('sexy' and 'good' sperm) posit that sperm competition plays a role in the evolution of Polyandry. Two poorly studied assumptions of these hypotheses are the presence of additive genetic variance in Polyandry and sperm competitiveness. Using a quantitative genetic breeding design in a natural population of Drosophila melanogaster, we first established the potential for Polyandry to respond to selection. We then investigated whether Polyandry can evolve through sexually selected sperm processes. We measured lifetime Polyandry and offensive sperm competitiveness (P2 ) while controlling for sampling variance due to male × male × female interactions. We also measured additive genetic variance in egg-to-adult viability and controlled for its effect on P2 estimates. Female lifetime Polyandry showed significant and substantial additive genetic variance and evolvability. In contrast, we found little genetic variance or evolvability in P2 or egg-to-adult viability. Additive genetic variance in Polyandry highlights its potential to respond to selection. However, the low levels of genetic variance in sperm competitiveness suggest that the evolution of Polyandry may not be driven by sexy sperm or good sperm processes.
-
bet hedging as a mechanism for the evolution of Polyandry revisited
Evolution, 2016Co-Authors: Yukio Yasui, Francisco GarciagonzalezAbstract:: Females that mate with multiple males (Polyandry) may reduce the risk that their eggs are fertilized by a single unsuitable male. About 25 years ago it was hypothesized that bet-hedging could function as a mechanism favoring the evolution of Polyandry, but this idea is controversial because theory indicates that bet-hedging via Polyandry can compensate the costs of mating only in small populations. Nevertheless, populations are often spatially structured, and even in the absence of spatial structure, mate-choice opportunity can be limited to a few potential partners. We examined the effectiveness of bet-hedging in such situations with simulations carried out under two scenarios: (1) intrinsic male quality, with offspring survival determined by male phenotype (male's ability to generate viable offspring), and (2) genetic incompatibility (offspring fitness determined nonadditively by parental genotypes). We find higher fixation probabilities for a polyandrous strategy compared to a monandrous strategy if complete reproductive failure due to male effects or parental incompatibility is pervasive in the population. Our results also indicate that bet-hedging Polyandry can delay the extinction of small demes. Our results underscore the potential for bet-hedging to provide benefits to polyandrous females and have valuable implications for conservation biology.
-
the evolution of Polyandry intrinsic sire effects contribute to embryo viability
Journal of Evolutionary Biology, 2005Co-Authors: Francisco Garciagonzalez, Leigh W SimmonsAbstract:Females typically mate with more than one male despite the costs incurred, thus questioning Bateman’s principle. A series of genetic benefits have been proposed to account for the evolution of Polyandry, including the acquisition of viability genes for offspring. The ‘intrinsic male quality’ hypothesis suggests that Polyandry increases the probability that females produce offspring sired by males that bestow high viability on their offspring. Heritable variation in viability is the basic requirement for the occurrence of this genetic benefit. By using a half-sib breeding design with a species of cricket in which Polyandry is known to increase hatching success, we present clear experimental evidence that intrinsic male quality contributes to embryo viability. Despite recent support for the evolution of Polyandry based on compatibility of genotypes between males and females, we show that hatching success is not determined by an interaction between paternal and maternal genotypes but rather that sons inherit paternal genes that influence the viability of eggs laid by their mates. Moreover, our data implicate a potential role for indirect genetic effects of male accessory gland products on embryo viability. Additive genetic contributions to embryo viability may be an important factor underlying the frequently observed benefits of polyandrous behaviour.
Tom A. R. Price - One of the best experts on this subject based on the ideXlab platform.
-
Coevolutionary dynamics of Polyandry and selfish genetic elements
2020Co-Authors: Luke Holman, Tom A. R. Price, Nina Wedell, Hanna KokkoAbstract:Segregation distorters located on sex chromosomes are predicted to sweep to fixation and cause extinction via a shortage of one sex, but in nature they are often found at low, stable frequencies. One potential resolution to this long-standing puzzle involves female multiple mating (Polyandry). Because many meiotic drivers severely reduce the sperm competitive ability of their male carriers, females are predicted to evolve more frequent Polyandry and thereby promote sperm competition when a meiotic driver invades. Consequently, the driving chromosome’s relative fitness should decline, halting or reversing its spread. We used formal modeling to show that this initially appealing hypothesis cannot resolve the puzzle alone: other selective pressures (e.g. low fitness of drive homozygotes) are required to establish a stable meiotic drive polymorphism. However, Polyandry and meiotic drive can strongly affect one another’s frequency, and polyandrous populations may be resistant to the invasion of rare drive mutants.
-
Flexible Polyandry in female flies is an adaptive response to infertile males
Behavioral Ecology, 2019Co-Authors: Andreas Sutter, Laura M. Travers, Tom A. R. Price, Kynan L. Delaney, Stefan J. Store, Nina WedellAbstract:Infertility is common in nature despite its obvious cost to individual fitness. Rising global temperatures are predicted to decrease fertility, and male sterility is frequently used in attempts to regulate pest or disease vector populations. When males are infertile, females may mate with multiple males to ensure fertilization, and changes in female mating behavior in turn could intensify selection on male fertility. Fertility assurance is a potentially wide-spread explanation for Polyandry, but whether and how it actually contributes to the evolution of Polyandry is not clear. Moreover, whether a drop in male fertility would lead to a genetic increase in Polyandry depends on whether females respond genetically or through behavioral plasticity to male infertility. Here, we experimentally manipulate male fertility through heat-exposure in Drosophila pseudoobscura, and test female discrimination against infertile males before and after mating. Using isogenic lines, we compare the roles of behaviorally plastic versus genetically fixed Polyandry. We find that heat-exposed males are less active and attractive, and that females are more likely to remate after mating with these males. Remating rate increases with reduced reproductive output, indicating that females use current sperm storage threshold to make dynamic remating decisions. After remating with fertile males, females restore normal fecundity levels. Our results suggest that male infertility could explain the evolution of adaptively flexible Polyandry, but is less likely to cause an increase in genetic Polyandry.
-
No selection for change in Polyandry under experimental evolution
Journal of Evolutionary Biology, 2019Co-Authors: Andreas Sutter, Laura M. Travers, Melanie Weedon, Tom A. R. Price, Nina WedellAbstract:: What drives mating system variation is a major question in evolutionary biology. Female multiple mating (Polyandry) has diverse evolutionary consequences, and there are many potential benefits and costs of Polyandry. However, our understanding of its evolution is biased towards studies enforcing monandry in polyandrous species. What drives and maintains variation in Polyandry between individuals, genotypes, populations and species remains poorly understood. Genetic variation in Polyandry may be actively maintained by selection, or arise by chance if Polyandry is selectively neutral. In Drosophila pseudoobscura, there is genetic variation in Polyandry between and within populations. We used isofemale lines to found replicate populations with high or low initial levels of Polyandry and tracked Polyandry under experimental evolution over seven generations. Polyandry remained relatively stable, reflecting the starting frequencies of the experimental populations. There were no clear fitness differences between high versus low Polyandry genotypes, and there was no signature of balancing selection. We confirmed these patterns in direct comparisons between evolved and ancestral females and found no consequences of Polyandry for female fecundity. The absence of differential selection even when initiating populations with major differences in Polyandry casts some doubt on the importance of Polyandry for female fitness.
-
coevolutionary dynamics of Polyandry and sex linked meiotic drive
Evolution, 2015Co-Authors: Luke Holman, Tom A. R. Price, Nina Wedell, Hanna KokkoAbstract:: Segregation distorters located on sex chromosomes are predicted to sweep to fixation and cause extinction via a shortage of one sex, but in nature they are often found at low, stable frequencies. One potential resolution to this longstanding puzzle involves female multiple mating (Polyandry). Because many meiotic drivers severely reduce the sperm competitive ability of their male carriers, females are predicted to evolve more frequent Polyandry and thereby promote sperm competition when a meiotic driver invades. Consequently, the driving chromosome's relative fitness should decline, halting or reversing its spread. We used formal modeling to show that this initially appealing hypothesis cannot resolve the puzzle alone: other selective pressures (e.g., low fitness of drive homozygotes) are required to establish a stable meiotic drive polymorphism. However, Polyandry and meiotic drive can strongly affect one another's frequency, and polyandrous populations may be resistant to the invasion of rare drive mutants.
-
does Polyandry control population sex ratio via regulation of a selfish gene
Proceedings of The Royal Society B: Biological Sciences, 2014Co-Authors: Tom A. R. Price, Amanda Bretman, Ana C Gradilla, Julia Reger, Michelle L Taylor, Paulina Giraldoperez, Amy Campbell, Gregory D D HurstAbstract:The extent of female multiple mating (Polyandry) can strongly impact on the intensity of sexual selection, sexual conflict, and the evolution of cooperation and sociality. More subtly, Polyandry may protect populations against intragenomic conflicts that result from the invasion of deleterious selfish genetic elements (SGEs). SGEs commonly impair sperm production, and so are likely to be unsuccessful in sperm competition, potentially reducing their transmission in polyandrous populations. Here, we test this prediction in nature. We demonstrate a heritable latitudinal cline in the degree of Polyandry in the fruitfly Drosophila pseudoobscura across the USA, with northern population females remating more frequently in both the field and the laboratory. High remating was associated with low frequency of a sex-ratio-distorting meiotic driver in natural populations. In the laboratory, Polyandry directly controls the frequency of the driver by undermining its transmission. Hence we suggest that the cline in Polyandry represents an important contributor to the cline in sex ratio in nature. Furthermore, as the meiotic driver causes sex ratio bias, variation in Polyandry may ultimately determine population sex ratio across the USA, a dramatic impact of female mating decisions. As SGEs are ubiquitous it is likely that the reduction of intragenomic conflict by Polyandry is widespread.