Sexual selection affects the evolution of contact pheromones in Drosophila melanogaster populations isolated by differential sexual conflict

Abstract Background: The ability of sexual conflict to facilitate reproductive isolation is widely anticipated. However, very few experimental evolutionary studies have convincingly demonstrated the evolution of reproductive isolation due to sexual conflict. Recently a study on the replicates of Drosophila melanogaster populations under differential sexual conflict found that divergent mate preference evolved among replicates under high sexual conflict regime. The precopulatory isolating mechanism underlying such divergent mate preference could be sexual signals such as cuticular lipids since they evolve rapidly and are involved in D. melanogaster mate recognition. Using Drosophila melanogaster replicates used in the previous study, we investigate whether cuticular lipid divergence bears signatures of sexually antagonistic coevolution that led to reproductive isolation among replicates of high sexual conflict regime. Results: We found that their cuticular lipid profiles are sexually dimorphic. Although replicates with male biased sex ratio evolved isolation in reproductive traits due to high sexual conflict, the patterns of cuticular lipid divergence in high and low sexual conflict regimes suggest that sexual selection is the dominant selection pressure rather than sexual conflict affecting the cuticular lipid profile. We also find cuticular lipid divergence patterns to be suggestive of the Buridan’s Ass regime which is one of the six possible mechanism to resolve sexual conflict. Conclusions: Although reproductive isolation due to sexual conflict is anticipated, evolution of a sexually selected trait under sexual conflict may not lead to population differentiation in expected lines. This is because speciation due to sexually antagonistic coevolution is only one of the several outcomes of sexual conflict. This study indicates that population differentiation as a result of cuticular lipid divergence cannot be credited to sexual conflict despite high sexual conflict regime evolving divergent cuticular lipid profiles.

Reproductive Isolation through Experimental Manipulation of Sexually Antagonistic Coevolution in Drosophila melanogaster

10.1101/079657 ◽

2016 ◽

Author(s):

Syed Zeeshan Ali ◽

Martik Chatterjee ◽

Manas Arun Samant ◽

Nagaraj Guru Prasad

Keyword(s):

Drosophila Melanogaster ◽

Reproductive Isolation ◽

Sexual Conflict ◽

Evolutionary Model ◽

Experimental Manipulation ◽

Allopatric Populations ◽

Before And After ◽

Postmating Prezygotic Isolation ◽

AbstractPromiscuity can drive the evolution of sexual conflict before and after mating occurs. Post-mating, the male ejaculate can selfishly manipulate female physiology leading to a chemical arms race between the sexes. Theory suggests that drift and sexually antagonistic coevolution can cause allopatric populations to evolve different chemical interactions between the sexes, thereby leading to postmating reproductive barriers and speciation. There is, however, little empirical evidence supporting this form of speciation. We tested this theory by creating an experimental evolutionary model of Drosophila melanogaster populations undergoing different levels of interlocus sexual conflict. We found that allopatric populations under elevated sexual conflict show assortative mating indicating premating reproductive isolation. Further, these allopatric populations also show reduced copulation duration and sperm defense ability when mating happens between individuals between individuals across populations compared to that within the same population, indicating postmating prezygotic isolation. Sexual conflict can cause reproductive isolation in allopatric populations through the coevolution of chemical (postmating prezygotic) as well as behavioural (premating) interaction between the sexes. Thus, to our knowledge, we provide the first comprehensive evidence of postmating (as well as premating) reproductive isolation due to sexual conflict.

Does reproductive isolation evolve faster in larger populations via sexually antagonistic coevolution?

Biology Letters ◽

10.1098/rsbl.2009.0072 ◽

2009 ◽

Vol 5 (5) ◽

pp. 693-696 ◽

Cited By ~ 24

Author(s):

L. Gay ◽

P.E. Eady ◽

R. Vasudev ◽

D.J. Hosken ◽

T. Tregenza

Keyword(s):

Genetic Variation ◽

Sexual Selection ◽

Genetic Variability ◽

Reproductive Isolation ◽

Sexual Conflict ◽

Callosobruchus Maculatus ◽

Reproductive Investment ◽

Large Populations ◽

Sexual conflict over reproductive investment can lead to sexually antagonistic coevolution and reproductive isolation. It has been suggested that, unlike most models of allopatric speciation, the evolution of reproductive isolation through sexually antagonistic coevolution will occur faster in large populations as these harbour greater levels of standing genetic variation, receive larger numbers of mutations and experience more intense sexual selection. We tested this in bruchid beetle populations ( Callosobruchus maculatus ) by manipulating population size and standing genetic variability in replicated lines derived from founders that had been released from sexual conflict for 90 generations. We found that after 19 generations of reintroduced sexual conflict, none of our treatments had evolved significant overall reproductive isolation among replicate lines. However, as predicted, measures of reproductive isolation tended to be greater among larger populations. We discuss our methodology, arguing that reproductive isolation is best examined by performing a matrix of allopatric and sympatric crosses whereas measurement of divergence requires crosses with a tester line.

Quantifying the gender load: can population crosses reveal interlocus sexual conflict?

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2005.1786 ◽

2006 ◽

Vol 361 (1466) ◽

pp. 363-374 ◽

Cited By ~ 32

Author(s):

Tristan A.F Long ◽

Robert Montgomerie ◽

Adam K Chippindale

Keyword(s):

Sperm Competition ◽

Sexual Conflict ◽

Population Differentiation ◽

Population Divergence ◽

Mating Frequency ◽

Female Reproduction ◽

Female Fitness ◽

The Cost ◽

Six sister populations of Drosophila melanogaster kept under identical environmental conditions for greater than 600 generations were reciprocally crossed to investigate the incidence of population divergence in allopatry. Population crosses directly influenced fitness, mating frequency, and sperm competition patterns. Changes in both female remating rate and the outcome of male sperm competition (P 1 , P 2 ) in response to foreign males were consistent with intersexual coevolution. Moreover, seven of the 30 crosses between foreign mates resulted in significant reductions in female fitness, whereas two resulted in significant increases, compared to local matings. This tendency for foreign males to reduce female fitness may be interpreted as evidence for either sexually antagonistic coevolution or the disruption of mutualistic interactions. However, instances in which female fitness improved via cohabitation with foreign males may better reveal sexual conflict, signalling release from the cost of interacting with locally adapted males. By this metric, female reproduction in D. melanogaster is strongly constrained by local adaptation by males, a situation that would promote antagonistic coevolution between the sexes. We conclude that sexual selection can promote population differentiation in allopatry and that sexual conflict is likely to have played a role in population differentiation in this study system.

Assessing sexual conflict in the Drosophila melanogaster laboratory model system

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2005.1787 ◽

2006 ◽

Vol 361 (1466) ◽

pp. 287-299 ◽

Cited By ~ 89

Author(s):

William R Rice ◽

Andrew D Stewart ◽

Edward H Morrow ◽

Jodell E Linder ◽

Nicole Orteiza ◽

...

Keyword(s):

Drosophila Melanogaster ◽

Sexual Selection ◽

Sexual Conflict ◽

Graphical Model ◽

Direct Costs ◽

Model System ◽

Laboratory Model ◽

Laboratory Populations ◽

Spatial Refuge ◽

We describe a graphical model of interlocus coevolution used to distinguish between the interlocus sexual conflict that leads to sexually antagonistic coevolution, and the intrinsic conflict over mating rate that is an integral part of traditional models of sexual selection. We next distinguish the ‘laboratory island’ approach from the study of both inbred lines and laboratory populations that are newly derived from nature, discuss why we consider it to be one of the most fitting forms of laboratory analysis to study interlocus sexual conflict, and then describe four experiments using this approach with Drosophila melanogaster . The first experiment evaluates the efficacy of the laboratory model system to study interlocus sexual conflict by comparing remating rates of females when they are, or are not, provided with a spatial refuge from persistent male courtship. The second experiment tests for a lag-load in males that is due to adaptations that have accumulated in females, which diminish male-induced harm while simultaneously interfering with a male's ability to compete in the context of sexual selection. The third and fourth experiments test for a lag-load in females owing to direct costs from their interactions with males, and for the capacity for indirect benefits to compensate for these direct costs.

Cuticular hydrocarbon divergence in Drosophila melanogaster populations evolving under differential operational sex ratios

10.1101/351718 ◽

2018 ◽

Author(s):

Rochishnu Dutta ◽

Tejinder Singh Chechi ◽

Ankit Yadav ◽

Nagaraj Guru Prasad

Keyword(s):

Drosophila Melanogaster ◽

Reproductive Isolation ◽

Cuticular Hydrocarbons ◽

Sexual Conflict ◽

Cuticular Hydrocarbon ◽

Mate Recognition ◽

Mate Preference ◽

Sexually Dimorphic ◽

Cuticular Hydrocarbon Profile ◽

Buridan’S Ass

AbstractThe ability of interlocus sexual conflict to facilitate reproductive isolation is widely anticipated. However, very few experimental evolutionary studies have convincingly demonstrated the evolution of reproductive isolation due to sexual conflict. Recently a study on replicate populations of Drosophila melanogaster under differential sexual conflict found that divergent mate preference evolved among replicate populations under high sexual conflict regime. The precopulatory isolating mechanism underlying such divergent mate preference could be sexual signals such as cuticular hydrocarbons since they evolve rapidly and are involved in D. melanogaster mate recognition. Using D. melanogaster replicates used in the previous study, we investigate whether cuticular hydrocarbon divergence bears signatures of sexually antagonistic coevolution that led to reproductive isolation among replicates of high sexual conflict regime. We found that D. melanogaster cuticular hydrocarbon profiles are sexually dimorphic. Although replicate populations under high sexual conflict displayed assortative mating, we found no significant differences in the cuticular hydrocarbon profile between the high and low sexual conflict regimes. Instead we find cuticular hydrocarbon divergence patterns to be suggestive of the Buridan’s Ass regime which is one of the six possible mechanisms to resolve sexual conflict. Sexual selection that co-vary between populations under high and low sexual conflict regimes may also have contributed to the evolution of cuticular hydrocarbons. This study indicates that population differentiation as a result of cuticular hydrocarbon divergence cannot be credited to sexual conflict despite high sexual conflict regime evolving divergent cuticular hydrocarbon profiles.