Limits...
Reproductive behaviour evolves rapidly when intralocus sexual conflict is removed.

Bedhomme S, Prasad NG, Jiang PP, Chippindale AK - PLoS ONE (2008)

Bottom Line: On the other hand, our data suggest that females expressing the ML genomes had reduced attractiveness, stimulating a lower rate of courtship from males.Moreover, females expressing ML genomes tend to display reduced yeast-feeding behaviour, which is probably linked to the reduction of their fecundity.These results suggest that reproductive behaviour is shaped by opposing selection on males and females, and that loci influencing attractiveness and foraging were polymorphic for alleles with sexually antagonistic expression patterns prior to ML selection.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Queen's University, Kingston, Ontario, Canada. sbedh_01@uni-muenster.de

ABSTRACT

Background: Intralocus sexual conflict can inhibit the evolution of each sex towards its own fitness optimum. In a previous study, we confirmed this prediction through the experimental removal of female selection pressures in Drosophila melanogaster, achieved by limiting the expression of all major chromosomes to males. Compared to the control populations (C(1-4)) where the genomes are exposed to selection in both sexes, the populations with male-limited genomes (ML(1-4)) showed rapid increases in male fitness, whereas the fitness of females expressing ML-evolved chromosomes decreased.

Methodology/principal findings: Here we examine the behavioural phenotype underlying this sexual antagonism. We show that males expressing the ML genomes have a reduced courtship level but acquire the same number of matings. On the other hand, our data suggest that females expressing the ML genomes had reduced attractiveness, stimulating a lower rate of courtship from males. Moreover, females expressing ML genomes tend to display reduced yeast-feeding behaviour, which is probably linked to the reduction of their fecundity.

Conclusion/significance: These results suggest that reproductive behaviour is shaped by opposing selection on males and females, and that loci influencing attractiveness and foraging were polymorphic for alleles with sexually antagonistic expression patterns prior to ML selection. Hence, intralocus sexual conflict appears to play a role in the evolution of a wide range of fitness-related traits and may be a powerful mechanism for the maintenance of genetic variation in fitness.

Show MeSH
Total number of courtship events and their orientation observed in 7 hourly checks of each vial (± s.e.) when male-limited (ML) evolved chromosomes (shaded bars) and Control (open bars) were expressed in males (A) and in females (B).All measurements are from vials housing both sexes. Males expressing ML chromosomes courted at a significantly lower rate than control males did. Females expressing ML chromosomes were courted at a significantly lower rate than controls, and were also associated with lower rates of homosexual courtship.
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pone-0002187-g001: Total number of courtship events and their orientation observed in 7 hourly checks of each vial (± s.e.) when male-limited (ML) evolved chromosomes (shaded bars) and Control (open bars) were expressed in males (A) and in females (B).All measurements are from vials housing both sexes. Males expressing ML chromosomes courted at a significantly lower rate than control males did. Females expressing ML chromosomes were courted at a significantly lower rate than controls, and were also associated with lower rates of homosexual courtship.

Mentions: In order to determine if intralocus sexual conflict affected the evolution of courtship intensity and mating frequency, we recorded courtship and matings of males expressing ML and C genomes. Over the whole observation period, males expressing ML-evolved genomes showed lower levels of courtship activity compared to control males (t3 = 8.21, p = 0.004, figure 1A). This reflected both a decrease in courtship directed to females (t3 = 6.18, p = 0.009, figure 1A) and to other males (t3 = 3.45, p = 0.041, figure 1A, table 1). Nonetheless ML males acquired matings at the same rate as did C males (t3 = 1.22, p = 0.309, figure 2, table 1). As noted above, however, if matings with less-discriminating virgin females accounted for the majority of our observations, then this result could be interpreted as a generic reduction in male mating effort; an unexpected result given increased competitive fitness in the ML lines. Because of the observation protocol, the number of matings actually occurring could be as much as 3 times the number observed; we checked the vials hourly but the mounted period in D. melanogaster lasts for approximately 15 to 20 min (16.5 ± S.D. 3.3 minutes in the LHM population; J. Sy, pers. comm.).


Reproductive behaviour evolves rapidly when intralocus sexual conflict is removed.

Bedhomme S, Prasad NG, Jiang PP, Chippindale AK - PLoS ONE (2008)

Total number of courtship events and their orientation observed in 7 hourly checks of each vial (± s.e.) when male-limited (ML) evolved chromosomes (shaded bars) and Control (open bars) were expressed in males (A) and in females (B).All measurements are from vials housing both sexes. Males expressing ML chromosomes courted at a significantly lower rate than control males did. Females expressing ML chromosomes were courted at a significantly lower rate than controls, and were also associated with lower rates of homosexual courtship.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2367451&req=5

pone-0002187-g001: Total number of courtship events and their orientation observed in 7 hourly checks of each vial (± s.e.) when male-limited (ML) evolved chromosomes (shaded bars) and Control (open bars) were expressed in males (A) and in females (B).All measurements are from vials housing both sexes. Males expressing ML chromosomes courted at a significantly lower rate than control males did. Females expressing ML chromosomes were courted at a significantly lower rate than controls, and were also associated with lower rates of homosexual courtship.
Mentions: In order to determine if intralocus sexual conflict affected the evolution of courtship intensity and mating frequency, we recorded courtship and matings of males expressing ML and C genomes. Over the whole observation period, males expressing ML-evolved genomes showed lower levels of courtship activity compared to control males (t3 = 8.21, p = 0.004, figure 1A). This reflected both a decrease in courtship directed to females (t3 = 6.18, p = 0.009, figure 1A) and to other males (t3 = 3.45, p = 0.041, figure 1A, table 1). Nonetheless ML males acquired matings at the same rate as did C males (t3 = 1.22, p = 0.309, figure 2, table 1). As noted above, however, if matings with less-discriminating virgin females accounted for the majority of our observations, then this result could be interpreted as a generic reduction in male mating effort; an unexpected result given increased competitive fitness in the ML lines. Because of the observation protocol, the number of matings actually occurring could be as much as 3 times the number observed; we checked the vials hourly but the mounted period in D. melanogaster lasts for approximately 15 to 20 min (16.5 ± S.D. 3.3 minutes in the LHM population; J. Sy, pers. comm.).

Bottom Line: On the other hand, our data suggest that females expressing the ML genomes had reduced attractiveness, stimulating a lower rate of courtship from males.Moreover, females expressing ML genomes tend to display reduced yeast-feeding behaviour, which is probably linked to the reduction of their fecundity.These results suggest that reproductive behaviour is shaped by opposing selection on males and females, and that loci influencing attractiveness and foraging were polymorphic for alleles with sexually antagonistic expression patterns prior to ML selection.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Queen's University, Kingston, Ontario, Canada. sbedh_01@uni-muenster.de

ABSTRACT

Background: Intralocus sexual conflict can inhibit the evolution of each sex towards its own fitness optimum. In a previous study, we confirmed this prediction through the experimental removal of female selection pressures in Drosophila melanogaster, achieved by limiting the expression of all major chromosomes to males. Compared to the control populations (C(1-4)) where the genomes are exposed to selection in both sexes, the populations with male-limited genomes (ML(1-4)) showed rapid increases in male fitness, whereas the fitness of females expressing ML-evolved chromosomes decreased.

Methodology/principal findings: Here we examine the behavioural phenotype underlying this sexual antagonism. We show that males expressing the ML genomes have a reduced courtship level but acquire the same number of matings. On the other hand, our data suggest that females expressing the ML genomes had reduced attractiveness, stimulating a lower rate of courtship from males. Moreover, females expressing ML genomes tend to display reduced yeast-feeding behaviour, which is probably linked to the reduction of their fecundity.

Conclusion/significance: These results suggest that reproductive behaviour is shaped by opposing selection on males and females, and that loci influencing attractiveness and foraging were polymorphic for alleles with sexually antagonistic expression patterns prior to ML selection. Hence, intralocus sexual conflict appears to play a role in the evolution of a wide range of fitness-related traits and may be a powerful mechanism for the maintenance of genetic variation in fitness.

Show MeSH