scholarly journals THE EFFECT OF INBREEDING ON COMPETITIVE MALE-MATING ABILITY IN DROSOPHILA MELANOGASTER

Genetics ◽  
1984 ◽  
Vol 106 (4) ◽  
pp. 601-612
Author(s):  
Paul M Sharp
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Sexual Selection ◽  
Strong Influence ◽  
Inbred Lines ◽  
Male Mating ◽  
Male Body ◽  
Mating Ability ◽  
Sib Mating ◽  
The Difference

ABSTRACT The effect of full-sib inbreeding on competitive male-mating ability (CI♂) in Drosophila melanogaster was investigated in two experiments. In the first, five inbred lines (with reserves) were assessed up to 18 generations. Linear inbreeding depression, of 5.9% per 10% increase in homozygosity, was observed. In a second experiment, 21 inbred lines were tested after three generations of full-sib mating (without reserves), and the decline with inbreeding was more severe, the male competitive index (CI♂) decreasing by 10.7% per 10% increase in F. The difference between these results is attributed to natural selection acting on variation within the inbred lines in extent of homozygosity, which can arise because of the peculiarly strong influence of linkage in Drosophila. Furthermore, differentiation between the lines may have reflected this variation rather than the various effects of different alleles fixed.—These results imply that the genetic variation in male-mating ability is largely due to dominance (no epistasis was detected) and are consonant with the proposition that intermale sexual selection is a very important component of fitness in D. melanogaster. There was no evidence of a positive correlation between male body size and competitive mating ability.

scholarly journals The inbreeding decline and average dominance of genes affecting male life-history characters in Drosophila melanogaster

1995 ◽  
Vol 65 (1) ◽  
pp. 41-52 ◽  
Author(s):  
Kimberly A. Hughes
Keyword(s):  
Drosophila Melanogaster ◽  
Life History ◽  
Male Fertility ◽  
Laboratory Population ◽  
Male Mating ◽  
Fitness Components ◽  
Components Of Variance ◽  
Mating Ability ◽  
Deleterious Alleles ◽  
Male Life History

SummaryThis paper describes the results of assays of male life-history characters in a large outbred laboratory population of D. melanogaster. Lines of flies homozygous for the entire third chromosome and lines of flies carrying two different third chromosomes were assayed for agespecific male mating ability (MMA), age-specific survivorship, male fertility, and body mass. The results of these assays were used to calculate the inbreeding decline associated with each of these traits, the average dominance of deleterious alleles that affect the traits, the genotypic and environmental components of variance for the homozygous lines, and phenotypic and genotypic correlations among the characters. Significant inbreeding decline was found for all characters except the Gompertz intercept and fertility. Early and late MMA show larger effects of inbreeding than any other trait. The inbreeding load for MMA is about the same magnitude as that for egg-to-adult viability, but is substantially less than that associated with total fitness. The estimated inbreeding decline and average dominance of male life-history characters are comparable to estimates for other Drosophila fitness components.

scholarly journals Competitive mating in Drosophila melanogaster

1982 ◽  
Vol 40 (2) ◽  
pp. 201-205 ◽  
Author(s):  
Paul M. Sharp
Keyword(s):  
Drosophila Melanogaster ◽  
Test Procedure ◽  
Limited Resource ◽  
Receptive Female ◽  
Male Mating ◽  
Large Reduction ◽  
Mating Ability ◽  
Male Ratio ◽  
The Past

SUMMARYSelective differences among male Drosophila melanogaster due to differences in ability to compete for mates may often have been under-estimated in the past because, under the test procedure used, females did not represent a limited resource. In the experiment reported here, no difference was detected between inbred and outbred males ‘competing’ to mate with an equal number of females. When the receptive female: male ratio was halved a large reduction in male mating ability due to inbreeding became apparent.

scholarly journals GENETIC VARIATION AND GENETIC LOAD DUE TO THE MALE REPRODUCTIVE COMPONENT OF FITNESS IN DROSOPHILA

Genetics ◽  
1981 ◽  
Vol 97 (3-4) ◽  
pp. 719-730
Author(s):  
John G Brittnacher
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Female Choice ◽  
Genetic Load ◽  
Competition Experiment ◽  
Male Mating ◽  
Mating Competition ◽  
Mating Propensity ◽  
The Mean ◽  
Male Mating Competition

ABSTRACT The genetic variation and genetic load due to virility, the male reproductive component of fitness, was measured in Drosophila melanogaster and D. pseudoobscura using males homozygous and heterozygous for the second chromosome of each species. Virility was determined in a female-choice, male mating competition experiment where both mating propensity and fertility were taken into account.——The mean virility of the homozygous D. melanogaster males relative to the heterozygous males was 0.50; the relative mean virility of the quasinormal homozygotes was 0.56. The mean virility of the homozygous D. pseudoobscura males relative to the heterozygous males was 0.70; the relative mean virility of the nonsterile homozygotes was 0.72, and of the quasinormal homozygotes, 0.68.——Depending on the species and chromosome sampled, fertile homozygous males had a mean virility 15 to 50% lower than the mean viability of individuals homozygous for a chromosome with quasinormal viability. The genetic load due to virility was also greater than that due to the female reproductive component. This higher level of hidden genetic variation (or genetic load) indicates that the results of PROUT(1971a, b) and BUNDGAARD and CHRISTIANSEN(1972), where the virility component of fitness dominated the dynamics of an artificial polymorphism, may be more general and that virility may dominate the dynamics of natural polymorphisms as well.

scholarly journals Genetic variation in male-induced harm in Drosophila melanogaster

2016 ◽  
Vol 12 (4) ◽  
pp. 20160105 ◽  
Author(s):  
David C. S. Filice ◽  
Tristan A. F. Long
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Prolonged Exposure ◽  
Harmful Effect ◽  
Accessory Gland ◽  
Evolutionary Significance ◽  
Male Body ◽  
Accessory Gland Proteins ◽  
Trade Offs ◽  
Fitness Index

In Drosophila melanogaster , prolonged exposure to males reduces the longevity and fecundity of females. This harm arises from the effects of male courtship behaviours and the toxic side effects of the accessory gland proteins (Acps) in their seminal fluids. Here, we examine the relationship between male exposure and its harmful effect on the lifetime fitness of his mates, and quantify the genetic basis for this variation. We found significant additive genetic variation in the magnitude of harm that males impose on females by exposing females to males from a variety of hemiclonal backgrounds for either a brief or prolonged period of time and measuring their fecundity, a meaningful fitness index. Furthermore, we discovered a strong negative correlation between the magnitude of harm and the short-term effects of male exposure on female fitness. We discuss the evolutionary significance of these results with regards to potential life-history trade-offs in females, and its relationship to male body size.

scholarly journals Autosomal variation for male body size and sperm competition phenotypes is uncorrelated in Drosophila melanogaster

2008 ◽  
Vol 4 (5) ◽  
pp. 500-503 ◽  
Author(s):  
Rui Zhang ◽  
Linda Amah ◽  
Anthony C Fiumera
Keyword(s):  
Drosophila Melanogaster ◽  
Sexual Selection ◽  
Body Size ◽  
Genetic Correlations ◽  
Male Body ◽  
Substitution Lines ◽  
Male Body Size ◽  
Chromosome Substitution Lines ◽  
Significant Line ◽  
Sexually Antagonistic Coevolution

Correlations between male body size and phenotypes impacting post-copulatory sexual selection are commonly observed during the manipulation of male body size by environmental rearing conditions. Here, we control for environmental influences and test for genetic correlations between natural variation in male body size and phenotypes affecting post-copulatory sexual selection in Drosophila melanogaster . Dry weights of virgin males from 90 second-chromosome and 88 third-chromosome substitution lines were measured. Highly significant line effects ( p <0.001) documented a genetic basis to variation in male body size. No significant correlations were identified between male body size and the components of sperm competitive ability. These results suggest that natural autosomal variation for male body size has little impact on post-copulatory sexual selection. If genetic correlations exist between male body size and post-copulatory sexual selection then variation in the sex chromosomes are likely candidates, as might be expected if sexually antagonistic coevolution was responsible.

scholarly journals A QTL analysis of female variation contributing to refractoriness and sperm competition in Drosophila melanogaster

2005 ◽  
Vol 86 (2) ◽  
pp. 107-114 ◽  
Author(s):  
MARA K. N. LAWNICZAK ◽  
DAVID J. BEGUN
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Sperm Competition ◽  
Competitive Ability ◽  
Recombinant Inbred Lines ◽  
Inbred Lines ◽  
Phenotypic Variance ◽  
Fitness Component ◽  
Male Sperm ◽  
Trait Locus

Sperm competition is an important fitness component in many animal groups. Drosophila melanogaster males exhibit substantial genetic variation for sperm competitive ability and females show considerable genetic variation for first versus second male sperm use. Currently, the forces responsible for maintaining genetic variation in sperm competition related phenotypes are receiving much attention. While several candidate genes contributing to the variation seen in male competitive ability are known, genes involved in female sperm use remain largely undiscovered. Without knowledge of the underlying genes, it will be difficult to distinguish between different models of sexual selection such as cryptic female choice and sexual conflict. We used quantitative trait locus (QTL) mapping to identify regions of the genome contributing to female propensity to use first or second male sperm, female refractoriness to re-mating, and early-life fertility. The most well supported markers influencing the phenotypes include 33F/34A (P2), 57B (refractoriness) and 23F/24A (fertility). Between 10% and 15% of the phenotypic variance observed in these recombinant inbred lines was explained by these individual QTLs. More detailed investigation of the regions detected in this experiment may lead to the identification of genes responsible for the QTLs identified here.

scholarly journals Male mating success and fertility in Drosophila melanogaster

1985 ◽  
Vol 46 (3) ◽  
pp. 279-285 ◽  
Author(s):  
Linda Partridge ◽  
Trudy F. C. Mackay ◽  
Susan Aitken
Keyword(s):  
Drosophila Melanogaster ◽  
Male Fertility ◽  
Significant Positive Correlation ◽  
Male Mating ◽  
Male Mating Success ◽  
Fitness Components ◽  
Mating Ability ◽  
Dominance Variation ◽  
Positive Correlations ◽  
Outbred Populations

SUMMARYThe male mating ability and male fertility of 40 third chromosome homozygote lines has been measured. There was significant between-line differentiation for both characters, and comparison with a heterozygous stock indicated inbreeding depression and hence dominance variation for them. The characters showed significant positive correlation both with each other and with other fitness components and total fitness, as measured by Mackay (1985). This pattern of large positive correlations between fitness components is not expected to occur in outbred populations.

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