Gender based disruptive selection maintains body size polymorphism in Drosophila melanogaster

Handa, J. and Chandrashekara, K. T. and Kashyap, K. and Sageena, G. and Shakarad, M. N. (2014) Gender based disruptive selection maintains body size polymorphism in Drosophila melanogaster. Journal of Biosciences, 39 (4). pp. 609-620. ISSN 0973-7138

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Abstract

Darwinian fitness in holometabolous insects like the fruit fly Drosophila melanogaster is reported to be positively correlated with body size. If large individuals in a population have higher fitness, then one would expect directional selection to operate leading to uniformly large individuals. However, size polymorphism persists in nature and needs further probing. We assessed the effect of body size on some of the fitness and fitness-related traits in replicate populations of genotypically large, genotypically small and phenotypically small D. melanogaster flies. In this study, the time taken to attain reproductive maturity and copulation duration were independent of fly size. Fecundity and longevity of large females were significantly higher when they partnered genotypically small males than when they were with genotypically larger or phenotypically small males. The increased female longevity when in association with genotypically small males was not due to selective early death of males that would release the female partner from presumed cost of persistent courtship. On the contrary, the genotypically as well as phenotypically small males had significantly higher longevity than large males. The virility of the genotypically small males was not significantly different from that of genotypically large males. Our results clearly show that selection on body size operates in the opposite direction (disruptive selection) for the two genders, thus explaining the persistence of size polymorphisms in the holometabolous insect, Drosophila melanogaster.

Item Type:	Article
Uncontrolled Keywords:	nonhuman, animal, Animals, male, Male, female, Female, genetics, physiology, cytology, article, gender, fertility, reproduction, Genetic, Drosophila melanogaster, genotype, longevity, Longevity, phenotype, fitness, animal behavior, fly, polymorphism, Hexapoda, Sex Characteristics, sexual development, copulation, Copulation, Fertility, fecundity, body size, Body Size, Body Weights and Measures, courtship, diversifying selection, gender relations, Genetic Fitness, genetic selection, morphometrics, ovary, Ovary, reproductive fitness, Selection, sexual maturation, Sexual Maturation
Divisions:	Department of > Institution of Excellence
Depositing User:	Arshiya Kousar Library Assistant
Date Deposited:	03 Sep 2019 11:03
Last Modified:	03 Sep 2019 11:03
URI:	http://eprints.uni-mysore.ac.in/id/eprint/3496

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