No evidence of sexual selection in a repetition of Bateman's classic study of Drosophila melanogaster

• Type of Material: Article
• Authors: PA Gowaty, University of California, Los Angeles; Yong-Kyu Kim, Emory University; Wyatt W. Anderson, University of Georgia
• Language: English
• Date: 2012-07-17
• Publisher: National Academy of Sciences
• Publication Version: Final Published Version
• Copyright Statement: Freely available online through the PNAS open access option.
• Final Published Version (URL): http://dx.doi.org/10.1073/pnas.1207851109
• Title of Journal or Parent Work: Proceedings of the National Academy of Sciences
• ISSN: 0027-8424
• Volume: 109
• Issue: 29
• Start Page: 11740
• End Page: 11745
• Grant/Funding Information: National Science Foundation Grants IBN-9631801, IBN-0911606, and IOS-1121797 each provided partial support for the study.
• Keywords: Multidisciplinary Sciences; genetic parentage; Science & Technology - Other Topics; Science & Technology; monogamy; PRINCIPLES
• Research Categories: Biology, General; Biology, Genetics

Abstract

We are unique in reporting a repetition of Bateman [Bateman AJ (1948) Heredity (Edinb) 2:349-368] using his methods of parentage assignment, which linked sex differences in variance of reproductive success and variance in number of mates in small populations of Drosophila melanogaster. Using offspring phenotypes, we inferred who mated with whom and assigned offspring to parents. Like Bateman, we cultured adults expressing dramatic phenotypes, so that each adult was heterozygous-dominant at its unique marker locus but had only wild-type alleles at all other subjects' marker loci. Assuming no viability effects of parental markers on offspring, the frequencies of parental phenotypes in offspring follow Mendelian expectations: one-quarter will be double-mutants who inherit the dominant gene from each parent, the offspring from which Bateman counted the number of mates per breeder; half of the offspring must be single mutants inheriting the dominant gene of one parent and the wild-type allele of the other parent; and one-quarter would inherit neither of their parent's marker mutations. Here we show that inviability of double-mutant offspring biased inferences of mate number and number of offspring on which rest inferences of sex differences in fitness variances. Bateman's method overestimated subjects with zero mates, underestimated subjects with one ormore mates, and produced systematically biased estimates of offspring number by sex. Bateman's methodology mismeasured fitness variances that are the key variables of sexual selection.