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

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 109; no. 29; pp. 11740 - 11745
• Main Authors: Gowaty, Patricia Adair, Kim, Yong-Kyu, Anderson, Wyatt W
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 17.07.2012; National Acad Sciences
• Series: From the Cover
• Subjects: adults; Alleles; Animal reproduction; Animals; Bias; Biological Evolution; Biological Sciences; Crosses, Genetic; dominant genes; Drosophila melanogaster; Drosophila melanogaster - physiology; Estimation bias; gender differences; Genetic Fitness - genetics; Genetic inheritance; Genetic loci; Genetic mutation; Genotype & phenotype; inheritance (genetics); Insects; loci; Male animals; Mating behavior; Mating Preference, Animal - physiology; Models, Biological; mutants; Mutation; parentage; parents; Phenotype; Phenotypes; progeny; Reproduction - physiology; Sex linked differences; Sexual Behavior, Animal - physiology; Sexual selection; variance; Viability
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.1207851109

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 or more 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.