Bateman's Data: Inconsistent with “Bateman's Principles”

• Main Authors: Thierry Hoquet, William C. Bridges, Patricia Adair Gowaty
• Format: Article
• Language: English
• Published: Wiley 2020-10-01
• Series: Ecology and Evolution
• Subjects: Bateman (1948); sex differences; sexual selection; variance in number of mates; variance in reproductive success
• Online Access: https://doi.org/10.1002/ece3.6420

Abstract A.J. Bateman (1948) hypothesized that a metric of sexual selection is in sex differences of intrasexual variance in number of mates (VNM). AJB predicted that (a) males have greater variance in reproductive success (VRS) than females; (b) males have greater VNM than females; and (c) a positive relationship between VNM and VRS is stronger among males. AJB used phenotypically observable mutations in offspring to identify parents and to count subjects' NM and RS. AJB's conclusions matched his predictions, later called “Bateman's Principles.” Empirical challenges to his conclusions guided analyses herein. (a) AJB's analysis pseudo‐replicated sample sizes, violating a sexual selection assumption: That is, individuals must be in the same population to choose and compete. (b) AJB's methods overestimated subjects with no mates while underestimating subjects with one or more. (c) A replication (Gowaty et al., 2012) showed that offspring inheriting nametags from both parents often died before expressing adult phenotypes, proving some of AJB's methods produced biased data. Science historian Thierry Hoquet located AJB's archived, handwritten laboratory notes, photocopied, and transcribed them. We tested each of the 65 unique populations for expected combinations in offspring of parental mutations: 41.5% failed Punnett's tests: Offspring carrying nametags simultaneously from both parents were missing showing estimates of parents' NM and VNM were undercounted. 58.5% of populations met Punnett's expectations providing an unparalleled opportunity to re‐evaluate AJB's predictions. 34 unbiased populations had no sex differences in VRS; 37 had no sex differences in VNM. No sex differences in slopes of RS and NM occurred in any unbiased population. Regressions showed weak, positive, significant associations between VNM and VRS for females and males, contrary to AJB's prediction that the relationship would be positive in males but not in females. AJB's laboratory data are inconsistent with “Bateman's Principles.”