Data from: The interplay of biotic and abiotic factors in shaping genetic variation at 6Pgdh in the bulb mite

The polymorphism of 6Pgdh in the bulb mite Rhizoglyphus robini involves
two alleles, S and F, which have opposing effects on male reproductive
success. While S-bearing males have a reproductive advantage and the S
allele fixes in the laboratory populations, polymorphism is regularly
observed in natural populations. We hypothesize that the 6Pgdh
polymorphism in the bulb mite may be maintained by context-dependent
selection, driven by fluctuations of temperature and sexual selection
intensity, as predicted by balancing selection models based on
genotype-by-environment interactions. This study uses experimental
evolution to track allele frequency changes over 13 generations under
different temperatures (12°C and 18°C) and sexual selection intensities
(equal and female-biased sex ratios). The results show a significant
increase in F allele frequency under higher sexual selection intensity at
12°C. This suggests that individuals with the F allele gain reproductive
advantage at lower temperatures, and 6Pgdh polymorphism may be maintained
through a three-way interaction for fitness between genotype, abiotic
environment (temperature), and biotic environment (sex ratio). In
addition, in a direct assay of male reproductive success across
temperatures, we did not detect differences between genotypes. This
suggests that the allele frequency shifts observed in the experimental
evolution may not be explained solely by reproductive competition, but
could also involve selection acting on survival or other fitness
components. The complex interplay between environmental factors and
demographic dynamics in shaping allele frequencies highlights that
multiple factors can interact in maintaining polymorphism, potentially
through context-dependent selection.