Data from: Multiple forms of balancing selection maintain inversion polymorphism

Despite many examples of balanced inversion polymorphisms, little is known
about how they affect fitness-related traits. This knowledge gap hampers
our understanding of how they are selectively maintained as protected
polymorphisms. Here, we study the effects of a cosmopolitan balanced
inversion polymorphism in D. melanogaster, In(3R)Payne, on fitness
components, including traits related to development, growth, reproduction,
stress resistance, and adult survival. We find that the non-inverted
standard (STD) chromosomal arrangement and the inverted (INV) arrangement
behave like Mendelian alleles of a supergene, which affect a suite of
complex fitness-related phenotypes. While the STD arrangement tends to
have positive, mostly dominant effects on size-related traits, fecundity,
fertility, stress resistance, and lifespan, the INV arrangement exhibits
mostly recessive effects that are indicative of fitness costs. Yet, in
favor of the balanced polymorphism, we observe overdominance for egg
hatchability, egg-to-adult survival, pupal survival at 18°C, developmental
time, and male desiccation resistance. The most parsimonious explanation
for these heterotic effects is that they are due to some form of
multi-locus heterokaryotype advantage. We also find several instances of
trait-, sex-, and temperature-dependent changes in the degree of
dominance, suggesting a possible role of antagonistic selection with
context-specific dominance reversals in maintaining the polymorphism.
Moreover, genotype-by-environment interactions and parental effects appear
to contribute as well. Together, our results suggest that multiple
phenotypic modes of balancing selection are involved in maintaining the
inversion polymorphism.