Gene regulation linked to plasticity in queen weight and behavior reveals candidates for supergene-mediated genetic accommodation in the fire ant

ABSTRACT: In the fire ant Solenopsis invicta, a chromosomal inversion-derived supergene predicts gyne (pre-reproductive queen) weight and corresponding colony founding behavior. Inversion-carrying gynes are lightweight and depend on assistance from workers, meaning they must initiate reproduction in an already existing social group. Gynes that lack the inversion supergene are heavier and found colonies from scratch, relying on their own nutrient reserves to feed an initial brood. However, plasticity in gyne weight and life history also exists in fire ants, such as queen replacement, an alternative mode of dependent reproduction determined by gyne overwintering status. Like inversion-carrying gynes, overwintered gynes without the inversion supergene exhibit a lightweight phenotype and worker dependence. In gyne brains and ovaries, we compared transcriptional profiles of overwintered and non-overwintered gynes to reveal the gene regulatory changes associated with overwintering. We observed functional enrichment for several biological processes related to metabolism and behavior among these plasticity-associated differentially expressed genes. A comparison to genes differentially expressed by supergene genotype revealed significantly greater overlap than expected by chance in ovarian tissues. Moreover, some plasticity-associated genes were found to exhibit fixed allelic differences between inverted and non-inverted supergene variants that may contribute to observed differences in gene expression and physiology. Overall, our results are consistent with the hypothesis that a supergene modulates variation in social organization, in part, through increased genetic regulation of ancestrally plastic traits.

ORGANISM(S): Solenopsis invicta

PROVIDER: GSE253281 | GEO | 2025/01/06

REPOSITORIES: GEO