# A supergene controlling social structure in Alpine ants also affects the dispersal ability and fecundity of each sex

## TL;DR

A genetic supergene in Alpine ants controls social organization and also affects how well individuals can disperse and reproduce.

## Contribution

The study shows a supergene directly influences dispersal traits and fecundity in both sexes of ants.

## Key findings

- The M haplotype increases dispersal potential and fecundity in both sexes.
- Queens and males with the P haplotype have reduced dispersal abilities and lower fecundity.
- Supergenes are linked to social polymorphisms and sex-specific traits in ants.

## Abstract

Social organization, dispersal and fecundity coevolve, but whether they are genetically linked remains little known. Supergenes are prime candidates for coupling adaptive traits and mediating sex-specific trade-offs. Here, we test whether a supergene that controls social structure in Formica selysi also influences dispersal-related traits and fecundity within each sex. In this ant species, single-queen colonies contain only the ancestral supergene haplotype M and produce MM queens and M males, while multi-queen colonies contain the derived haplotype P and produce MP queens, PP queens and P males. By combining multiple experiments, we show that the M haplotype induces phenotypes with higher dispersal potential and higher fecundity in both sexes. Specifically, MM queens, MP queens and M males are more aerodynamic and more fecund than PP queens and P males, respectively. Differences between MP and PP queens from the same colonies reveal a direct genetic effect of the supergene on dispersal-related traits and fecundity. The derived haplotype P, associated with multi-queen colonies, produces queens and males with reduced dispersal abilities and lower fecundity. More broadly, similarities between the Formica and Solenopsis systems reveal that supergenes play a major role in linking behavioural, morphological and physiological traits associated with intraspecific social polymorphisms.