DNA methylation and expression of the egfr gene are associated with worker size in monomorphic ants

Abstract

AbstractThe reproductive division of labour is a hallmark of eusocial Hymenoptera. Females are either reproductive queens or non-reproductive workers. In ants, workers often display further task specialisation that is associated with variation in size and/or morphology. Because female polyphenism is typically under environmental control, it is thought epigenetic mechanisms (such as DNA methylation) play a central role since they mediate gene-by-environment interactions. Methylation of the growth-promoting geneepidermal growth factor receptor(egfr) was indeed shown to control worker size in a highly polymorphic ant. However, it remains unknown ifegfrmethylation could also regulate worker size in monomorphic species. By combining experimental pharmacology and molecular biology, we show that worker size is associated withegfrmethylation in two monomorphic ants. Furthermore, we functionally demonstrate that EGFR signalling affects worker size. These results indicate that worker size regulation byegfrmethylation has been mechanistically conserved in ants but remains unexploited in monomorphic species.