Fig. 1

Phylogenetic relationships of 16 ant species studied shown with their pictures (source http://www.antweb.org/) and three biological traits: worker sterility (grey square, can lay unfertilized eggs; black square, completely sterile), colony queen number (grey square, single queen; black square, multiple queens), and invasiveness (grey square, not invasive; black square, can be invasive). The phylogenetic tree was constructed using OGG alignments with the software RAxML (v. 8) [87]. The data set contained 1427 genes and 3.59 Mb of sequence, and the analysis was partitioned by gene and conducted under a GTRGAMMAI model