Fig. 2

Phylogenetic relationship of Hymenoptera Or genes. a A maximum-likelihood tree of the 3330 Or genes from 9 hymenopteran species. Tree was made using RAxML under the model JTT and GAMMA correction. Node reliability was evaluated by 100 bootstrap replications. Grey dots indicate bootstrap values (>80) of each Or subfamily. Bootstrap values for nodes representing relationships among subfamilies are shown only if the value is higher than 70. Branches are colored according to species (Apis mellifera, light blue; Harpegnathos saltator, green; Cerapachys biroi, yellow; Linepithema humile, purple; Camponotus floridanus, black; Pogonomyrmex barbatus, blue; Solenopsis invicta, brown; Atta cephalotes, pink; Acromyrmex echinatior, red). A full tree with gene names and branch support is provided in Additional file 2. b Comparison of number of Or genes (only putative functional proteins) in each subfamily. Subfamilies that underwent sub-lineage expansion/contraction are highlighted in red