Fig. 3From: Diversification of the ant odorant receptor gene family and positive selection on candidate cuticular hydrocarbon receptorsEstimation of gene gain and loss events and number of Or genes in ancestral species. Number of gene gains and losses are shown on tree branches and indicated with+ and −, respectively (blue BadiRate, red NOTUNG). Numbers in square boxes indicate number of Or genes in ancestral and extant species. The phylogeny of 7 ants and a honey bee (Ap. mellifera) with approximate divergence times (in million years: MY) is inferred from references [2, 62, 63]Back to article page