Fig. 1

Phylogenetic tree of the odorant receptor (OR) family. The receptor sequences included were from Dendroctonus ponderosae (Dpon, red), Agrilus planipennis (Apla, blue), Anoplophora glabripennis (Agla, green), and Tribolium castaneum (Tcas, orange). The tree is based on a MAFFT alignment, constructed using PhyML, and rooted with the conserved lineage of Orco proteins. Numbers at nodes indicate aLRT (approximate Likelihood Ratio Test) SH (Shimodaira-Hasegawa)-like branch support, calculated using PhyML. For clarity, exact support values are only shown for major branches and if > 0.7, whereas support for all branches are indicated by the colored circles; support increases with the size and brightness of the circles. The red arcs indicate the nine major coleopteran OR groups as defined in [53]. To reduce tree size, the massively expanded T. castaneum-specific OR-lineages in former OR groups 5 and 6 [54] are here represented by 10 ORs each, which together with the former OR group 4 were recently combined into subfamily 5A [53]. The sources of sequence data and explanation of receptor suffixes are detailed in the Methods section