Fig. 1

Maximum Likelihood Phylogeny Based on the Protein Sequences of the Candidate ORs. Red: H. cichorii (Hcic); blue: H. phaleratus (Hpha); black: T. castaneum (Tcas); turquoise: D. ponderosae (Dpon); and grey: A. planipennis (Apla). The tree is based on MAFFT alignment, was constructed using RAxML, and was rooted with the conserved lineage of Orco proteins. The coloured dots indicate nonparametric bootstrap support (%): red: ≥ 75, yellow: 50–74, and black: < 50. Two major Hycleus expanded clades are evident (red arc). The red asterisk (*) marks the positively selected gene pairs