Figure 3.

Phylogenetic tree of the red palm weevil and other pest beetle gustatory receptors. Due to its large size, tree was divided into three parts: (a) bottom, (b) middle, and (c) top. A tree was reconstructed from protein sequences using the maximum likelihood approach by PhyML3.0. The carbon dioxide, sugar, and fructose receptor clades were highlighted. Tree was rooted at the CO₂ receptor clade. Branch supports were assessed using approximate likelihood-ratio test (aLRT); a value above 0.9 is shown with an orange dot on the node (Rfer = Rhynchophorus ferrugineus, Tcas = Tribolium castaneum, Dpon = Dendroctonus ponderosae, Ldec = Leptinotarsa decemlineata).