Figure 4. Emergence and extinction of insect glycerol transporters.

Schematic overview of aquaglyceroporin (Glp) and entomoglyceroporin (Eglp) evolution in relation to the divergence times of Arthropoda, with multiple terminal branches representing the genomic copy number. Entwined blue and magenta lines indicate incomplete lineage separation of Prip and Eglp genes, while green dotted lines indicate putative loss of Glps. Arthropod divergence times are based on molecular estimates38,53, with dashed lines indicating uncertain age. Two saltatory events (vertical arrows on inferred paleoclimate) are highlighted in the early Ordovician and Carboniferous periods, when Elgps respectively evolved from Aqp4-related Prip orthologs and were subsequently positively selected in the last common ancestor of the Holometabola. The inferred paleoclimate and icehouse episodes are redrawn from 5/10 detrended running means of δ¹⁸O calcitic shells44. Np, neoproterozoic; Cm, Cambrian; Or, Ordovician; S, Silurian; De, Devonian; Ca, Carboniferous; Pe, Permian; Tr, Triassic; Ju, Jurassic; Cr, Cretaceous; Pg, Paleogene; N, Neogene. Values in the abcissa are millions of years before present.