Fig. 1

Phylogeny, dating and gene family evolution of S. aterrima (Sate A), S. pratorum (Sate B) with other insect species. (a) the dated tree and orthologue statistics. Branch length represents divergence time (unit, 100 Mya); numbers on the branches represent gene families expanding/contracting/rapidly evolving. “1:1:1” represents shared single-copy orthologues, “N: N:N” represents multicopy orthologues shared by all species, “Chironomidae” represents orthologues unique to Chironomidae, “Species-specific” represents Species-specific genes, “others” represents unclassified orthologues and “unassigned” represents orthologues that cannot be assigned to any orthogroups. (b, c) Significantly expanded gene families (orthologue numbers ≥ 10) in SateA(b) and SateB (c)