Main trends in the ecological evolution of Diplopoda. All are life forms except for arboricoles. 1 stratobionts 2 trunk and crown arboricoles, as well as subcorticolous xylobionts 3 epiphytobionts 4 troglobionts 5 geobionts. NB: The thickness of numbered arrows roughly corresponds to the share of the respective ecological grouping along a gradient of biome succession with age (uppermost arrows, the gap between them indicates the primary subtropical biome whence developed all the main extant biomes). After Kime and Golovatch (2000). Drawing courtesy S. Dashdamirov.