Figure 2.

The relationship between residuals calculated from regressing surface area-specific cutaneous water loss against the torpor index of the bats and (a) the scores on the first principal component (PC1) denoting decreasing stratum corneum (SC) sphingolipid polarity, (b) the scores on the second principal component (PC2) denoting increasing (SC) sphingolipid chain length and (c) the scores on the third principal component (PC3). Plecotus christii (filled triangles) and Eptesicus bottae (filled circles) are the species found in arid and semi-arid habitats; Pipistrellus kuhlii (open circles) is the species found in both mesic and arid habitats in association with human settlements and Otonycteris hemprichii (open traingles) is the species that inhabits only hot, dry desert areas.