Figure 1: Contrast measured in chromatic and achromatic contrast mean “just noticeable differences” (JNDS) estimated for UV reflecting regions compared against adjacent non-UV reflecting patches as viewed by UV-sensitive models (open symbols) and VIS-sensitive models (filled symbols). Triangles indicate butterfly species and circles poison frog species. In nearly all species UV signals increase chromatic, but not achromatic contrast, but to differing degrees (see Table 1 for specific values and standard errors). Species in order of descending achromatic contrast: A = Heliconius melpomene plessen , B =Epipedobates tricolor Cielito, C = Eueides isabella , D =Heliconius melpomene agalope , E = Heliconius erato , F =Heliconius atthis , G – Ameerega bilinguis , H =Heliconius ismenius , and I = Oophaga sylvatica Lita (from Yeager and Barnett 2020). UV reflecting color pattern regions are shown in white in the silhouette illustrations below.