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.