Colors Not Addressed to Us

Bees see from about 300 to 650 nanometres: ultraviolet is in, deep red is largely out. Many flowers carry patterns tuned to that range — dark ultraviolet centres, rings and lines running toward the nectar — invisible to us and blunt as road signs to them. Photograph a plain yellow rudbeckia through a UV filter and a bullseye appears in the middle, a target that has been there the whole time.

Even the parts we can see were not composed for our benefit. Red is common where birds do the pollinating and rare where bees do, because most bees cannot separate red from green foliage. White flowers that seem underdressed by day are often the night shift, working with moths and paying in scent rather than colour. Symmetry, landing-pad petals, a slight roughness for grip: all of it is furniture for a visitor the size of a thumbnail.

So a macro flower wallpaper is a piece of correspondence we have opened by accident, and it looks good anyway. The petal fills the frame at a scale no insect ever perceives, and the pattern that was meant to direct a landing now just organizes the composition. Not a bad second use for a message that was never sent to us.