Erythrism

Erythrism is reddish pigmentation of hair, skin, feathers, or eggshells. It has been reported in rabbits, birds, dolphins, and insects.

Pictured above are fluorescent pink katydids photographed in upstate New York and Michigan.

Another nice example of erythrism

Previous examples here. This Chorthippus from Pixdaus, via Titam et le Sirop d'Erable.

Pink grasshopper

I presume this is a form of erythrism, though it is not defined as such in the Telegraph article.

Via NAACAL.