What is "erythrism"

Erythrism \E*ryth"rism\, n. [Gr. 'eryqro`s red: cf. F. ['e]rythrisme.] (Zo["o]l.) A condition of excessive redness. See Erythrochroism.

n. (context biology English) Abnormal red colouration.

Erythrism or erythrochroism refers to an unusuaI reddish pigmentation of an animaI's fur, hair, skin, feathers, or eggshells.

Causes of erythrism include

• genetic mutations which cause an absence of a normal pigment and/or excessive production of others
• diet, as in bees feeding on "bright red (colored) corn syrup" used in maraschino cherry manufacturing

Erythrism in katydids has been occasionally observed. The coloring might be a camouflage that helps some members of the species survive on red plants. There is also consensus that the erythristic mutation is actually a dominant trait among katydid species, albeit a disadvantageous one, due to the overwhelmingly green coloration of most foliage. Hence, most pink or otherwise vividly colored katydids do not survive to adulthood, and this observation explains their rarity.