Effect of color on the feeding preference of a generalist grasshopper, Acrida cinerea (Orthoptera: Acrididae)

The young leaves of many plant species exhibit red or purple coloration. It has been proposed that the red/purple coloration serves as a warning signal, indicating that defense chemicals against herbivores are highly concentrated in young tissues. In particular, it is expected that generalist herbivores will not like red/purple leaves because the chemical defenses developed by young leaves are generally more toxic or less nutritious to generalist herbivores than to specialists. To test this hypothesis, the color choices made by a generalist grasshopper, Acrida cinerea, were assessed using colored paper discs impregnated with feeding stimulants under three light conditions: white light, blue light, and darkness. Only under white light did A. cinerea eat less red paper and more yellow paper than green paper. They ate blue paper as well as green paper, indicating that they do not consider only green items to be food. These findings support that A. cinerea likely dislikes red foods not simply because red is different from the typical color of leaves but rather because red is a warning signal.