Species-specific escape behaviour in grasshoppers

Abstract

A number of vertebrate species have been shown to flee at species-specific distances when approached by a predator but data on invertebrate escape behaviour are few. Grasshoppers are visually-orienting invertebrates that switch between walking when undisturbed to flying or jumping to flee from predators, thereby allowing the beginning and end of an escape attempt to be clearly defined. I studied the approach distances, escape distances, and angles of escape of nine sympatric species of acridid grasshoppers. Both approach distance and escape distance were correlated with each other and differed among species. Angle of escape showed no discernible trends. Within species some variation in escape behaviour was seen among sexes and colour morphs. The variation in escape behaviour among species was correlated with phylogeny but not with body size.