Causation, fitness effects and morphology of macropterism in Chorthippus parallelus (Orthoptera:Acrididae)

ABSTRACT. 1. Chorthippus parallelus (Zett.) displays an apparent‘flight polyphenism’despite the fact that macropterous individuals cannot fly. 2. Photoperiod is used as an environmental cue controlling the polyphenism: long day lengths increasing the proportion of macropterous adults. 3. Macropterous females start mating when older and are less fecund than brachypters. 4. In contrast to other studies the response may not be due to cues associated with a reduced environmental quality and we speculate that macropterism is not a dispersal mechanism in the Gomphocerinae.