DIVERGENCE IN CUTICULAR HYDROCARBONS BETWEEN PARAPATRIC SUBSPECIES OFTHE MEADOW GRASSHOPPER, CHORTHIPPUS-PARALLELUS (ORTHOPTERA, ACRIDIDAE)

Two subspecies of the grasshopper Chorthippus parallelus (Orthoptera; Acrididae) meet and form a hybrid zone in the Pyrenees. Here we invest igate whether the subspecies differ in the blend of cuticular hydrocar bons. Such differences may function as chemical signals, being detecte d via contact chemoreception and used during mate choice as in other i nsects. Gas chromatography shows that the subspecies have diverged in the composition of their cuticular hydrocarbons. This difference betwe en subspecies exists over and above variation in cuticular hydrocarbon s among individual populations. The majority of tile difference can be attributed to the relative amounts of a small group of compounds pres ent in the cuticle. The possible consequences of this chemical diverge nce for mating encounters between the subspecies are discussed.