Olfactory sensitivity of gomphocerine grasshoppers to the odours of host and non-host plants

Abstract

Antennal responses to host and non-host odours were recorded, using the electroantennogram technique, from four gomphocerine grasshoppers with different feeding habits: Bootettix argentatus (monophagous on Larrea, a dicotyledonous plant), Ligurotettix coquilletti (oligophagous on dicotyledonous plants), Cibolacris parviceps (polyphagous) and Chorthippus curtipennis (graminivorous). The patterns of responses across the plant odours were similar for all four grasshopper species, but there was a relatively greater response to the odour of Larrea in B. argentatus and L. coquilletti which specialise on this plant. This suggests that there is considerable overall similarity in the make up of the olfactory receptor populations of these four grasshoppers species, but that some specificity for hostplant odour does exist at the antennal level. Resume Sensibilite olfactive d'orthopteres Gomphocerinae a l'odeur de plantes hotes et non hotes Les reponses antennaires ont ete examinees par electroantennogramme aux odeurs de plantes hotes et non hotes d'orthopteres Gomphocerinae de comportements alimentaires differents: Bootettix argentatus, monophage sur une dicotyledone, Larrea; Ligurotettix coquilletti, oligophage de dicotyledones; Cibolacris parviceps, polyphage; Chorthippus curtipennis, graminivore. Les types de reponse des quatre especes etaient tres voisins, mais les reponses aux odeurs de Larrea de B. argentatus et L. coquilletti, specialistes de cette plante, etaient relativement plus fortes. Ces resultats suggerent une similarite globale considerable dans la composition des populations de recepteurs olfactifs de ces quatre especes d'orthopteres mais aussi une certaine specificite pour les odeurs de la plante hote au niveau antennaire.