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Electrophysiological investigations of pheromone-sensitive sensilla in the hybrids between two mMoth species

Auteurs : Renou (Michel), Gadenne (Christophe) et Tauban (Dominique)


Année de publication : 1996
Publication : Journal of Insect Physiology
Volume : 42
Fascicule : 3
Pagination : 267-277


Résumé :

Thirteen pheromone compounds or pheromone analogues were screened on the antennal trichoid sensilla of males in French populations of Agrotis ipsilon, Agrotis segetum and in hybrids between female ipsilon and male segetum produced in the laboratory. Six functional types of trichoid sensilla were identified. Type 1 sensilla were characterized by the presence of a single receptor cell tuned to Z7-12:Ac. Type 2 sensilla housed two pheromone receptor cells. One cell was tuned to Z5-10:Ac; the other cell was less specifically tuned to Z8-12:Ac and showed various levels of responses to Z5-12:Ac, Z5-10:OH, Z11-16:Ac and Z11-16:Ald. The receptor neurones in type 3 sensilla responded to Z5-12:Ac. Type 4 sensilla contained a neurone tuned to Z9-14:Ac and Z9-12:Ac. Only one sensillum in A. ipsilon was found to house a receptor cell responding to Z9-12:Ac (type 5). Finally, neurones in type 6 sensilla did not respond to any of the compounds. The pheromone detection systems of parent species and hybrids were compared. The main difference between the two species was the distribution of type 1 and 2 sensilla. Type 1 sensilla were the most numerous (61.5%) and were found mainly on the branches of the antenna in A. ipsilon and the first generation hybrids. On the contrary, type 2 sensilla were more abundant (61.3%) in A. segetum where they stood principally on the antennal branches. Type 3 sensilla were present only in A. segetum and the hybrids, while type 4 sensilla were found only in A. ipsilon and the hybrids. Concerning cell specificity and sensillum distribution, the pheromone detection system of hybrids was very close to that of A. ipsilon. A. segetum is known for geographic variability in its communication system and a comparison is made with other