RESUMO
The effects on olfaction of N-ethylmaleimide (NEM), a specific reagent of free sulfhydryl groups, were studied in the moth Mamestra brassicae. The antennae of male M. brassicae bear two types of specialist receptor neurons involved in pheromone communication. One type is tuned to (Z)-11-hexadecenyl acetate (Z11-16:Ac), the main pheromone component; the second type is tuned to (Z)-9-tetradecenyl acetate (Z9-14:Ac), an interspecific inhibitor not produced by the females of this species. Vapours of NEM irreversibly inhibited the electro-antennographic (EAG) responses to Z11-16:Ac and Z9-14:Ac. When Z11-16:Ac was applied before and during NEM treatment, the responses to Z9-14:Ac were preserved and some protection was observed in the responses to Z11-16:Ac. In return, Z9-14:Ac partially prevented the disappearance of responses to Z11-16:Ac but not to Z9-14:Ac. A third compound, hexadecyl acetate (16:Ac), found in the pheromone gland, but not detected by the antennal receptors, did not prevent the inhibition caused by NEM.
