RESOLUTION OF PHEROMONE PULSES IN RECEPTOR-CELLS OF ANTHERAEA-POLYPHEMUS AT DIFFERENT TEMPERATURES

The ability of pheromone receptor cells of male Antheraea polyphemus ( Saturniidae) to resolve stimulus pulses was determined at different te mperatures (8 degrees, 18 degrees, 28 degrees C). The cells were stimu lated by repeated 20-ms puffs of the pheromone components (E,Z)-6,11-h exadecadienyl acetate and (E,Z)-6,11-hexadecadienal. At higher tempera tures, higher frequencies of stimulus pulses were resolved by the nerv e-impulse response: about 1.25 pulses per second at 8 degrees C, 2.5 p ulses/s at 18 degrees C and 5 pulses/s at 28 degrees C. The decreased ability of receptor cells to resolve stimulus pulses at low temperatur es may reduce the male moth's chance of reaching the pheromone source. The peak nerve-impulse frequency increased whereas the duration of ne rve-impulse responses to single stimulus pulses decreased at higher te mperatures. At a given temperature and stimulus intensity the peak ner ve-impulse frequency decreased with shorter intervals between the stim ulus pulses, but the duration of the responses remained almost constan t. The time needed for recovery from adaptation caused by a single sti mulus pulse was longer at lower temperatures. The aldehyde receptor ce ll recovered more quickly than the acetate cell. At low stimulus conce ntration, the resolution ability of the acetate cell was strongly decr eased, whereas in the aldehyde cell it was only slightly impaired.