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Accession Number:
ADA399861
Title:
Flight Behaviour of Cadra Cautella Males in Rapidly Pulsed Pheromone Plumes
Descriptive Note:
Corporate Author:
CALIFORNIA UNIV RIVERSIDE DEPT OF ENTOMOLOGY
Report Date:
2002-01-01
Pagination or Media Count:
22.0
Abstract:
Airborne pheromone plumes in wind comprise filaments or odour interspersed with gaps of clean air. When flying moths intercept a filament, they have a tendency to surge upwind momentarily, and then fly crosswind until another filament is intercepted. Thus, the moment-to- moment contact with pheromone mediates the shape of a flight track along the plume. Within some range of favourable interception rates, flight tracks become straighter and are headed more due upwind. However, as the rate of interception increases, there comes a point at which the moth should not be able to discern discreet filaments but, rather, should perceive a fused signal. At the extreme, homogeneous clouds of pheromone inhibit upwind progress by representative tortricids. In a wind tunnel, Cadra cautella Walker Lepidoptera Pyralidae were presented with 10 ms pulses of pheromone at a repetition rate of 5,10,17, and 25 1, and a continuous, internally-turbulent plume. Pulse size and concentrations were verified with a miniature photoionization detector sampling surrogate odour, propylene, at 100 Hz. Male moths maintain upwind progress even at plumes of 25 filaments s1 Furthermore, moths exhibited greater velocities and headings more due upwind at 17 and 25 Hz than at the lower frequencies or with the continuous plume. It is hypothesized that either C. cautella possesses a versatile sensory system that allows the resolution of these rapidly pulsed pheromone plumes, or that this species does not require a flickering signal to fly upwind.
Distribution Statement:
APPROVED FOR PUBLIC RELEASE
