|Tumlinson Iii, James|
Submitted to: Journal of Comparative Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/22/1995
Publication Date: N/A
Interpretive Summary: The tobacco budworm moth is an important pest of many crops including cotton. The sex pheromones produced by the females of this species to attract males have been identified and shown to have potential for use in integrated control programs. However, the natural pheromones are aldehydes, which are unstable in the field. Therefore a study of the neurophysiological receptors on the antennae of males, which detect the sex pheromones of the females, was conducted by scientists in the department of Zoology at the University of Trondheim in Norway, in cooperation with scientists at the USDA, ARS, Insect Attractants, Behavior and Basic Biology Research Laboratory in Gainesville, FL, to find new, more stable chemicals that could be used to attract these insects. Three different types of receptors were discovered, each responding to a different chemical or blend of chemicals. This information is useful in understanding how moths detect the chemical signals that are attractive to them and may eventually be used to develop new, more stable attractants for use in the field.
Technical Abstract: Single receptor cell recordings from the sensilla trichodea type 1 of the Heliothis virescens male antennae have revealed: (1) Three distinct types of receptor neurons, two previously identified types tuned to the principal pheromone components,(Z)-11-hexadecenal (Z11-16:AL) (79% of neurons recorded) and (Z)-9-tetradecenal (Z9-14:AL) (12%), and a third type (9%) that is tuned to (Z)-11-hexadecenyl acetate (Z11-16:AC). The acetate suppresses male attraction to conspecific females. (2) The Z11-16:AL receptor neurons respond with about equal frequency to the formate analogue, (Z)-9-tetradecenyl formate (Z9-14:FO) at comparable concentrations. The Z9-14:AL receptor neurons, however, show only weak responses to the corresponding formate (Z)-7-dodecenyl formate (Z7-12:FO). These results correlate well with results from field studies, showing that Z9-14:FO can substitute behaviourally for Z11-16:AL, whereas Z7-12:FO cannot substitute for Z9-14:AL. (3) The Z11-16:AC receptor neurons also respond to Z7-12:FO at higher concentrations. Therefore, Z7-12:FO would not be able to simulate the effect of Z9-14:AL, even at high concentration, because Z7-12:FO would mediate suppression of pheromone attraction through the Z11-16:AC neurons. (4) A difference in the interaction between the pheromone aldehydes and their membrane receptors is shown by the different effects of the two formate analogues.