Title: Revisiting an old question: Is the natural blend best for disruption of pheromone communication in moths? Author
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: April 12, 2013
Publication Date: April 22, 2013
Citation: Lapointe, S.L. 2013. Revisiting an old question: Is the natural blend best for disruption of pheromone communication in moths? [abstract]. Invited lecture, April 22, 2013, Cornell University, Geneva, New York. Technical Abstract: Short-lived microlepidoptera must, by force, be very good at finding their mate and reproducing. Insects are very good at this and moths, in particular, are highly evolved to use volatile signals (pheromones) to communicate and locate conspecifics. The chemical structures of many pheromones of moths have been elucidated, synthesized and used to control them. Mating disruption is achieved when a crop is sufficiently perfused with a synthetic pheromone that individual moths are unable to orient to the odor of the opposite sex. Many moth species produce a blend of volatile components. An old debate among practitioners of mating disruption is whether the ‘natural’ blend, i.e., that produced by a female moth, or an ‘unnatural’ or off-ratio blend of particular components is best to interfere with male orientation. Pheromone studies often seek to identify an optimal response (attraction or disruption of attraction) to continuously varied mixture components wherein proportionality of one component cannot be varied independently. We used geometric designs to systematically and efficiently explore the experimental space defined by pheromone amount and proportion for the citrus leafminer Phyllocnistis citrella, a major pest of citrus worldwide. Deployment of single sex pheromone components, either (Z,Z,E)-7,11,13-hexadecatrienal or (Z,Z)-7,11-hexadecadienal in citrus groves resulted in a high degree of disruption of attraction to the natural blend (3:1 triene:diene). The triene was approximately 13 times more effective compared with the diene alone. These results suggest a non-competitive model and support sensory imbalance as the mechanism of mating disruption in this species. The triene alone proved superior to the natural blend in disrupting trap catch. This talk will introduce the listener to the specific problem of the citrus leafminer and then describe the design of experiments to generate response surface models (RSM) that identify optimal responses to mixtures, an often-encountered problem in many areas of research. Given the experimental approaches employed for most moth species, it is not possible to conclude that optimal blends for disruption have been identified in most cases. If this approach were extended to more species, a more complete and possibly different understanding of mating disruption might emerge.