|Groot, Astrid -|
|Blanco, Carlos -|
|Classen, Alice -|
|Inglis, Ollie -|
|Santangelo, Richard -|
|Lopez, Juan DE Dios|
|Heckel, David -|
|Schal, Coby -|
Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 15, 2010
Publication Date: September 28, 2010
Citation: Groot, A.T., Blanco, C.A., Classen, A., Inglis, O., Santangelo, R.G., Lopez, J., Heckel, D.G., Schal, C. 2010. Variation in sexual communication of the tobacco budworm, Heliothis virescens. Southwestern Entomologist. 35:367-372. Interpretive Summary: Tobacco budworm is an important pest of cotton and although use of Bt cotton has decreased the importance of this pest recently, diligence in Bt resistance monitoring in still considered of major concern. Sex pheromone trapping continues to be a major component of Bt resistance monitoring so research on the chemical-based sexual communication in this pest species is important. Research indicated no variation in sex pheromone composition related to the host plant from which the insects were collected and significant effects of the ratios of the two major sex pheromone components on the number of males captured in traps. These results are important in the use of sex pheromone baited traps to monitor this pest in different geographical areas of the Cotton Belt where use of Bt cotton varieties is becoming the dominant management approach for this pest.
Technical Abstract: Females of the tobacco budworm, Heliothis virescens (F.), exhibit distinct geographical and temporal variation in sex pheromone composition, but the causes and significance of this variation are largely unexplored. Here we assessed whether 1) female pheromone variation was related to the host plants of origin, and 2) pheromone lures with varying amounts of Z9-14:Ald or 16:Ald were differentially attractive to males. Variation in female pheromone did not seem to be related to the host plants from which eggs or larvae were collected, which may be because field-collected larvae were reared for three to five larval stages on artificial diet. By varying the concentration of Z9-14:Ald within the range in the female pheromone gland, we found males were more attracted as the amount increased from 1 to 10% relative to Z11-16:Ald, but significantly less with the highest concentration of 25%. In contrast, with 16:Ald, similar numbers of tobacco budworm males were caught in all traps where 16:Ald ranged from 0 to 200%. These results show that variation in Z9-14:Ald but not 16:Ald is evolutionarily significant and likely subject to stabilizing selection in the field.