ABSTRACT

Comprehensive knowledge of the chemical ecology of the boll weevil, especially with regard to the production of and response to pheromone, is critically important to continued efforts to improve pheromone traps, lures, and the interpretations of trapping data. In light of recent reports demonstrating a strong correlation between weevil accessory gland condition and pheromone production, existing dissection data from trapping studies implied that at least some trap-captured weevils were capable of continued pheromone release. Thus, the possibility of weevils continuing to release pheromone in traps was investigated by monitoring pheromone production by individual weevils following their removal from food. Pheromone production during the 24-h collection period immediately prior to food removal averaged 46 µg. Of the 13 pheromone-producing weevils, 12 weevils continued to release pheromone during first 24-h starvation period, but the average pheromone production level during this period dropped to 10 µg. During the second day of starvation, only 5 weevils continued to release pheromone and average daily pheromone production was reduced to 3 µg. In comparison, daily pheromone production by weevils with continued access to food varied little throughout the study period. These results clearly demonstrate that pheromone-producing weevils can continue to release pheromone in the absence of a host. This previously unrecognized capability could represent an important source of variation in trapping studies, particularly those involving comparisons of traps or lures.