Geographic variation in amounts of the aggregation pheromone 4,8-dimethyldecanal produced by males from North American populations of red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae)

The red flour beetle, Tribolium castaneum, is a serious pest of stored products world-wide.  Feeding males release an aggregation pheromone, 4,8-dimethyldecanal, DMD, that is attractive to both sexes.  Previous studies quantified the amount of DMD produced over a given amount of time, but there was substantial variation among these studies in the quantities of DMD reported.  In the work discussed here we used a consistent and reliable method to collect volatiles from individual feeding males on the solid-phase absorbent Poropak-Q, followed by quantitative analysis of DMD with gas chromatography-mass spectrometry.  The amount of DMD produced by individual males from 10 geographically separate populations of T. castaneum was determined.  We found that amounts of DMD released varied from less than 30.0 ng/male/day in beetles from Manitoba and Georgia, to over 150 ng/male/day in beetles from Kansas, Alabama, and California.  Males within the same population showed slight variations in the amount of DMD produced.  Within the Winnipeg and Georgia populations DMD production ranged from 13.2 to 52.5 ng/male/day and from 0 to 58.4 ng/male/day respectively.  The Kansas, Alabama, and California populations had ranges of DMD production that were 62.4 to 347.5 ng/male/day, 3.3 to 316.9 ng/male/day, and 31.4 to 379.9 ng/male/day respectively.  Our results suggest that pheromone production in T. castaneum varies significantly among geographically separate populations. Controlled mating with high-producing and low producing males suggest that pheromone production and release is probably controlled by multiple genes.