AGGREGATION PHEROMONE OF CARPOPHILUS-ANTIQUUS (COLEOPTERA, NITIDULIDAE) AND KAIROMONAL USE OF C-LUGUBRIS PHEROMONE BY C-ANTIQUUS

Males of Carpophilus antiquus Melsheimer (Coleoptera: Nitidulidae) emit an aggregation pheromone that was found to be a novel hydrocarbon, (3E,5E,7E,9E)-6,8-diethyl-4-methyl-3,5,7,9-dodecatetraene, A synthetic scheme and spectra (mass and proton NMR) are given for the compound. Beetles produced the pheromone when feeding on a variety of media, including the brewer's yeast-based artificial diet, fermenting whole-wheat bread dough, corn, and prunes; live baker's yeast was generally added to the food media. Males held individually produced, on average, 25 x more pheromone per beetle than mares held in groups of 10 or more. Pheromone was not produced until males were at least 5 days old but was still detected from the oldest beetles tested (47 days). In field tests, the pheromone was attractive to both sexes of C. antiquus, and it was synergized by food volatiles: A combination of pheromone and fermenting whole wheat dough attracted 2.5x more beetles than pheromone alone, but dough by itself was not significantly more attractive than the control. Semiochemical interactions were studied among C. antiquus and two other sympatric species for which pheromones are known, C. lugubris Murray and C. freemani Dobson. C. antiquus responded readily to the pheromone of C. lugubris, but all other interspecific responses to the pheromones were weak. In a sample of naturally infested corn ears, the presence of C. antiquus was strongly associated with the presence of C. lugubris, as would be expected if the pheromone of C. lugubris serves as a kairomone for C. antiquus.