MALE-PRODUCED AGGREGATION PHEROMONE OF CARPOPHILUS-MUTILATUS (COLEOPTERA, NITIDULIDAE)

Males Of Carpophilus mutilatus Erichson produce an aggregation Pheromone to which both sexes respond. The pheromone includes two hydrocarbon components, (3E,5E,7E)-5-ethyl-7-methyl-3,5,7-undecatriene (1) and (3E,5E,7E)-6-ethyl-4-methyl-3,5,7-decatriene (2). These were emitted in a 10 : 1 ratio and in a total amount of ca. 5 ng per feeding male per day. All tested doses of 1 and 2, from 0.03 to 30 ng, were more attractive than controls in wind-tunnel tests, but there was no evidence of synergism between these trienes. Dramatic synergism between the pheromone and a food-type coattractant occurred in the field, however. In a date garden in southern California, traps with a combination of synthetic 1 and fermenting whole-wheat bread dough attracted 22 times more beetles than dough by itself and 295 times more than 1 by itself. Volatile collections from males also contained three oxygenated compounds that were absent from females. One of these was tetradecanal (ca. 5 ng per male per day), but the structures of the other two am presently undetermined (0.8 and 1. 1 ng per male per day). No function for these was demonstrated. One compound originating in the artificial diet, 2-phenylethanol, was particularly attractive in the wind-tunnel bioassay, as was the chromatographic solvent, methanol.