UPWIND FLIGHT OF PROSTEPHANUS-TRUNCATUS IS MEDIATED BY AGGREGATION PHEROMONE BUT NOT FOOD VOLATILES

Flight bioassays were carried out to investigate the response of Prost ephanus truncatus (Horn) (Coleoptera: Bostrichidae) to maize volatiles in comparison to the male-produced aggregation pheromone. Upwind attr action of flying P. truncatus is mediated by the male-produced aggrega tion pheromone. In contrast, beetles showed no response to maize grain s or volatiles, and no interactions between aggregation pheromone and maize volatiles were recorded. This absence of upwind flight to food v olatiles, or any synergism between pheromone and food volatiles sugges ts that the male-produced aggregation pheromone is the only known long -range semiochemical used by P. truncatus for dispersal and host-selec tion. These results are in contrast with those on several other stored -product species, and suggest that P. truncatus may not use maize vola tiles as long-range host finding kairomones in nature. We propose a hy pothesis for the process of dispersal and host colonisation by P. trun catus. (C) 1998 Elsevier Science Ltd. All rights reserved.