The influence of evaporated pheromone upon the trapping of the spruce bark beetle – Ips typographus (L.) (Coleoptera: Curculionidae: Scolytinae) – Short communication

This article examines the relative efficacy of releasing a larger pheromone plume volume and the relative efficacy of the number of pheromone dispensers within baited traps in trapping the spruce bark beetle. Pheromone plume is released from a standard pheromone dispenser, and a higher volume of pheromone was provided by an increased number of pheromone dispensers. A field trial with 30 pheromone baited traps was conducted in 2013 that used three dispenser variants over ten replications. Ten traps were baited with one pheromone dispenser, ten with two dispensers and ten with three dispensers. The pheromone dispensers were placed according to EPPO standard PP1/152(4) in a fully randomized design. The highest trapping was achieved by the variant using three pheromone dispensers, and the lowest trapping was achieved by the two pheromone dispenser variant. There was no statistically significant difference between the three variants. The results suggest that the efficacy of pheromone traps cannot be increased solely through an increase in the number of pheromone dispensers.

Contextual Chemical Ecology: Male to Male Interactions Influence European Corn Borer1 Male Behavioral Response to Female Sex Pheromone in a Flight Tunnel

The responses of European corn borer, Ostrina nubilalis (Hübner), males in a flight tunnel to sex pheromone, [11-tetradecenyl acetate (97:3, Z:E)] was dependent upon the context in which the males were exposed to the stimulus. Males, held individually in isolation before being exposed to pheromone, flew upwind in the pheromone plume and landed on the pheromone source significantly more often than males caged with other males before exposure to the pheromone. When groups of males were simultaneously exposed to female sex pheromone, they responded, on a permale basis, with significantly more upwind flights to pheromone and intense behavior near the pheromone source than did males exposed to the pheromone individually. Heightened intensity of male response in group flight was independent of whether the males were individually isolated or caged with other males before being exposed to the pheromone. The enhanced behavioral output of males responding to pheromone in groups may represent an evolutionary adaptive advantage in instances where several males are simultaneously pursuing a single calling female.