On the origin of pine sawflies caught in pheromone traps

Abstract:
This study investigated behaviour of male European pine sawflies, Neodiprion sertifer Geoffr. (Hym., Diprionidae), that were released downwind from pheromone traps. Releases were done at three distances; either at 5 m from one trap, or at 50 m or 200 m from five traps, placed in a line perpendicular to the current wind direction. As a control, males were released identically but without any pheromone source present. The behaviour of the males prior to take-off was studied on a release platform. The following different types of behaviour were recorded: grooming,

wing fanning, orientating and take-off. The frequency of grooming was significantly higher in the pheromone treatments compared to the control, whereas the frequency of wing fanning and orientating increased, although not significantly. The direction in which the males displayed

the various types of behaviour was more concentrated towards the wind when pheromone was present than during the control experiment. By colour marking of Ecology, Lund University, d travel speed could be calculated. The minimum recorded time from take-off to landing was 1 min, 6 min and 45 min for the 5 m, 50 m and 200 m experiments, respectively. The stimulation and attraction range of the trap was at least 200 m, and the sampling range after 24 hr was calculated to approximately 400 m (c.i. 140–1600 m).