A comparison of trap efficiency of window and Malaise traps
Two types of flight interception traps, window and Malaise traps, were placed in a transect at a forest edge from the ground up to the canopy at a height of 20 m. The window traps were significantly more efficient in catching the insect orders Thysanoptera, Mecoptera, Saltatoria, Coleoptera, Heteroptera, Psocoptera, Lepidoptera and the Araneae. The Malaise traps were significantly more efficient in catching the orders Diptera, Hymenoptera, Dermaptera and Strepsiptera. The catches in the window traps showed no trend with trap height above ground, whereas the numbers of insects caught in the Malaise traps decreased distinctly and continously with increasing height. The trapping difference between the two trap types cannot be explained with different reactions to the wind speed, but with the higher lateral light incidence in the upper traps, which allowed more insects to escape laterally. Therefore, Malaise traps seem not to be suited for quantitative sampling in exposed sites.