Comparison of the Efficiency of three types of Canopy Traps on the Collection of Horse flies (Diptera: Tabanidae)

Abstract

Many different types of traps are used to monitor horse flies (Diptera: Tabanidae) throughout the world. Unfortunately, the hithertoo knowledge on the efficiency of traps is poor. Therefore, three new types of canopy traps have been evaluated, a standard trap and two modified ones, to determine their relative efficiency for collecting tabanids. Tabanids were collected with twelve traps at three different forest sites. One site was located in E' Croatia in the valley of the River Danube; two were located in the mountainous region of W' Croatia. The standard canopy traps collected significantly more tabanids than the smaller modified canopy traps. The size of the linen cover apparently influenced the collection efficiency. However, no significant effects were found between the modified high canopy traps. The highest efficiency of collections was recorded if the openings of the canopy traps were between 123 and 130 cm above ground. The standard canopy traps collected an average of 35 specimens per trapping period, whereas both modified high and small canopy traps collected 28 and 11 tabanids, respectively, per trapping period. The highest number of specimens and species was collected by the standard canopy traps. One may conclude that the designs of the three types of canopy traps affected the numbers of collected specimens and of species composition.