The importance of pattern in visual attraction of Tabanus nigrovittatus Macquart (Diptera: Tabanidae)

Abstract

Host-seeking female Tabanus nigrovittatus Macquart primarily use visual cues to locate hosts and host mimics. The importance of various attributes of patterns to this behavior was examined in the field using black and white two-dimensional panels. Panels with a square, circle, or star of equal size were equally attractive as were panels with stars with increasingly complex edges. In a series of panels with black circles of increasing size, attraction increased as the size of the circles increased. High contour density was not important in series of panels with increasing size and decreasing number of patterns (squares or circles), and large patterns with simple edges were most attractive. Both light objects against a dark background and dark objects against a light background were highly attractive. The response of flies to objects with stripes indicated that stripes decreased attraction, possibly as a result of shape disruption. These results indicate that solid, compact, large objects with high contrast against the background were the most attractive to host-seeking flies and that fine pattern detail was not important.