Influence of Wind on Hessian Fly (Diptera: Cecidomyiidae) Flight and Egglaying Behavior

Abstract

The influence of wind velocity on the behavior of ovipositing female Hessian flies, Mayetiola destructor (Say), was examined in a wind tunnel. Females exposed to wind speeds ranging from 0 to 2.0 m/s, tended to stay for longer on wheat, Triticum aestivum L., plants when the wind speeds experienced were higher, than when they were lower. However, although flight departing from plants was suppressed at higher wind speeds, on-plant behavior was not suppressed under these conditions. Thus, females that stayed longer on plants because of higher wind speeds laid more eggs per visit than females at lower wind speeds. Flight direction upon leaving a host plant was also influenced by wind. As winds increased >0.9 m/s, females no longer exhibited flights to upwind groups of wheat plants and were more likely to land in downwind groups of plants or to be blown out the end of the wind tunnel. When groups of females were released into host plant patches in low (0.1 m/s) or high (0.7 or 1.2 m/s) wind speeds, females in higher winds laid most of their eggs in the patches they were released into and in patches downwind of release patches. Alternatively, females in low winds laid eggs in upwind as well as downwind patches. In this experiment, the total number of eggs laid during the test period was greater in lower versus higher winds. The effects of the above responses to the reproductive biology of Hessian flies are discussed.