Modulation of flight activity in Lobesia botrana Den. & Schiff. (Lepidoptera : Tortricidae) females studied in a wind tunnel

We studied modulations of flight activity in European grapevine moth female s (EGVM) by individual observations in a wind tunnel. The effect of differe nt factors was analyzed: variation in atmospheric pressure prior to the exp eriments, time of day, first experience of flight, age, mating, and odor of tansy, which attracts females. The circadian flight activity showed a peak the hour preceding the onset of scotophase and sustained activity occurred during the 6 h around this peak. Females with a flight experience in the t unnel took off more quickly than naive ones (3.9 +/- 7.4 vs 20.3 +/- 22.8 s ). Three-day-old unmated females subjected to negative variations of atmosp heric pressure (10 hPa) during the 4 h prior to the experiments increased t heir duration of flight (12.1 +/- 8.7 vs 5.3 +/- 3.4 s) compared to those n ot subjected to variation. One-day-old females were less active than older ones; flight was shorter than in 2-day-old females (2.7 +/- 6.7 vs 5.1 +/- 9.5 s) and fewer of them took off (28 vs 63%). Mating also affected the Fig ht activity of 2-day-old females; mated females flew longer than virgins (1 2 +/- 16.8 vs 5.1 +/- 9.5 s) and took off more quickly (6.5 +/- 14.4 vs 19. 3 +/- 20.1 s). Tansy odor in the tunnel did not significantly affect the fl ight behavior of virgin females, but it increased the proportion of mated f emales that initiated flight (87 vs 70%) and duration of flight (11.2 +/- 2 4.4 vs 7.2 +/- 13.7 s), and it reduced the latency to takeoff (2.1 +/- 7.4 vs 8.1 +/- 19.1 s). Flight duration in tansy odor was inversely correlated with the total number of eggs laid during the female's whole life. Our expe rimental settings did not allow observation of movements directed toward th e odor source.