Frames 443 (top) and 456 show M. microtis flapping its wings while hovering over a dragonfly. Derived from data (M. microtis 17th March run 3) collected by the ChiRoPing Project (Ref. 12), used with permission.
Difference image produced by subtracting frames 449 from 451 and displaying the absolute value of the difference. The movements of the bat and the dragonfly wing over 4 ms are evident.
Model of reflection from static dragonfly wing and deflected wing attached to dragonfly body D. T/R with beam pattern generates acoustic emission and detects echo that follow the path indicated by a solid line from a normally-incident section of at range . Echo produced by a normally-incident section of at r′, indicated with a dashed line, returns later and has a smaller amplitude.
Experimental configuration. Common Baskettail (Epitheca (Tetragoneuria) cynosura) specimen with 15 cm wing span mounted on a large plastic leaf. Second leaf forms clutter echo at closer range. T/R, air brush A, dragonfly-in-clutter complex consists of clutter leaf C, reflecting wing W, and supporting leaf .
Echo waveforms. (A) Echo from planar surface. (B) Echo from complex with in the resting state. Spacing between vertical lines corresponds to a 19 mm range increment. (C) Echo from the complex with maximum deflection. Dashed lines indicate a shift in W echo of 9.6 μs. (D) 80 echoes from the complex over two periods of solenoid actuation with 5 ms effective sampling period.
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