ISM, CNRS and Aix-Marseille Université, Marseille, France
Date(s) : 20/01/2021 iCal
14 h 00 min - 15 h 00 min
Recent studies carried out at our laboratory focused on gravity perception in hoverflies. Gravity perception in flying insects has mainly been studied in terms of grounded animals’ tactile orientation responses, but it has not yet been established whether hoverflies use gravity perception cues to detect a nearly weightless state at an early stage or even to stabilize their flight. Once dropped in free fall, hoverflies frequently initiated wingbeats but managed to avoid crashing only in variably structured visual environments . We have also shown that the position of the lighting (overhead or bottom lighting) significantly affected both the stabilization rates and the time taken by the flies to stabilize . Behavioural data have suggested that the vertical optic flow plays a key role in this anti-crash response. Free fall behavior analyses have also suggested that flying insect may not rely on graviception to stabilize their flight. Based on these two assumptions, we have developed a model which accounts for hoverflies ́ position and pitch orientation . Finally, I will present results and model about the righting reflex in hoverflies. It was observed here for the first time  that hoverfly reorientation is entirely achieved within 6 wingbeats (48.8 ms) at angular roll velocities of up to 10×10^3 deg s−1. The fundamental role of the halteres will be discussed.
 R. Goulard, J-L. Vercher and S. Viollet (2016), To crash or not to crash: how do hoverflies cope with free-fall situations and weightlessness?, J. of Experimental Biology, vol. 219, 2497-2503.
 R. Goulard, A. Verbe, J-L. Vercher and S. Viollet (2018), Contribution of the Dorsal Light Response to freely falling hoverflies’ flight stabilization strategy, Biology Letters, 14: 20180051.
 R. Goulard, J-L. Vercher and S. Viollet (2018), Modeling visual-based pitch, lift and speed control strategies in hoverflies, PloS Computational Biology, 4(1): e1005894.
 A. Verbe, L. Varennes, J-L Vercher and S. Viollet (2020) How do hoverflies use their righting reflex?, J. of Experimental Biology, vol. 223:jeb215327.