title: Honeybees' speed depends on dorsal as well as lateral, ventral and frontal optic flows.
abstract: Flying insects use the optic flow to navigate safely in unfamiliar environments, especially by adjusting their speed and their clearance from surrounding objects. It has not yet been established, however, which specific parts of the optical flow field insects use to control their speed. With a view to answering this question, freely flying honeybees were trained to fly along a specially designed tunnel including two successive tapering parts: the first part was tapered in the vertical plane and the second one, in the horizontal plane. The honeybees were found to adjust their speed on the basis of the optic flow they perceived not only in the lateral and ventral parts of their visual field, but also in the dorsal part. More specifically, the honeybees' speed varied monotonically, depending on the minimum cross-section of the tunnel, regardless of whether the narrowing occurred in the horizontal or vertical plane. The honeybees' speed decreased or increased whenever the minimum cross-section decreased or increased. In other words, the larger sum of the two opposite optic flows in the horizontal and vertical planes was kept practically constant thanks to the speed control performed by the honeybees upon encountering a narrowing of the tunnel. The previously described ALIS ("AutopiLot using an Insect-based vision System") model nicely matches the present behavioral findings. The ALIS model is based on a feedback control scheme that explains how honeybees may keep their speed proportional to the minimum local cross-section of a tunnel, based solely on optic flow processing, without any need for speedometers or rangefinders. The present behavioral findings suggest how flying insects may succeed in adjusting their speed in their complex foraging environments, while at the same time adjusting their distance not only from lateral and ventral objects but also from those located in their dorsal visual field.
authors: Biorobotic Department, Institute of Movement Science, CNRS/Aix-Marseille II University, Marseille, France.
authors: Geoffrey
authors: G
authors: Portelli
authors: Franck
authors: F
authors: Ruffier
authors: Frédéric L
authors: FL
authors: Roubieu
authors: Nicolas
authors: N
authors: Franceschini
references: Annu Rev Neurosci. 2004;27:679-96
references: 15217347
references: J Exp Biol. 2005 Oct;208(Pt 20):3895-905
references: 16215217
references: J Exp Biol. 1999 Jun;202 (Pt 11):1481-90
references: 10229694
references: J Neurophysiol. 1998 Apr;79(4):1902-17
references: 9535957
references: Vis Neurosci. 1990 Apr;4(4):379-86
references: 2271450
references: J Physiol Paris. 2010 Jan-Mar;104(1-2):27-39
references: 19909808
references: J Exp Biol. 1999 Jun;202 (Pt 11):1491-500
references: 10229695
references: Rev Oculomot Res. 1993;5:239-63
references: 8420551
references: J Exp Biol. 2009 Apr;212(Pt 8):1120-30
references: 19329746
references: J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2010 Apr;196(4):307-13
references: 20217419
references: J Exp Biol. 2010 May;213(Pt 10):1625-32
references: 20435812
references: Curr Biol. 2007 Feb 20;17(4):329-35
references: 17291757
references: Naturwissenschaften. 2008 Dec;95(12):1181-7
references: 18813898
references: J Exp Biol. 1996;199(Pt 1):245-52
references: 9317729
references: PLoS Comput Biol. 2009 Nov;5(11):e1000555
references: 19893631
references: Philos Trans R Soc Lond B Biol Sci. 1951 May;235(625):163-290
references: 24541037
references: Proc Biol Sci. 2010 Apr 22;277(1685):1209-17
references: 20007175
references: Curr Biol. 2008 Apr 22;18(8):R320-3
references: 18430625
references: Vis Neurosci. 1991 May;6(5):519-35
references: 2069903
references: J Exp Biol. 2006 Mar;209(Pt 5):978-84
references: 16481586
references: Vision Res. 1986;26(1):161-79
references: 3716209
references: J Exp Biol. 1996;199(Pt 1):237-44
references: 9317712