Flight control of fruit flies: dynamic response to optic-flow and headwind

Abstract

Insects are magnificent fliers that are capable of performing many complex tasks such as speed regulation, smooth landings and collision avoidance, even though their computational abilities are limited by their small brain. To investigate how flying insects respond to changes in wind speed and surrounding optic flow, the open-loop sensorimotor response of female Queensland fruit flies (Bactrocera tryoni) was examined. A total of 136 flies were exposed to stimuli comprising sinusoidally varying optic flow and air flow (simulating forward movement) under tethered conditions in a virtual reality arena. Two responses were measured: the thrust and the abdomen pitch. The dynamics of the responses to optic flow and air flow were measured at various frequencies, and modelled as a multicompartment linear system, which accurately captured the behavioural responses of the fruit flies. The results indicate that these two behavioural responses are concurrently sensitive to changes of optic flow as well as wind. The abdomen pitch showed a streamlining response, where the abdomen was raised higher as the magnitude of either stimulus was increased. The thrust, in contrast, exhibited a counter-phase response where maximum thrust occurred when the optic flow or wind flow was at a minimum, indicating that the flies were attempting to maintain an ideal flight speed. When the changes in the wind and optic flow were in phase (i.e. did not contradict each other), the net responses (thrust and abdomen pitch) were well approximated by an equally weighted sum of the responses to the individual stimuli. However, when the optic flow and wind stimuli were presented in counterphase, the flies seemed to respond to only one stimulus or the other, demonstrating a form of 'selective attention'.

Multisensory Control of Orientation in Tethered Flying Drosophila

“…The time constant of this decay was similar to the value we obtained by fitting our model. Summation of cues from different modalities has been proposed previously to explain stabilization reflexes [34,35] and forward velocity control [26,36,37] in flies and fish. Summation of visual and odor information has been observed in turning behavior of tethered flies [38], and in the turn probability of freely moving larvae [7].…”

Wing rapid responses and aerodynamics of fruit flies during headwind gust perturbations

“…Meanwhile, Engels placed bumblebees in heavy turbulence to observe the changes in their aerodynamic forces, moments, and flight power [23]. In addition, Lawson investigated the thrust and abdomen pitch of Queensland fruit flies in headwind [24]. In a different study, Ortega-Jimenez [25] even studied how turbulent convective flows impair the flight performance of Drosophila.…”

Retinal slip compensation of pitch-constrained blue-bottle flies flying in a flight mill

“…Visual control of forward flight in insects is commonly studied using flight tunnels in free-flight (David, 1982;Fuller et al, 2014;Serres et al, 2008;Srinivasan et al, 1996) or tethered-flight settings (David, 1978;Lawson and Srinivasan, 2017). Recent efforts by the authors also demonstrated the potential of using flight mills to study forward flight in semi-free settings with controlled flight conditions (Hsu et al, 2019).…”