New paper:
Hesselberg, T. and Lehmann, F.-O. (2009) The role of experience in flight behaviour of Drosophila.Journal of Experimental Biology 212, 3377-3386.
The paper is from postdoc in the BioFuture Research Group of Fritz-Olaf Lehmann at the University of Ulm in Germany. I was there from 2006 to 2007, but due to delays with analysing the data and writing-up as well as a tough review process the paper is first out now.
The paper can be accessed here if you have an institutional licence. Other interested are welcome to contact me for a copy.
Abstract
Experience plays a key role in the acquisition of complex motor skills in running and flight of many vertebrates. To evaluate the significance of previous experience for the efficiency of motor behaviour in an insect, we investigated the flight behaviour of the fruit fly Drosophila. We reared flies in chambers in which the animals could freely walk and extend their wings, but could not gain any flight experience. These naive animals were compared with control flies under both open- and closed-loop tethered flight conditions in a flight simulator as well as in a free-flight arena. The data suggest that the overall flight behaviour in Drosophila seems to be predetermined because both groups exhibited similar mean stroke amplitude and stroke frequency, similar open-loop responses to visual stimulation and the immediate ability to track visual objects under closed-loop feedback conditions. In short free flight bouts, peak saccadic turning rate, angular acceleration, peak horizontal speed and flight altitude were also similar in naive and control flies. However, we found significant changes in other key parameters in naive animals such as a reduction in mean horizontal speed (–23%) and subtle changes in mean turning rate (–48%). Naive flies produced 25% less yaw torque-equivalent stroke amplitudes than the controls in response to a visual stripe rotating in open loop around the tethered animal, potentially suggesting a flight-dependent adaptation of the visuo-motor gain in the control group. This change ceased after the animals experienced visual closed-loop feedback. During closed-loop flight conditions, naive flies had 53% larger differences in left and right stroke amplitude when fixating a visual object, thus steering control was less precise. We discuss two alternative hypotheses to explain our results: the `neuronal experience’ hypothesis, suggesting that there are some elements of learning and fine-tuning involved during the first flight experiences in Drosophila and the `muscular exercise’ hypothesis. Our experiments support the first hypothesis because maximum locomotor capacity seems not to be significantly impaired in the naive group. Although this study primarily confirms the genetic pre-disposition for flight in Drosophila, previous experience may apparently adjust locomotor fine control and aerial performance, although this effect seems to be small compared with vertebrates.
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