Hungry Flies Feeding on a Food Patch (image) Cell Press Share Print E-Mail Caption Hungry flies feeding on a food patch show graded responses to a repetitive, overhead shadow stimulus. Moving from left to right, the three images show flies' positions after, respectively, 0, 3, and 5 passes of the shadow stimulus. Credit William T. Gibson and David J. Anderson Usage Restrictions Credit Required. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.