Orientation sensitivity of the visual movement detection system activating the landing response of the blowflies,Calliphora, and Phaenicia: A behavioural investigation

The orientation sensitivity of the visual movement detection system relative to the axes of the eye was investigated for the landing response by changing the direction of movement of a periodic striped pattern (unidirectional movement) and a two-stripe pattern consiting of two stripes moving apart (bidirectional movement). In the momocular, equatorial regions of the eye progressive motion proves to be most effective, whereas in the frontal (equational), binocular region descendive motion is most effective in eliciting the landing response, probably caused by binocular interactions. A strong enhancement of the response is induced by stimulation in the binocular region of the two eyes. The orientation of elementary movement detectors relative to the axes of the ommatidial array is discussed. The findings are summarized in a functional model of the landing response.