The regulation of distance to dummy flowers during hovering flight in the hawk moth Macroglossum stellatarum

Abstract1.While collecting nectar in hovering flight the European hawk moth Macroglossum stellatarum efficiently regulates its distance relative to flowers that are shaken by wind. This can be demonstrated in laboratory experiments by moving dummy flowers (blue cardboard disks) towards and away from the feeding animal (Fig. 1).2.Distance regulation is predominantly mediated by visual cues. Mechanoreceptors on the proboscis appear to contribute little to the response.3.Movements of dummy flowers can be simulated by expanding and contracting a pattern projected onto a screen. With this technique we investigated the dynamical properties of the servo mechanism underlying distance regulation. The system behaves as a bandpass filter with corner frequencies of 0.15 and 5 Hz (Figs.2,3).4.When a high-speed ramp-like movement of the flower is simulated, there is an asymmetry in the response. During simulated approach the reaction is phasic-tonic with a pronounced overshoot at the beginning, during simulated retraction it remains tonic (Fig.5B,C).5.During distance regulation the animals compensate for the speed of the edge of the projected pattern. Distance regulation improves substantially when the number of stimulated elementary movement detectors is increased through increasing the number of contour lines by projecting concentric rings instead of a homogeneous disk (Figs.7, 8).

[1]  E. C. Sobel The locust's use of motion parallax to measure distance , 1990, Journal of Comparative Physiology A.

[2]  M Egelhaaf,et al.  Movement detection in arthropods. , 1993, Reviews of oculomotor research.

[3]  T. S. Collett,et al.  Relative motion parallax and target localisation in the locust, Schistocerca gregaria , 2004, Journal of Comparative Physiology A.

[4]  E. S. Eriksson Movement Parallax and Distance Perception in the Grasshopper (Phaulacridium Vittatum (Sjöstedt)): Short Communications , 1980 .

[5]  Thomas S. Collett,et al.  SHORT COMMUNICATION PEERING - A LOCUST BEHAVIOUR PATTERN FOR OBTAINING MOTION PARALLAX INFORMATION , 1978 .

[6]  B. Hassenstein,et al.  Systemtheoretische Analyse der Zeit-, Reihenfolgen- und Vorzeichenauswertung bei der Bewegungsperzeption des Rüsselkäfers Chlorophanus , 1956 .

[7]  T. Collett,et al.  Visual control of flight behaviour in the hoverflySyritta pipiens L. , 1975, Journal of comparative physiology.

[8]  Samuel Rossel,et al.  Binocular stereopsis in an insect , 1983, Nature.

[9]  D. Burkhardt,et al.  Zum binokularen Entfernungssehen der Insekten , 1973, Journal of comparative physiology.

[10]  D. Varjú Optomotorische Reaktionen auf die Bewegung periodischer Helligkeitsmuster , 1959 .

[11]  H Maldonado,et al.  Depth perception in the praying mantis. , 1972, Physiology & behavior.

[12]  W. Reichardt,et al.  Übertragungseigenschaften im Auswertesystem für das Bewegungssehen , 1959 .

[13]  F. A. Miles,et al.  Visual Motion and Its Role in the Stabilization of Gaze , 1992 .

[14]  Christian Wehrhahn,et al.  How is tracking and fixation accomplished in the nervous system of the fly? , 1980, Biological Cybernetics.

[15]  M. Srinivasan,et al.  Motion cues provide the bee's visual world with a third dimension , 1988, Nature.

[16]  Size of the binocular zone of the field of vision of insects , 1976 .