| Abstrakt: |
In the imagines of the mealworm Tenebrio molitor vigorous head movements during walk have been observed. This head waving is absent in resting animals. The time course of the head movement in the horizontal plane of the tethered animals was registered by means of a television camera and its power spectrum, autocorrelation function as well as the distribution of the head's angular position have been calculated. In non-homogeneous stationary panoramas, which are symmetrical with respect to the body axis the process governing the head waving is quasi-Gaussian, its power spectrum is a slowly declining exponential function of the frequency. In asymmetrical panoramas the distribution of the angular position of the head becomes also asymmetrical, and its average value is shifted with respect to the body axis. In homogeneously bright surroundings the process is the superposition of a quasi Gaussian and of a symmetrical periodic function, thus indicating a regular searching movement in addition to the random head waving. The possible role of the head waving for the fixation response is discussed. [ABSTRACT FROM AUTHOR] |
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