[Orientational behavior of the ixodid tick Hyalomma asiaticum under desert conditions].

The orientational behaviour of the imago of ticks in natural conditions is based on the optimal using of relatively primitive eyes with the development of a specific mechanism of orientation. A statistical study of tracks of ticks together with the analysis of the optical system and functional possibilities of the eyes have made it possible for the author to suggest a model of orientational mechanism based on different signal meanings of increasing and decreasing of light intensity registered by the eyes from the direction of their main optical axes.