Influence Of the Daily Light Cycle on the Behavior of Argas Cooleyi (Acarina: Argasidae)

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Abstract
Responses to the daily light cycle can explain several facets of the behavior of Argas cooleyi under natural conditions. Experiments showed that unfed ticks have a negative photo response to undirected light and a negative klinotaxic orientation to directed light. A low thigmokinesis operates in response to substrate or mechanical stimulation. These responses appear to keep ticks hidden during daylight hours. Unfed A. cooleyi have an exogenously controlled diurnal locomotor rhythm synchronized to occur while swallows are roosting. This behavior apparently releases the low thigmokinesis and permits nightly host-finding activities in unfed ticks. Alteration of the LD cycle causes a corresponding shift in the locomotor rhythm and the rhythm does not persist in constant darkness. A low ambient temperature (15/C) suppresses the rhythm, but does not eliminate it. Water balance lias no apparent influence on the rhythm.