PT  - JOURNAL ARTICLE
AU  - Perret, Jean-Luc
AU  - Guerin, Patrick M.
AU  - Diehl, Peter A.
AU  - Vlimant, Michéle
AU  - Gern, Lise
TI  - Darkness induces mobility, and saturation deficit limits questing
duration, in the tick <em>Ixodes ricinus</em>
AID  - 10.1242/jeb.00345
DP  - 2003 Jun 01
TA  - Journal of Experimental Biology
PG  - 1809--1815
VI  - 206
IP  - 11
4099  - http://jeb.biologists.org/content/206/11/1809.short
4100  - http://jeb.biologists.org/content/206/11/1809.full
SO  - J. Exp. Biol.2003 Jun 01; 206
AB  - The behaviour of Ixodes ricinus nymphs was recorded in 10-day experiments using computer-assisted video-tracking, in the absence of any host stimuli. These ticks switch spontaneously from questing in a desiccating atmosphere to quiescence in a water-saturated atmosphere after dark. Quantification of both questing and quiescence duration demonstrates that questing duration is inversely related to saturation deficit whereas quiescence duration is not. Distance walked after quiescence increased with desiccating conditions, while the distance walked after questing remained unchanged. Almost all locomotor activities of I. ricinus occurred during darkness under either a 14 h:10 h L:D or a 8 h:4 h L:D cycle. We established that all life stages of I. ricinus are equipped to sense shifts in light intensity with bilaterally placed strings of photoreceptors. This permits I. ricinus to use onset of darkness to trigger mobility when desiccation risk is reduced in nature.