Related Experiment Video
Updated: May 27, 2026

Assaying Locomotor Activity to Study Circadian Rhythms and Sleep Parameters in Drosophila
Published on: September 28, 2010
Variability in circadian activity patterns within the Culex pipiens complex (Diptera: Culicidae)
Y Shinkawa1, S Takeda, K Tomioka
1Environmental Biology Laboratory, Yamaguchi University, Japan.
Abstract:
Circadian activity was compared among four strains of Culex pipiens molestus Forskal from Iran, Egypt, two localities (Ebira and Yanagawa) in Nagasaki, Japan, and one strain of Cx. p. pallens Coquillett from Japan. Under a 16:8 (L:D) h photoperiod, all the strains showed peaks of activity at lights on and off, with additional activity during both light and dark periods; Egyptian females and both sexes of Cx. p. pallens were inactive during the photophase. Under 0:24 (L:D) h, the length of the free-running activity period was significantly shorter in the "Iran" (21 h) than in the other three Cx. p. molestus strains (range, 21-23 h) and Cx. p. pallens (approximately 24 h). Under 24:0 (L:D) h, the activity rhythm was obscured. The length of the period was shorter in 24:0 (L:D) h than in 0:24 (L:D) h, violating Aschoff's circadian rule. Furthermore, the circadian peak did not always occur every day under 24:0 (L:D) h but rather exhibited "day-skipping."
Related Concept Videos
Biological Clocks and Seasonal Responses
Background and Environment Affect Phenotype
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
Circadian Rhythms and Gene Regulation
Circadian Rhythms and Gene Regulation
Chronopharmacokinetics: Circadian Rhythms and Influence on Drug Response
The time of drug administration is an important factor to consider, as it can influence the toxic dose of a drug. For example, a study conducted by Prins et al. in 1997 examined the effects of the timing of...

