Circadian rhythm of cat flea (Siphonaptera: Pulicidae) locomotion unaffected by ultrasound

Cat fleas, Ctenocephalides felis (Bouché), had a circadian rhythm of locomotion that peaked during the last 2 h of the photophase and declined to a lower level that was maintained throughout the scotophase. Activity was lowest during the first 8 h of photophase. The circadian rhythm of these fleas was not affected by an ultrasonic pest control device.