Splitting of circadian rhythm ofmusca domesticaflies with azadirachtin

Abstract

The triterpenoid azadirachtin was injected in adult house flies and the effect on the circadian rhythm of locomotor activity studied. In most cases (83%) period was increased (by 0.4 h, as a mean), whereas flies injected with the solvent of azadirachtin, ethanol, increased period in 22% only (by 0.3 h, as a mean). In 46% of the azadirachtin injected flies a splitting of the activity rhythm into two components with the same period length was induced, whereas only one of the ethanol controls (2%) showed splitting after injection. LiCl added to the drinking water changed the activity pattern from splitting to arrhythmicity in about 50% of the azadirachtin treated flies.