Neural and non-neural contributions to sexual dimorphism of mid-day sleep in Drosophila: A pilot study

Abstract

Many of the characteristics associated with mammalian sleep are also observed in Drosophila, making the fruit-fly a powerful model organism for studying the genetics of this important process. Among these similarities is the presence of sexual dimorphic sleep patterns, which in flies, is manifested as increased mid-day sleep ( siesta) in males, compared to females. Here, we have used targeted miss-expression of the gene transformer (tra) and tra2 to either feminise or masculinise specific neural and non-neural tissues in the fly. Feminization of males using three different GAL4 drivers which are expressed in the mushroom bodies induced a female-like reduced siesta, while the masculinisation of females using these drivers triggered the male-like increased siesta. We also observed a similar reversal of sex-specific sleep by miss-expressing tra in the fat body, a key tissue in energy metabolism and hormone secretion. In addition, the daily expression levels of takeout, an important circadian clock output gene, were sexually dimorphic. Taken together, our experiments suggest that sleep-sexual dimorphism in Drosophila is driven by multiple neural and non-neural circuits, within and outside the brain.