Circadian Rhythm of Temperature Preference and Its Neural Control in Drosophila

Abstract

A daily body temperature rhythm (BTR) is critical for the maintenance of homeostasis in mammals. While mammals use internal energy to regulate body temperature, ectotherms typically regulate body temperature behaviorally [1]. Some ectotherms maintain homeostasis via a daily temperature preference rhythm (TPR) [2], but the underlying mechanisms are largely unknown. Here, we show that Drosophila exhibit a daily circadian clock dependent TPR that resembles mammalian BTR. Pacemaker neurons critical for locomotor activity are not necessary for TPR; instead, the dorsal neuron 2s (DN2s), whose function was previously unknown, is sufficient. This indicates that TPR, like BTR, is controlled independently from locomotor activity. Therefore, the mechanisms controlling temperature fluctuations in fly TPR and mammalian BTR may share parallel features. Taken together, our results reveal the existence of a novel DN2- based circadian neural circuit that specifically regulates TPR; thus, understanding the mechanisms of TPR will shed new light on the function and neural control of circadian rhythms.

The Pyrexia transient receptor potential channel mediates circadian clock synchronization to low temperature cycles in Drosophila melanogaster

“…We were therefore surprised that pyx mutant showed normal entrainment in the 25-298C interval and that we identified a third temperature range for this channel (16-208C). Temperature preference behaviour also has a clock-controlled circadian component (temperature preference rhythm, or TPR), whereby the preferred temperature gradually increases during the day, reaching almost 278C in the evening [27]. It will be interesting to see whether Pyx is required for TPR.…”

Temperature sensation in Drosophila

“…At the circuit level, innocuous cooling stimulates dopaminergic neurons 23 and dopaminergic signaling in the mushroom bodies is critical for cool avoidance 24 , suggesting that cool-sensing and warmth-sensing both act through modulating dopaminergic signaling in the mushroom bodies. As thermal preference exhibits circadian variation, input from the circadian clock may also interact with these pathways 25 .…”

Studying circadian rhythms in Drosophila melanogaster

“…In mammals, the circadian clock in the brain orchestrates behavioral, hormonal and other physiological rhythms throughout the body [1]. In Drosophila , it gates eclosion and courtship, determines the period of rest and activity, the timing of feeding and influence temperature preference [2, 3]. Besides controlling various behaviors, the Drosophila circadian clock also coordinate many rhythms in peripheral organs, such as olfactory and gustatory sensitivity rhythms [4, 5], and the mitotic response of gut stem cells to damage [6].…”