Fruit flies actively reset their own body clock
Your biological clock ticks around the clock, but what happens when it falls out of sync? Fruit flies turn out to actively reset it, and they do so by reshaping their environment. That is a striking new finding about how circadian rhythms are maintained.
The circadian rhythm (the internal biological clock that regulates the day-night cycle) is present in nearly all living organisms. Disruptions to it have been linked to accelerated ageing, impaired cognitive function, and higher risk of metabolic disease. The researchers report in Science that fruit flies do not passively wait for external light signals to reset their clock. Instead, they actively seek out the right environment to synchronise their rhythm.
Behaviour as part of the clock system
The flies adjusted their position based on the current phase of their internal clock, thereby generating the light exposure needed to keep it correctly set. The researchers call this proactive niche construction: the animal acts on an internal state to align its external environment with its biology.
This differs from the long-held assumption that environmental signals like light dictate the clock while the organism responds passively. The fly plays an active role. How that behaviour is orchestrated at the level of the brain remains to be fully explored.
Relevance for ageing and sleep
Circadian disruption increases with age. Older adults sleep less deeply, wake more often, and their internal clock drifts more easily. If actively seeking rhythm-supporting environments also matters in humans, it could point towards behavioural interventions. Deliberate daytime light exposure or avoiding blue light in the evening are examples already gaining attention.
The study was conducted in Drosophila, and translation to humans requires caution. But the core of the circadian system is highly conserved across evolution, which makes the insight scientifically relevant.
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