# Metabolism and behaviour: activity and sleep in flies

> Metabolism and behaviour are tightly linked: starved flies sleep less, and diet and gut microbes change activity and food choice.

Source: https://khushisingh.in/research/behaviour-and-metabolism/
Author: Khushi Singh (khushisingh.in). Licence: CC BY 4.0 for text and original illustrations, unless a credit says otherwise.
Evidence labels used on this site: established, strong evidence, emerging, hypothesis, debated. Where a page has Simple, Curious and Expert versions, all three follow.

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[Research](https://khushisingh.in/research/) · Ongoing · 2026–2027

Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany

Organism: [*Drosophila melanogaster*](https://khushisingh.in/research/model-system/#drosophila-melanogaster)

The question

How does an animal’s metabolism shape how much it moves and sleeps across the day?

Metabolism and behaviour are tightly linked: starved flies sleep less, and diet and gut microbes change activity and food choice. Alongside my work on chromatin in the embryo, I measure the activity and sleep of adult fruit flies with Drosophila Activity Monitor (DAM) assays, to ask how metabolism shapes daily behaviour.

[The basics: food for genes](https://khushisingh.in/explore/07-food-for-genes/)

## In short

Flies sleep: still periods of five minutes or more come with a higher arousal threshold and are regulated much like sleep in mammals (Shaw et al. 2000; Hendricks et al. 2000). (evidence: established) Sleep and activity also respond to metabolism; starved flies, for example, sleep much less (Keene et al. 2010). (evidence: strong evidence) This makes behaviour a sensitive, whole-animal read-out of metabolic state, and a link to my work on [metabolism and chromatin](https://khushisingh.in/research/gut-to-germline/).

## How a DAM assay works

**How a DAM assay is set up.** Each fly lives in its own small glass tube, with food at one end. An infrared beam crosses the middle of the tube; every time the fly walks through it, the monitor adds one count, and the counts are saved every minute, for days, in an incubator with controlled light and temperature (Pfeiffenberger et al. 2010). Schematic, drawn for this site.

*[Here the web page has an interactive activity; open the source URL to use it.]*

From the minute-by-minute counts I calculate total activity, total sleep, the number and length of sleep bouts, activity during waking minutes, and how these change between day and night. Kept in constant darkness, the same recordings show the fly’s internal circadian rhythm (Pfeiffenberger et al. 2010).

A single beam only sees the fly when it crosses the middle of the tube, so small movements elsewhere can be scored as sleep. Monitors with several beams, or video tracking, give finer detail (Garbe et al. 2015). (evidence: strong evidence)

Status: ongoing

This work is unpublished, so this page describes the technique only: **no fly lines, conditions or results** are shared until the work is published.

## Methods used

- Drosophila Activity Monitor (DAM) assays
- Sleep and circadian analysis
- Fruit-fly genetics

[What these methods are →](https://khushisingh.in/research/toolbox/)

## References

1. Pfeiffenberger C, Lear BC, Keegan KP, Allada R (2010) Locomotor activity level monitoring using the Drosophila Activity Monitoring (DAM) system. Cold Spring Harbor Protocols 2010:pdb.prot5518. [doi:10.1101/pdb.prot5518](https://doi.org/10.1101/pdb.prot5518)
2. Shaw PJ, Cirelli C, Greenspan RJ, Tononi G (2000) Correlates of sleep and waking in Drosophila melanogaster. Science 287:1834–1837. [doi:10.1126/science.287.5459.1834](https://doi.org/10.1126/science.287.5459.1834)
3. Hendricks JC, et al. (2000) Rest in Drosophila is a sleep-like state. Neuron 25:129–138. [doi:10.1016/S0896-6273(00)80877-6](https://doi.org/10.1016/S0896-6273(00)80877-6)
4. Keene AC, et al. (2010) Clock and cycle limit starvation-induced sleep loss in Drosophila. Current Biology 20:1209–1215. [doi:10.1016/j.cub.2010.05.029](https://doi.org/10.1016/j.cub.2010.05.029)
5. Garbe DS, et al. (2015) Context-specific comparison of sleep acquisition systems in Drosophila. Biology Open 4:1558–1568. [doi:10.1242/bio.013011](https://doi.org/10.1242/bio.013011)