Do bugs sleep? It’s the sort of question that plagues a curious mind on the precipice of sleep, leaving you awake and confused as you stare at the ceiling trying to imagine a centipede getting into bed.

If you’re currently reading this at three in the morning and are eager to get back to sleeping yourself, the short answer is yes – but not all bugs sleep the same.

Do bugs sleep?

It’s perhaps first pertinent to touch on the definition of sleep, “a normal, reversible, recurrent state of reduced responsiveness to external stimulation that is accompanied by complex and predictable changes in physiology,” according to Britannica.

Sleep was first defined in insects by studies on fruit flies conducted back in 2000, reports PopSci, when two separate research groups found that sleeping flies were harder to frighten than awake ones.

This is true too of snoozing bugs like cockroaches, praying mantises, and bees, who will droop with gravity when catching some zees and have an “increased arousal threshold”. Adorably, cockroaches will even fold their antennae when they take a nap as a way to protect their delicate sensory organs while they snooze.

What happens during bug sleep?

Insects have a central nervous system, something that’s a key characteristic in “sleeping” organisms. Bugs also exhibit circadian rhythms, a pattern of sleep and wakefulness though the nature of that pattern changes depending on the species.

The existence of an internal circadian clock was first demonstrated in the cockroach Leucophaea maderae. Its cellular origins were then tracked down until, eventually, researchers were able to change a cockroach’s circadian rhythm by transplanting the specific part of the brain from a different roach that had been trained into a different sleep-wake cycle.

The circadian rhythms of foraging species like honeybees tend to see them get busy in the day and then rest at night. During rest, honeybees will move less, have decreased muscle tone, have a raised reaction threshold and their body temperature lowers – four features of sleep that are just like those of mammals and birds.

What happens if bugs don’t sleep?

Fruit flies have been found to exhibit something called “sleep rebound” in which deprivation leads to a greater need for sleep. Research has found that sleep-deprived flies would have to catch up on their zees, snoozing more than their well-rested counterparts.

Sleep deprivation has also been found to have a negative effect on honeybees in an experiment that kept bees awake using an “insominator” device, which used magnets to jostle bees trying to sleep. Those that were kept awake became lousy communicators, performing waggle dances about food sources with limited detail.

Are there bugs that don't sleep?

Proving the absence of sleep is a complex task, but there are certainly insects in which sleep hasn't yet been proven either. Butterflies, for example, are known to rest but as biologist at Oregon State University, Katy Prudic, told National Geographic, "we don't know if they sleep".

What we do know is that butterflies are one of several insects that will stop moving in very cold weather, a protective state known as torpor that is different from sleep. Bugs also hibernate as a way of surviving the winter, something that's seen in lady bird beetles.

So, curious minds can sleep sound in the knowledge that yes, bugs do snooze even if it doesn’t necessarily involve actually shutting any eyes.

But wait… do sharks sleep?!

All “explainer” articles are confirmed by fact checkers to be correct at time of publishing. Text, images, and links may be edited, removed, or added to at a later date to keep information current.