Dragonflies After Dark: Your Complete Guide
Dragonflies are easy to spot during the day as they zoom around in bright sunlight. But what do they do at night? Read on for the answers!
Dragonflies reduce their activity at night and hide from predators. They get slower and move less as the light fades. They settle into the protective shelter of plants, perch motionless, and hide until morning.
Nighttime changes the conditions in which dragonflies live and this makes a big difference in how they behave. Here is some more information about how and why dragonflies just hang out until dawn.
Do dragonflies sleep?
Dragonflies do “sleep” in a sense. They exhibit cyclical patterns of reduced activity during which their bodies perform important tasks, like injury repair. Dragonflies are daytime predators and most active during daylight and in warm temperatures. Their inactive period corresponds to the dark hours of the night, just like humans.
However, it is currently impossible to determine how equivalent dragonfly “sleep” is to human sleep.
Dragonflies don’t have eyelids to close and their eyes are fixed. They can’t demonstrate rapid eye movement (REM) like humans can. We can only guess about their sleep experience.
Also, dragonflies become lethargic as the temperature drops beyond what is comfortable for them. Therefore, it’s impossible to determine how much of a dragonfly’s stillness at night is because it’s sleeping versus a response to cooler nighttime temperatures.
Where do dragonflies sleep?
Dragonflies find sheltered spots to wait out the hours until morning. During the day, their primary defenses against predation are their fantastic vision and superb flying abilities. But these defenses fail during the night.
Dragonflies evolved superb vision but it depends on bright sunlight. They simply don’t see well in the dark. Plus, cooler nighttime temperatures decrease their mobility since dragonflies can manufacture only a tiny amount of their own body heat. They are at the mercy of ambient temperatures and need warmth to fly well. So they hide themselves as best they can in deep plant cover to avoid predators.
In addition, a dragonfly hides out for protection from the elements, especially rain and cold wind. As mentioned above, dragonflies become less able to fly quickly in colder temperatures. (Resh and Carde 2009) Hiding away at night is a good strategy to lessen the chances of becoming prey.
Do dragonflies fly at night?
Dragonflies go to ground at night for two main reasons.
First, dragonfly vision evolved to function well in bright sunlight. They see color and are fantastic at spotting motion. They rely on their excellent vision to spot prey and gauge distance when hunting during the day. This helps them not only catch food but also to avoid obstacles and spot predators that pose a danger.
During the day, a dragonfly is fast, agile and able to see its environment clearly. But they can’t see as well in the dark. Nighttime turns their daytime advantages into liabilities. Nocturnal predators find prey at night using senses other than vision so dragonflies would be easy targets.
Second, adult dragonflies are focused on two main priorities during their short life: hunting and reproducing. Successful hunting gives dragonflies the energy to grow robust enough to win mates and reproduce.
Dragonflies are incredible predators of flying insects like mosquitoes, beetles and flies during the day. But at night, most of their prey takes cover. So it makes sense for dragonflies to do the same. Resting when their prey rests conserves the dragonflies’ energy for the next day’s hunt, when their prey becomes active and vulnerable again.
What does it mean when you see a dragonfly flying at night?
Some dragonflies do fly at night. There are two hypotheses about why they do this.
The first hypothesis is what I call the “accidental” hypothesis. This guess supposes that something disturbed the insects and caused them to flee from their roosts. The dragonflies fly into the sphere of artificial light accidentally, but then can’t see well enough to dare flying back into the darkness.
This guess does make some sense. When startled, a dragonfly will naturally take flight. Because it sees best in daylight, it will fly towards the brightest light available, which at night could be a home’s flood light or a streetlight. Once in the sphere of artificial light, it could have a hard time getting itself out and back to safe cover in the darkness.
The second hypothesis gives dragonflies a lot more credit. This guess suggests that the dragonflies are flying at night deliberately, enticed to our artificial lights precisely because they attract moths. Dragonflies hunt flying insects. Moths certainly qualify as prey and are notorious for becoming trapped by artificial lights.
Such a situation could be a bonanza for bold dragonflies willing to take the risk of flying at night. Of course, free lunches don’t exist. Dragonflies who deliberately hunt at night run the same risk as the moths themselves. Namely, that hunting bats will put them on the menu.
What does it mean if you see a dragonfly on the ground at night?
A dragonfly hunkered down on a plant at night is resting to conserve energy, hiding to avoid discovery by predators and waiting for dawn to become active again.
Seeing a dragonfly at night on the ground can mean different things. One who fled its roost to escape an encroaching threat may crouch upright on the ground. It may not be able to see well in the dark and be hesitant to take off. Or it may be too cold to summon the energy to fly and must take its chances, exposed in the open.
A dragonfly upside down on the ground is either dead or very close to it, especially if the night is cool.
Dragonflies are vulnerable to temperatures that drop too quickly, too far, or remain too low for too long. Like all insects, dragonflies are ectothermic, meaning that their body temperature depends on the temperature of the air around them; dragonfly metabolism slows as the temperature drops.
During the day, dragonflies can protect themselves from cool temperatures to a certain degree by orienting their bodies and wings towards the sun (known as “basking”) or vibrating their wings (known as “wing whirring). (Resh and Carde 2009)
However, at night, they can rely only on whirring their wings to counteract the slowing effect of the cold temperatures. This behavior uses a huge amount of energy. A dragonfly that becomes too cold for too long can die.
The upside down position of a dead or stupurous dragonfly happens when the insect loses its grip on its perch and falls to the ground.
Are dragonflies attracted to lights?
Dragonflies seem disoriented if disturbed at night and will naturally fly towards light sources. But artificial lights shining in the darkness don’t tempt or trap dragonflies the way they do some nocturnal insects. While there are reports of dragonflies flying around lights at night, the behavior is not common.
However, one of my favorite dragonfly species, the Blue Dasher (Pachydiplax longipennis), does hunt moths at night around lights (Paulson, 2011).
Dragonflies are creatures of the daytime. They are at their best in warm, bright sunlight when their sharp vision and incredible flight speed and agility make them extremely successful predators within their niche.
Things change for dragonflies at night. They evolved to do the smart thing: rest, recover and hide from the enemies lurking in the dark.
Where to go next
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References
Paulson, Dennis. 2011. Dragonflies and Damselflies of the East. Princteton, NJ: Princeton University Press.
Resh, Vincent H., Carde, Ring T., Carde, Distinguished Professor and A M Boyce Chair in the Department of Entomology Ring T, and Card, Ring T, eds. 2009. Encyclopedia of Insects. San Diego: Elsevier Science & Technology.
