Do Wasps Sleep at Night?

Robert Pavlis

Wasps can be dangerous during the day, but what about at night? Do they sleep? Do they come out of the nest after dark? Are you less likely to get stung at this time of day? A better understanding of wasp activity at night will help you deal with nests.

ceramic figure, human head and body of a wasp
Let Sleeping Wasps Lie by Amber Aguirre, 2013 NICHE Awards Winner in ceramics

Do Wasps Sleep at Night?

A lot of sites say that wasps don’t sleep at night but that is a myth, although only a few wasp species have been tested, in part because it is very difficult to test them. They are just too small to hook up to a EEG (electroencephalogram) machine to measure sleep. There is also the problem of how do you define sleep? Sleep is a odd condition and without equipment it is even hard to tell if a human is sleeping. “Wasp sleep” might be quite different than “human sleep”.

Once inside the nest they are moving around, taking care of chores such as caring for larvae and making nest repairs. They also slow down and spend more time sitting still but you won’t find hundreds of them laying on their back, snoring loudly. They clearly do not sleep like humans.

A recent study, published by the University of Arizona, looked at 4 different species and found that they exhibited all of behaviors that define sleep; body and antennae lowered, lack of mobility, increased arousal threshold and inactivity. Even their body temperature drops 5 degrees F (2.5 degree C). Once in a sleep stage it was more difficult to reverse these conditions, a clear sign of being in a sleep-like state.

Microbe Science for Gardeners Book, by Robert Pavlis

This research shows that at least some wasps sleep and more than likely, other types do as well.

As a general background review of wasp facts have a look at Understanding Wasps – They Are Not Evil!

Do Wasps Come Out at Night?

As the sun goes down, wasps go into their nest and tend to stay there until sunup. That does not mean they won’t come out at night.

Some wasp species are nocturnal and have no trouble seeing in the dark. Many of these are parasitic and lay their eggs near or on night-feeding caterpillars and other hosts. Central and South America is home to a species of nocturnal wasp called Apioca that comes out on moonlight nights but they tend to stay in their nest on dark nights. The English hornet is active during the day or night.

Wasps prefer warmer temperatures and are less likely to venture out at night in spring or fall, and are more active at night in summer. Most will not fly properly below 50 F (10 C). If they do come out at night, they will usually fly towards light such as a street light, porch light or a lit window.

If you disturb a nest after dark they will come out to defend it. Wasps have no trouble flying at night, but most prefer not to.

What About Hornets?

Hornets are a special kind of wasp and many of these are active during the day and at night. They have optical adaptations, such as larger eyes, that let them see better in low light conditions and helps them fly in dim light. Hornets are also more likely to come out at night if you disturb the nest and then they will attack you.

I found no research about the sleeping habits of hornets. As a best guess they probably do sleep similar to the wasps that were tested.

Will Wasps Attack at Night?

Wasps don’t attack without provocation although some hornets don’t need much of a reason to attack. Most wasps don’t sting at all, and the few that do, will rarely sting you while in the garden if you are not near their nest. However, if you disturb their nest either during the day or at night, they will sting you. They are just slower at night because they have been sleeping and the temperature is lower.

Getting Rid of a Wasp Nest

There are many DIY solutions for getting rid of a wasp nest and most of them either work poorly, or not at all. For some of these see this post called 10 Wasp Myths That Will Surprise You.

The best way to deal with a nest is to wait until sun goes down when most of the wasps will be inside. Set up an optional flashlight a short distance from the nest. Wasps will head towards the light instead of yourself. Spray the opening with a commercial wasp-killing, knockdown spray. The wasps will try to exist the nest and be instantly killed. Destroy the nest the following day so that pupae do not reestablish it.

Getting rid of a nest like this is only required it it is near human activity. For ground nests, just mark the spot so people stay a few feet away. In no time at all a skunk or raccoon will dig it up and eat them. If the nest is in a tree, away from foot traffic – just leave it. Remember that wasps are a gardeners friend.

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Robert Pavlis

I have been gardening my whole life and have a science background. Besides writing and speaking about gardening, I own and operate a 6 acre private garden called Aspen Grove Gardens which now has over 3,000 perennials, grasses, shrubs and trees. Yes--I am a plantaholic!

4 thoughts on “Do Wasps Sleep at Night?”

  1. We live in a wooded area and put up with many nocturnal visitors to our outdoor lights. Visits by German hornets are scary, but in 10 years, we have avoided being stung and learned to see in the dark or use alternate entrances. During our first run in, I carried a wasp indoor after it landed in my hair. We managed to separate it and get it back outdoors. I hope they are really beneficial!

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  2. I have a ground wasp (yellow jacket) nest in my veggie garden every year and it’s not a huge garden but once I see where they are I can just put a tomato cage upside down around them to keep track and we don’t bother each other. There are a number of different kinds of yellow jackets though, and some are far more aggressive by nature than others. It’s the same with honey bees, so bee keepers would find that to be a familiar observation.

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    • I find the fake paper wasp nests available for purchase in season at hardware stores to be very effective. They will either prompt the wasps in an active nest to move elsewhere, or deter them from building a nest, which was my experience when I found a wasp at work in my small greenhouse. She (he?) had quite a few cells formed. But the fake nest soon changed the plan. I had wasps nesting under my deck, they left, but for a couple of years I hung the fake nest there in spring to prevent them from getting any ideas.

      Reply

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