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Bugs in the Christmas tree

December 18, 2012
University of Bergen
Your Christmas tree may be adorned with lights and glitter. But 25,000 insects, mites, and spiders are sound asleep inside the tree.

Your Christmas tree may be adorned with lights and glitter. But 25,000 insects, mites, and spiders are sound asleep inside the tree.

"There are a number of insects hiding in a Christmas tree," says Associate Professor Bjarte Jordal at the University Museum of Bergen, who goes on to list springtails, bark lice, mites, moths and the odd spider as the creeps most likely to be dragged into the average household come Christmas time.

Jordal is an expert on insects.

"In research on Christmas trees there have been found as many as 25,000 individual creep in some of the trees", Jordal explains. "If you pound the tree on a white cloth before you throw it out after Christmas, you will discover quite a number of small bugs."

How do these creeps end up in the Christmas tree?

"They go to sleep for the winter, or hibernate to use the technical term. They usually empty their bodies of fluids and produce a chilled liquid and are completely inactive. But they reawaken when the tree is brought into the heat of the living room. It’s all down to stimulus. Upon feeling the heat and awakened by the light, they believe that springtime has arrived and spring back to life."

So do they go about wandering around the living room or what?

"No, I believe they stay in the tree. Both the Christmas tree and the house itself will be very dry. Also, most insects don’t live off the tree, only in it. As they cannot feed on the limited plants found in most households, the bugs will quickly dry out and die. These insects and bugs do not constitute any risk or danger to people or furniture. And if anyone is worried about allergic reactions, I don’t think there’s any danger of that. But obviously, should there be an extreme number of mites in a tree people with severe allergies may react to this."

Are there a fixed number of bugs in each and every Christmas tree?

"This varies a lot. Some of it is down to pure coincidence and some of it is down to what type of tree it is. Trees chopped in your own backwoods will contain more bugs than firs and other trees that have been farmed for use as Christmas trees will contain fewer creeps. There is particularly much in Norwegian Pine, whereas Juniper shrub has a fauna of its own."

Can you spot the little beasts on the tree?

"No, they are good at hiding and are invisible to the human eye, although one certainly should be able to spot the odd spider. To get a proper look, you will have to get out a clean, white sheet and shake the tree."

What about the tabloid media’s favourite arachnids – the ticks? Can they be found in our Christmas trees as well?

"There may very well be, and the Norwegian Institute of Public Health has actually looked into this. Their research suggests that there are three reports every Christmas in Norway of ticks found in Christmas trees. What usually happens is that the family dog has gone to rest under the tree and has incurred ticks. But the overall chances of tick bites are minimal. Also, the dog need not be allowed to rest under the tree. And the ticks are usually in sleep mode when the tree is brought into the house and dead by the time the tree leaves the house after Christmas. So, as I said, the risk is minimal."

But even if there is seemingly little danger or nuisance to expect from these creepy-crawlies, what should people be conscious of to minimise the number of bugs in the Christmas tree?

"I would recommend that you get a locally grown hardwood tree, as this is most likely to have a limited fauna. But you should by no means clean or flush the tree free of bugs, as this will damage the tree. Anyway, there is nothing to fear. You need to take into consideration that there are plenty of insects and bugs in potted plants that are regular features in most households. As we all know, these attract plenty of flies. It’s no different with Christmas trees."

Do you think that people are aware that the Christmas tree they bring into the house is full of little bugs?

"Probably not. After all, these little bugs are invisible to the human eye. I believe there is a trend in people not being particularly knowledgeable about nature. But when you bring a tree into the comfort of your living room, the tree carries a part of nature with it. Yet at the same time people tend to remove themselves more and more from nature."

Story Source:

Materials provided by University of Bergen. Original written by Jens Helleland Ådnanes; translated from the Norwegian by Sverre Ole Drønen. Note: Content may be edited for style and length.

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University of Bergen. "Bugs in the Christmas tree." ScienceDaily. ScienceDaily, 18 December 2012. <>.
University of Bergen. (2012, December 18). Bugs in the Christmas tree. ScienceDaily. Retrieved May 19, 2024 from
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