O Christmas Tree, O Christmas Tree How lovely are thy insects

December 15th, 2023
A brown ladybug

Every Christmas the stories resurface: supposedly about 25,000 creatures are living in your Christmas tree. Exactly how much of this is true and which insects can actually be found? Naturalis' insect expert Aglaia Bouma can tell you more.

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The skeleton
of an ecosystem

The figure of 25,000 is not plucked out of thin air. It is taken from a study by Norwegian researcher Bjarte Jordal. During his research on Norwegian Christmas trees, he found spruces and pines in which as many as 25,000 insects, spiders and other crawlers lived. Similar research has not (yet) been done in the Netherlands, but the fact that all sorts of creatures can be found in your Christmas tree is inevitable. " All kinds of things always live in and around trees. Indeed, different species of plants and animals depend on them" says Aglaia. "The same goes for Christmas trees. So when you bring them into your home, you bring in the 'skeleton' of an entire ecosystem."

Christmas trees in a forest

A warm
Christmas

One insect that likes to spend the winter in Christmas trees is the Black-stem aphid (Cinara confinis). Branch aphids are aphids that are not limited to just the leaves, but also suck sap from branches, twigs and roots, among others. In fresh trees, the sap keeps flowing, but in Christmas trees (especially those that have been cut down), the sap runs out. The aphids become hungry and start looking for food. On top of that, eggs may have been laid on the needles. The warmth of your home gives the nymphs the idea that spring has arrived, and they hatch their eggs. They, too, cannot find enough food in the tree. "You don't have to fear the Black-stem aphid," Aglaia says. "The insects stay in or under your tree. They are looking for sap from the tree and since they can't find it, they will unfortunately die."

A black-stem aphid on a branch

An array
of arthropods

Other Christmas guests are the bugs, for example Phytocoris intricatus. This insect hibernates in spruce trees and lays its eggs there as well. As with the Black-stem aphid, these bugs think spring has begun due to the warmth of your living room. As a result, the larvae crawl out of their eggs. Again, a lack of food will keep the insects from surviving.

"And there are many other arthropods that might occur," says Aglaia. Think of bark beetles, ladybugs, spiders, mites, springtails, (parasitic) wasps or, for example, the green stink bug. Aglaia finds the latter insect special: "In summer they are bright green, but in winter they are brown and almost invisible against the trunk of a (Christmas) tree." The green stink bug does not shed its skin, but changes color, "That way it adapts optimally to the season."

The tales that there would also be ticks in your Christmas tree are scaremongering, according to Aglaia: "In very exceptional cases there could be one in your tree, but that chance is very small."

Een sparrenspillebeen op een naaldboom
Groene schildwants

A white
sheet

There's not much you can do about the bugs in your tree, and there's no need to. Aglaia: "After all, you're bringing in not just a tree, but an entire ecosystem." If you would like to limit the number of bugs in your Christmas tree, you can pat out the tree outside before bringing it inside. "But be sure to put a white sheet under it," Aglaia says. "That way you can get a good look at what creatures are living in your tree. That's not only incredibly interesting, but also very educational."

What kind of insect
is that?

Have you found interesting, beautiful or strange insects in or under your Christmas tree? And would you like to know which insects they are? Then bring them to Naturalis on December 30, 2023 or January 2, 2024. Aglaia Bouma and fellow insect expert Jan Wieringa can be found in the LiveScience hall preparing insects and examining your Christmas insects. Keep an eye on the calendar for more information.

A beetle

More
information

In her book Huisgenoten: insecten in en om je eigen huis (2023, Atlas Contact), Aglaia Bouma tells you all about the insects that live in and around your home.
https://www.atlascontact.nl/boek/huisgenoten/ 

Source image Black-stem aphid: Roy Kleukers