Creepy crawlies in the Christmas tree

Whether decked out with traditional straw goats, bling bling or children’s craft projects, every Christmas tree is decorated differently. However, all natural trees gracing our homes share one thing – their fauna.

Creepy crawlies in the Christmas tree

A spruce in the forest is a safe place to hibernate and live for many a tiny creature.

”The most typical inhabitants are psocids, a family of small, aphid-like insects who live in the tree throughout the year. Psocids feed on the fungi growing on the tree,” explains Professor Kari Heliövaara from the University of Helsinki.

Natural cones which may still be attached to the Christmas tree add even more specimens to this yuletide menagerie. The cones are often homes to cone bugs as well as the eggs, pupae and larvae of the cone pyralid and cone moth from the butterfly family. Meanwhile, their seeds may house spruce seed gall midges and spruce seed chalcids. The conifer may also play host to accidental tourists, small creatures such as spiders who have decided to overwinter in the tree.

Harmless visitors

Professor Heliövaara promises that these little stowaways can be found on all live Christmas trees.

”Most of the tree’s inhabitants will have dropped off on the way from the forest to the house,” he emphasises.

The fauna in domestic and imported trees is largely the same, although fir trees have some of their own dedicated species.

Imported trees carry slightly less fauna than domestic ones, as the long transport means more of the insects are shed than during the shorter domestic transports.

Once indoors, the warmth gradually wakes up the miniscule visitors. Insects which overwinter as eggs, pupae or larvae will grow to maturity within two or three weeks. Flying insects will seek out the light, and they can be easily spotted flying around lamps.

According to Professor Heliövaara, the inhabitants of the Christmas tree are harmless, and will not suck human blood or chew through supporting beams.

Occasionally bark beetles, typically recognised as pests, may find their way indoors during winter, but they arrive with firewood, not with a live Christmas tree.

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Text: Anu Vallinkoski
Photo: Sanna Agullana
21.12.2012
University of Helsinki, digital communications


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