- Praying mantises lay egg cases (oothecae) outdoors in late summer or fall.
- Christmas trees are grown on outdoor farms, so branches can already have egg cases attached.
- The ootheca looks like a small brown, foamy, walnut-shaped lump, which is easy to miss.
- When the tree is brought indoors, the warmth can trigger early hatching.
Is it dangerous?
- ❌ Not dangerous to people or pets
- ❌ Not harmful to the tree
- ⚠️ Impractical indoors: the babies will scatter and won’t survive long without food
What to do if you find one
- Do not panic
- Clip the branch holding the egg case
- Place it outside on a tree, shrub, or sheltered garden spot
- This allows the mantises to hatch naturally in spring, where they’re actually helpful insects
How to prevent surprises
- Inspect your tree before bringing it inside
- Look closely for unusual brown masses on branches
- Gently shake the tree outdoors if possible
