PHILADELPHIA – At first glance, the knobby tan lump hanging from a Philadelphia man's Christmas tree looks like it could be part of the branch, but the photo actually shows a praying mantis egg sack, according to WMBF.
"If you happen to see a walnut sized/shaped egg mass on your Christmas tree, don’t fret, clip the branch and put it in your garden," Daniel Reed wrote on Facebook. "These are 100-200 preying mantis eggs!" Reed said he found two egg cases, called oothecas, on his tree this year.
Dr. Gavin J Svenson, curator of invertebrate zoology at the Cleveland Museum of Natural History, confirmed the photo and said the ootheca allows the praying mantises to survive the cold of winter until temperatures rise. Because heat signals that it's time for the insects to hatch, Svenson warned that bringing them into a warm home could accelerate the process.
Praying mantis eggs riding into homes on Christmas trees is not unheard of. A few years ago, the children in this Maryland family spent the start of the New Year collected hundreds of tiny, unexpected house guests after praying mantises hatched inside the house, according to WTOP.
For anyone who finds a similar growth on their tree this year, gardening experts with the University of Maryland Extension recommend immediately placing the egg case outside on an evergreen shrub or tree, if possible. The cases shouldn't be left on the ground or in damp places where they might rot.
Praying mantises will feast on pests in a garden, and those who find a Christmas tree egg case may want to lay off the pesticides next year.