Monday, October 25, 2010

European Hornet

Click to enlarge

I received a call from a Bull Creek neighbor who was concerned about a wasp or bee species which appeared to be boring into her big oak tree.  She had taken several good quality pictures (see picture), allowing the identification of European Hornets, Vespa crabro.

According to Wikipedia, they are a threatened or endangered species in parts of Europe and are a protected species in Germany.
"They are not especially aggressive, especially when compared to yellowjackets, but will sting to protect themselves or their nest.  Nests can be approached without provocation (by moving slowly and not breathing towards the nest) to about 50 cm (20 in)."  Breathing into their nest had never entered my mind!
They were first encountered in the United States in 1840 in New York.  Detailed information from Penn State includes the fact that although they are Vespids similar to yellowjackets and baldfaced hornets, they are the only true hornet in the US.
They make paper nests similar to our baldfaced hornets, but rarely in the open, rather selecting cavities in trees or houses.  Their colony may contain 300-800 workers.  They sometimes damage trees and shrubs by girdling branches while collecting bark and sap.  They will also damage apples on the tree.
"Each fall, the colony produces males and females that mate, and the females become next year's queens. Only the overwintering queens survive in protected sites such as under loose bark, in tree cavities, and in wall voids of buildings. All other colony members produced in the current year will perish."
Like most introduced species, these are likely to be permanent fixtures in nature.  Since they are endangered in Germany, I am sure my neighbor would be willing to send them back to Europe if they would pay for it.  Meanwhile, if they come to live in your house, get professional help.  Plugging their hole will simply cause them to chew another one, possibly into the house itself.  And what ever you do, don't breathe into their nest!