Wildlife Watching Wednesday: The Long-Tailed Giant Ichneumon Wasp

By: Tom Berg

Most people don’t like wasps, and for good reason – they can sting you!  But not all wasps can sting, and even though the long-tailed giant ichneumon wasp looks pretty scary and intimidating, it is totally harmless to humans.  These wasps are not aggressive and they cannot sting you.

Females of this species have a very long “tail” that is actually an ovipositor (males do not have one), even though some people might see it and think it is a long stinger.  After mating with a male, the female wasp uses its ovipositor for the sole purpose of depositing eggs into the burrows of other insects in dead trees or other pieces of wood.

The long-tailed giant ichneumon wasp is usually brown or reddish brown in color, with vivid black and yellow stripes.  Adult females can easily reach two inches in length, and when their long ovipositor is extended their overall length can be five inches long or more!  Its wings are long and narrow, just like the wings of many other wasp species, but it is still a strong flier.

As mentioned above, female wasps of this species search for fresh holes bored in dead wood where they can lay their eggs.  They are very particular about where they deposit their eggs, too.  They look for a hole that contains the larva of a specific wood wasp, also called a horntail (a wood-eating sawfly).  They paralyze the horntail larva host and lay their egg on it so their offspring can consume it and then pupate over the winter.  They will emerge from the wood the following spring or summer as an adult.

The long-tailed giant ichneumon wasp is very common and can be found throughout the Midwest and the entire eastern half of the United States.  Most people have never seen one, simply because this insect typically does not cross paths with humans.  It’s just another great example of the incredible species diversity in our great outdoors, whether we know about it or not.

This photo of the long-tailed giant ichneumon wasp was taken by Mark Berg.

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