Friday, September 29, 2006
Grass-carrier wasp, or the wasp that clogs storm-window tracks
For the past several years, when I try to remove my triple-track storm windows for a rare washing, I find the tracks clogged with packed grass nests. Sometimes these wads of grass have nearly colorless crickets in them and some kind of cocoon. I have also found wasp bodies trapped between the windows, and now I have finally linked these all together.
The culprit of this nest-building is a Grass-carrier Wasp of the genus Isodontia, probably species philadelphica (there are a number of Isodontia species in the eastern U.S.). This wasp gathers pieces of grass often longer than its one-inch body and tucks these pieces firmly into some crevice — into grooves of bark, old hives and commonly into window tracks.
A solitary wasp
The Grass-carrier Wasps are "solitary wasps" and do not have workers to help build nests and raise larvae. They are usually not aggressive in protecting their nests and sting only when harassed or handled.
The Grass-carrier Wasp belongs to the family of digger wasps, the Sphecidae. These are known as thread-waisted, have shiny black bodies and smoky wings. Unlike the spectacular ichneumon wasps written about recently in this column [Mosquito, August 4, 2006], these wasps are small, ant-like creatures. The cocoons are elongated and a yellow-cream color. Inside, the larvae are grub-like with no legs.
A minor nuisance
As I have read up on this wasp I find that many people have enjoyed watching wasps as they carry out their wide variety of interesting behaviors — building spectacular nests, killing large insects and carrying them around and observing how through the years they can move from building nests in hollow twigs to using our window tracks. Howard Ensign Evans, a former head of Harvard's Museum of Comparative Zoology (MCZ), wrote a delightful book on his observations, The Wasp Farm.
Another local expert on birds and insects, videographer Dick Walton, has recorded wasps, and you can watch some of these fascinating creatures in action online at www.nhsvideo.com/wasps.html.
References: The Wasp Farm by Howard Ensign Evans,http://bug-guide.net;www.ipm.iastate.edu; www.uky.edu/ag/critterfiles.
© 2006 The Carlisle Mosquito