Wasps carry grass… and other things

While cleaning my windows today, I removed the screens and made an unpleasant discovery. Some insect had wedged bits of material into little nests around the edges of two window screens. I brushed it off, noticing that each nest looked like brown dried grass with a bright green squishy center. Then I looked more closely at what plopped onto the ground. The bright green bits looked like baby grasshoppers. Were they grasshopper nests? (In the windows?!)

Then a wasp flew up… carrying one of the bright green grasshopper like things, which was a bit larger than it was! It flew to where the screen had been and kept bumping along the window frame looking for the nesting site (presumably). Was it food? What? This is exactly what it looked like:

Some googling brought me to this description of the grass-carrying wasp, an insect I’d never heard of. Apparently they bite off bits of grass to wedge them in “cavities.” They then hunt for tree crickets. When they find a cricket, they sting it, paralyze it, and carry it off to sequester in a grass-lined nest, then lay an egg on it. When the egg hatches, the larva can immediately start eating the cricket. I was nauseated by the description, yet simultaneously felt bad at having cleaned out all the nests, after reading the very sympathetic description of this “beneficial wasp” at the above link. (Apparently ridding the trees of crickets that feast on them is good, and the wasps are also pollinators and not aggressive.)

Still, I don’t really want them in my windows! And I think my forest offers many other hollow woody crevices for the wasps to populate. To me the most salient part of their behavior is the cricket-hunting, paralysis, and egg-laying, but I guess the grass nesting is kind of interesting too (it’s not just for the birds!). I hope they enjoy feasting on the local tree crickets!