I decided to devote this week’s contribution to a single unpopular species. Known for its large size, aggressive behavior and powerful sting, the bald faced hornet (Dolichovespula maculata) is liked by few people. They’re neither completely bald faced nor technically hornets. Their white faces are sparsely covered with setae (hairs) and they are, in fact, the largest member of the yellow jacket clade of wasps.
When I spotted one building a slender, gray stalactite from the ridge of my greenhouse, I knew it was preparing to build a nest. Instead of reaching for the wasp killer, I reached for a camera. I really wanted to find where she was gnawing the wood she ground into a pulp to build her nest. I was going to stain some paper with food coloring and try to get her to build a multi colored hive. Sadly, I never found the source of her building materials.
Over the next few days I visited often. Whenever I got too close, she let me know by facing me, putting her wings back in a “V” shape and vibrating them loudly. To quote an immigrant friend, “I love this country, even the snakes warn you.” Not only does she sport black and (well almost) yellow aposematic coloration (conspicuous coloration or markings of an animal serving to warn off predators), but also what I’ve termed “aposematic sonification.” Like a rattlesnake, she makes warning sounds.

They do have their good points. First and foremost, as good mothers, they are voracious hunters of other insects, including yellow jackets, which they chew up and feed to their young. A hornet or paper wasp nest near your garden can provide both a lot of pest protection and pollination services, as the adult workers feed largely on nectar.
She laid eggs in the first four cells she had built and then one day never returned. I suspect a bird probably got her. The eggs will never hatch and the nest will forever be unfinished.
If one starts to build her nest nearby and you spot it before the first generation of workers hatches, watch for her to leave to gather wood or feed herself, and knock it down. Then leave for a while. Most likely she will get the message and move on.
This article appears in Summer of Fun! 2019.




Nice.
One of our family’s camping traditions was to set-out a scrap of meat to attract yellow jackets…and soon…the bald-faced wasp would appear, (we called it a “Wolf-Wasp” because it would grab the yellow jacket from mid-air, bite off its head and fly away.
Both species love the previous year’s Jerusalem Artichoke stalks to make pulp for their nests. They grow like weeds in our coastal climate.
Thanks for the dye idea.
We’ll give it a go.
After learning that these insects eat horseflies and deerflies, I’m in love with ’em! I just read your post and love the term “aposematic sonification”! If it isn’t a science term, it should be! Well done. Thanks!