Yellow jackets aren’t bees … or hornets

I know it seems like splitting hairs, at a time like this, but … those aren’t bees.

Once upon a time, a long time ago, I was running a research project investigating the ecology of salamanders in the Nantahala Mountains of western North Carolina. A group of about a dozen students from the University of Georgia were taking a summer course at the field station where I was based and had asked to see the study. Salamanders are primarily active at night, so I had outfitted the group with headlamps and, one damp evening after dinner, we headed out to the study site.

Waiting for the forest to get dark enough to begin work, I was pointing out some of the insect traps I had planted in the litter to measure the ‘manders’ prey availability.  With no moon and overcast skies, the woods went black by about nine. We switched on our lamps, took two steps, one of the students tramped on the opening to a yellow jacket nest and our work night was over.

Imagine, if you will, our mad rush down the steep slope, circles of light from our headlamps bouncing crazily about as we ran with several hundred wasps in hot pursuit.

“Turn off your lights!” I yelled. As daytime creatures, jackets don’t see well at night. “I’m allergic to bee stings!” hollered back one of the students.

Of course, yellow jackets are wasps, not bees. Like honeybees and bumblebees, their abdomens are patterned with alternating black-and-yellow stripes. But while bees are covered with hair-like structures called setae, wasps are largely hairless. Also, wasps have a thin, well-defined waist, a pointed abdomen and fold their wings like a fan when resting, while bees have a less sharply pinched in waist, a rather rounded butt and don’t fold their wings at rest.

Oh, and unlike bees, wasps have no barbs on their stingers so they can nail you multiple times, while a bee’s stinger anchors in your skin and rips from the bee’s abdomen, killing it.

It’s yellow jackets, not bees, that you’ve been waving away from the picnic table or found congregating around the Dumpster in back of your favorite restaurant. Like most other wasp or hornet species, they primarily are predators on other insects who supplement their diet with nectar from flowers or other sugary sources. But yellow jackets also are much more likely than the others to scavenge for meat and sweet beverages from your plate and mug, and it’s for this reason they are the rogues behind some 70 percent of all stings.

Although it may take a specialist to tell the difference, not all yellow jackets are the same. Of the several North American lookalikes, our two most common forms are a native species, the Eastern, and an invader from Europe, the German.

The Eastern typically builds its nests underground, while the German prefers holes in trees and wall voids — crevices and fissures in our buildings allowing them access to protected spaces such as under siding, in attics or between the inner and outer walls of your house. Yellow jacket nests are made from a mixture of wood fiber and saliva, are typically grayish in color and can house a colony of up to 3,000 individuals.

For most of the year, all members of the colony will be female (the stinger is a modified egg-laying device, the ovipositor). However, in the fall, the colony’s queen will produce a number of unfertilized eggs that become males. Newly mated females, if they can find a protected site in which to pass the winter, are the only ones to survive the cold season; the rest of the colony, including the queen, will die.

In the spring, a female starts building a new colony from scratch. Nests exposed to the environment will not be reused, although German yellow jackets occasionally have been found to reoccupy a nest in an especially well-protected location such as an attic crawl space.

The new queen (called a foundress) will construct the first few cells of the nest herself, lay a fertilized egg in each one, and then capture and crush insects and spiders to feed to the developing larvae. When the first generation of juveniles metamorphoses into adults, they’ll take over the tasks of enlarging the nest and caring for the larvae so the queen can concentrate on reproduction.

Yellow jackets occasionally will build aerial nests, completely enclosed globular colonies with a single entrance hole at the bottom that can grow to the size of a basketball over the course of a summer. These nests look a lot like those of the closely related bald-faced hornet, which is actually a wasp and not a true hornet.  But another time. …

Ken Baker is a scientist and a professor in the Department of Biological and Environmental Sciences at Heidelberg University.