Several emails have come to the help desk this week reporting “swarms of wasps” in clients’ yards, “flying quite low to the ground.” One Fulton County resident said, “they seem to be in constant motion, never landing or stopping. Their flight pattern gives the impression that they are actively searching for something.”
Well, they were right! The mysterious swarming wasps in question are blue-winged wasps, also called digger wasps or Scolia dubia. Blue-winged wasps are about ½-1 inch long and cloaked in black from the tips of their antennae to the top third of their abdomen. They give the impression of a film noir character wearing a black leather trench coat. The rest of the abdomen is a rusty, reddish brown, with two bright yellow spots. Their powerful wings are a deep navy blue with an iridescent sheen in the sunlight.
Blue-winged wasps are what we call “solitary wasps”—they live independently of one another and build their nests and feed their offspring alone. This is unlike paper wasps and bald-faced hornets, which are social wasps, living in one large colony where groups of wasps have designated jobs. Because the whole colony lives in one place, social wasps can be more aggressive and will defend their family unit at all costs. On the other hand, solitary wasps, like the blue-winged wasp and many others, are not aggressive. Because they’re on their own, they can’t risk stinging you and getting squashed, as no one else will step in to feed their offspring. Solitary wasps have a two-track mind: survive and reproduce.
Many solitary wasps specialize on a certain type of prey, and the blue-winged wasp is no exception. Scolia dubia are predators of June bugs and Japanese beetles. The female wasp digs to find the larval form of the beetles, also known as “white grubs,” stings the grub to paralyze it, then lays her egg on the grub’s body. Once the wasp egg hatches into a larva, the larva feeds on the paralyzed grub as it develops. The wasp larva eventually pupates in the Fall, rests in its pupa throughout the winter, then molts into an adult in the Spring. Thus, the cycle continues.
You might be saying to yourself, “Hey, Japanese beetles destroy my flowers every year!” or “White grubs are the bane of my bermudagrass lawn!” If you’re in this camp, you will be happy to see blue-winged wasps in your landscape. These insect predators help keep beetle populations low and are considered our allies in the garden. They begin foraging for beetles once the beetle populations have begun to build up, generally around August in North-Central Georgia.
Blue-winged wasps are also great pollinators of garden plants and native flora! Searching and digging for grubs is no easy feat, so wasps visit flowers for a quick “snack” of pollen and nectar, which are high in protein and carbs, respectively. Visiting flowers gives them the energy they need to continue their search for prey, and they unwittingly pollinate our plants in the process. According to Penn State University Extension, they are especially fond of goldenrod!
So don’t fret if you see these insect allies patrolling the ground in your yard. These gentle wasps are helping keep Japanese beetle and June bug populations under control and pollinating our native plants in the process.
Thank you to our Fulton County clients who reached out about these beautiful wasps. Luckily, these clients sent great photos I could use to make an identification. If you’ve seen an interesting or strange insect in your yard, send it over to me at gabrielle.latora@uga.edu or any of our Agriculture and Natural Resources team.
Further reading
Blue-winged wasp factsheet (NC State Extension)
Blue Winged Wasp, Scolia dubia—is a Real Asset! (Penn State University Extension)
Blue-winged wasp profile (Illinois Department of Natural Resources)
Garden Wasps – Where is the Love? (UGA Center for Urban Agriculture)
Gabrielle LaTora is one of UGA Extension Fulton County’s ANR agents. An entomologist by training, Gabrielle is interested in insects on farms and in gardens and is passionate about closing the gap between people and their food. Gabrielle helps coordinate Fulton’s Master Gardener Extension Volunteer program, oversees the North Fulton Community Garden, answers clients’ questions about gardening and natural resources, works with urban farmers, and delivers high-quality educational programs for Fulton County residents.
