Figure 1. Cicada killer wasp. Credit: A. Bachmann
Cicada Killer Wasps
Over the past couple of weeks, we have received reports of large, menacing wasps appearing in residential yards and gardens. The wasps in question are commonly referred to as cicada killers (Sphecius speciosus). These wasps become active at approximately the same time as cicadas, which are used as a food source for the larvae of cicada killer wasps. In South Dakota, these wasps are now active and attracting a lot of attention due to their large size and somewhat terrifying appearance.
The adult wasps range in size from 1.5 to 2 inches in length. Cicada killer adults will have a reddish-brown thorax (area directly behind the head) and black abdomen with yellow banded markings (Figure 1). These wasps are often observed hovering close to the ground near mounds of excavated soil. The mounds are created when the female cicada killer wasps dig tunnels in areas of bare, sandy soil to create nesting habitat. These wasps are often seen in groups near garages, patios, sidewalks, retaining walls, and in playgrounds where dry, bare soil is readily available.
Cicada killers are solitary wasps, which means one female will dig and provision her eggs alone (Figure 2). However, there are often multiple wasps using the same general area of suitable habitat in a yard. The female cicada killers hunt cicadas or other large insects near their selected nesting site. Once prey is caught, the wasp paralyzes it using her stinger and carries it back to her nest. She will then lay an egg on the prey and burry it. When the egg hatches, the larva will consume the prey, spin a cocoon, and overwinter in the soil. Warranting suitable environmental conditions, new adult cicada killer wasps will emerge from the area during the following year.
Figure 2. Cicada killer wasp digging a hole in a lawn. Credit: A. Varenhorst
No Need to Manage
We receive many questions regarding the management of cicada killer wasps. For the most part, these questions arise because of their size and habit of nesting close to areas of human activity. Although they do cause minor disturbances in lawns and gardens, these wasps are benign. Cicada killer wasps may look deadly, but in reality, they are rarely aggressive towards humans or pets. Male cicada killers can be territorial. They are sometimes observed patrolling an area and may buzz around passing people or pets. Male cicada killers may appear threatening, but they lack a stinger and are thus incapable of inflicting a painful sting.
If cicada killers are nesting in an undesirable location, the long-term solution is to amend the habitat in that area. As long as an area remains bare, with loose or sandy soil, it has an increased chance of being utilized by subsequent generations of cicada killer wasps.
Figure 3. Cicada killer nest located in dry grass near a driveway.
Credit: A. Varenhorst