Cicada killers (Sphecius speciosus) are large, solitary wasps that are active from June until September. There are actually four different species of cicada killers in North America, and this species is more appropriately called the eastern cicada killer. However, since it is the only species found in most of the eastern U.S., the “eastern” portion of its name is usually left off of its name. Cicada killers are among our largest wasps. They can range between 0.6 and 2 inches long. The females are larger than the males.
Male cicada killers emerge from their underground burrows before the females emerge. Each male will try to establish a territory in the general vicinity of where it emerged. If multiple males emerge in the same area, then they may fight for the territory. Fights consist of in-air wrestling matches where each male tries to get on the back of the other male. The fights will continue until one of the males gives up and flies off.
If anything enters a male’s territory, it will quickly fly up to see if the “intruder” is a female cicada killer. It can be quite intimidating when such a large wasp flies up to you, but male cicada killers lack a stinger so there is nothing they can do except check you out. If a female cicada killer enters a male’s territory, then they may mate; however he may first have to fight other nearby males who also want to mate with her. After mating, the female flies off to find a suitable area to dig a nesting tunnel.
Cicada killers prefer to dig nesting tunnels in areas with dry, loose soil and little vegetation. The female uses her jaws and front legs to loosen the dirt and pushes it out with specialized spikes on her back legs. She may also turn around and push mounds of dirt out with her head and front legs. Her nesting tunnel can be several feet long and have multiple egg chambers branching off the main tunnel. The soil removed from the tunnel and egg chambers is often piled around the entrance and is can be one of the most obvious ways to locate a cicada killer nesting tunnel.
After creating an egg chamber, the female cicada killer will go hunting for cicadas. She appears to hunt primarily by sight and will often attack cicadas in flight. When she attacks a cicada, she grabs and stings it. The venom she injects into the cicada paralyzes the insect, but does not kill it. She then carries the cicada back to her burrow.
The cicada she captures can weigh up to twice as much as the cicada killer. If she captures the cicada close to the ground, she may drag it all the way to her nest if the nest is close or she may drag the cicada up a tree before taking flight with it so she doesn’t have to lift it off the ground. Once back at her nesting tunnel, the female cicada killer will drag the paralyzed cicada into the tunnel and into the awaiting egg chamber.
Female cicada killers choose the sex of their offspring by deciding whether or not to fertilize each egg that they lay. Fertilized eggs will develop into females, while unfertilized eggs will develop into males. If she is going to lay an unfertilized egg, then she will only put one cicada into the egg chamber before laying an egg on the cicada and sealing the chamber. However, if the egg will develop into a female cicada killer, then two or three cicadas will be put in the egg chamber before the egg is laid. The female eggs are given more food because they will develop into larger adults.
The eggs will hatch a few days after they are laid. The larva that emerges will feed on the paralyzed cicada(s) that are in the egg chamber with it. After a week and a half to two weeks, the larva will have consumed all of the food in its chamber leaving nothing but the cicada’s exoskeleton. The larva will then spin a cocoon and hibernate until the following spring when it will pupate before emerging as an adult in the summer. No adult cicada killers live through the winter.
If you have cicada killers in your yard, often the best course of action is to simply ignore them or make the area unattractive to them. Spraying cicada killers does little long-term good because the adults will die in the fall anyway and the area will likely attract new cicada killers next year. To make the area unattractive to cicada killers, try to keep the area moist because cicada killers don’t like wet ground. Also, try to grow more vegetation in the area because they rarely use heavily vegetated areas.
Although cicada killers can be intimidating because of their large size, they pose relatively little threat to most people. Male cicada killers don’t have a stinger and therefore are incapable of stinging. While female cicada killers can sting a person, they rarely do so. They are too busy digging nesting tunnels, capturing cicadas, and laying eggs to defend their nesting sites. Typically, you have to step on them, try to squash them, or do something similar that directly threatens their lives to get stung by a cicada killer. In the end, they are really a very interesting creature that plays a valuable role in the ecosystem by helping to control cicada populations and as potential prey for many of our insectivorous birds.
This article was part of Shannon’s original Kentucky Pollinators and Backyard Wildlife blog which evolved into the blog for Backyard Ecology. All of Shannon’s Kentucky Pollinators and Backyard Wildlife blogs can be found at https://shannontrimboli.com/posts/blog/.
Backyard Ecology: Creating Space for Pollinators and Wildlife
Nature isn’t just “out there.” It’s all around us, including right outside our doors. Hi, my name is Shannon Trimboli, and I am the host of Backyard Ecology. I live in southcentral Kentucky and am a wildlife biologist, educator, author, and owner of a nursery specializing in plants for pollinators and wildlife conservation. I started Backyard Ecology as a way to share my love of exploring nature and learning about different plants and animals. I invite you to join me as we ignite our curiosity and natural wonder, explore our yards and communities, and improve our local pollinator and wildlife habitat. Learn more or subscribe to my email list at www.backyardecology.net.