Cicada Killers

Posted by & filed under Director Blog, Horticulture News.

Have you seen any flying insects lately that look like giant yellow jackets?  If you have, they are most likely the eastern cicada killer, Sphecius speciosus.  Actually it is considered a beneficial insect because it helps to regulate cicada populations. This wasp gets its common name from the fact that it hunts cicadas, which becomes the food source for young cicada killers.

Cicada killers are solitary wasps, with the female digging a 6 to 10-inch burrow (½ inch in diameter) in the ground. These diggings are usually seen in sandy or loose soil. A pile of soil or sand, depending on the soil type, typically surrounds the entrance. The female locates and stings a large insect such as a cicada or katydid and paralyzes it.  She then brings the insect back to the burrow. This can be quite an operation because the size of the cicada.  The cicada killer generally launches from a branch holding on tightly to the cicada and essentially does a powered glide towards its burrow.  It may have to drag it the final distance to her burrow.  Once in the burrow she places her prey into a chamber and lays an egg on the surface of the paralyzed insect.  The female cicada killer eventually covers the burrow, digs another, and repeats the process. The egg hatches into a grub-like, legless larva that consumes the paralyzed insect. Full-grown larvae overwinter in the burrow, pupate in the spring, and emerge as an adult during the summer—usually July and August.

Cicada killers can be up to 2 inches long and black to red in color, with yellow-banded markings on the abdomen. The head and transparent wings are reddish brown. They are not dangerous, but they are intimidating.  Male cicada killers establish territories and patrol for intruders. A male cicada killer wards off other males that enter his territory.  Anyone else, such as a human, walking into the territory is typically confronted by a very large wasp, which hovers in front of the face and zips to the side and back. However, after determining that the intruder is not a rival, the male cicada killer ignores the individual. Cicada killers are unlikely to sting a person. Wasp and bee stingers are modified egg-laying devices (ovipositors), so males are unable to sting.Females may sting if crushed, either by being stepped on with bare feet or grabbed with bare hands.

Cicada killers are more common in areas with bare soil.  Areas that are mulched, covered with grass or ground covers are much less likely to harbor cicada killers.  Sandboxes should be covered with a tarp when not in use and sand below swings, jungle gyms, or other playground equipment should be replaced with bark mulch or shredded tires.

They are fascinating insects and if you have the opportunity to carefully observe one it may well be worth the time to interrupt your busy day-to-day activities and watch nature in action.