Exploring the Ozarks Outdoors: freshare.net

The Cicada Killer Wasp

By Robert J. Korpella

First posted on 08-10-2012

A brightly colored wasp about two inches long with a menacing stinger is enough to make many people head back indoors. But cicada killer wasps are paired with mild manners to go along with their threatening appearance. At least they are docile where humans are concerned. It’s a different story for those buzzing cicadas.

Female cicada killers are armed with a stinger, and it can be substantial at nearly a quarter-inch long. They use it to inject paralyzing venom into a cicada, which eventually becomes the food supply for the next generation of these wasps. Nature is sometimes not very pretty, but it is always interesting.

imageThe females are not aggressive, and only sting when they are roughly handled or if they are stepped on. They don’t even have the tendency to protect their nests as their cousins, the honey bees and hornets do.

Males cicada killers, on the other hand, are territorial and spend the bulk of their short lives patrolling a chosen nesting site. They’ll challenge anyone and anything that enters their space—dog walkers, lawn mowers, people wielding weed whackers. Luckily, males are not equipped with a stinger.

Cicada killers dig themselves out of subterranean chambers in July. Females spend their first couple of weeks above ground scouting for just the right place to build a nesting tunnel. These tunnels are long and elaborate, reaching anywhere from 30 to 70 inches and cut about 12 to 15 inches below the surface. The female does the digging, and it’s a fascinating procedure to witness.

She prefers a southeast-facing locale in full sunlight and with well-drained, lightly-textured soils that make digging a little easier. Who could blame her? She will move about 100 cubic inches of soil during construction—enough to fill a child’s toy pail. The entrance hole has a telltale U-shaped collar of soil that the female wasp extracted.

Nests may be built under sidewalks and driveways, in gardens, in golf course sand traps, or along a patio border. The first chamber is about a foot from the tunnel’s entrance. Each nesting site has an average of 15 egg-shaped chambers, and the adult wasp supplies each chamber with one to three cicadas. The female then lays an egg on top of each paralyzed cicada before sealing the chamber’s entrance.

Eggs hatch in two to three days. The developing larva devours its cicada host in around 10 days, leaving only the hard exoskeleton behind.

By autumn, the larvae spin a silken case that hardens into a cocoon, and they will winter nestled deep inside their protective chamber. The following summer, about 40 percent of the larvae survive and emerge to start the cycle over again.

The entire process from emergence as an adult cicada killer to the insect’s death only takes about two to six weeks. Males live the shortest amount of time, a life filled with endless patrols, occasional fighting, scouting for females, and mating.

Look for cicada killer wasp nesting sites with mounds of extracted soil that look at first like a mole burrow. You may find them struggling as they carry a live, but lifeless cicada to the nest. Or, a first encounter might be a male defending his territory with a wandering flight, inches above the ground.

But the period for viewing is nearing an end. Cicada killer wasps don’t have much time. Of course, the next generation will follow the same pattern next summer.

Watch a female cicada killer wasp begin construction of her nesting site:


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