Larry Wegmann emailed me this picture of a large wasp-like insect he photographed in his garden. Here is his description.
"This guy has found it's home among our impatiens in our backyard. It protects this patch from other intruding wasps. I noticed in these pictures that this is probably a male wasp. If its
his girlfriend he is chasing away from his nectar source, he needs a
lesson in vinegar vs. honey. By the way I took these with my Nikon D90
with a 300 mm + 1.4 tele-extender = 420 mm lens. I wish this guy would tolerate me getting close with the Pentax with high speed video. He is very alert to my presence."
Larry had already identified it as a cicada killer,
Sphecius specious. The largest wasp in North America, it is fearsome in appearance but in reality it is more of a pussy cat. They emerge from the overwinter cocoons in mid-July. The female, twice the size of the male, uses her stinger to paralyze cicada and won't sting humans in self defense unless roughly handled.
Following fertilization, the female cruises around, finding a suitable site to lay her eggs, then digs a burrow with one or more side chambers. Next she patrols nearby trees until she find a cicada. Once it is paralyzed, she struggles with the flight to carry it back to the burrow. As the cicada will weigh twice her body weight, she may need a few rest stops along the way. Once she has worked it into the chamber she lays her egg on it and closes the cell with dirt. If it is a female egg, the cell usually will be provisioned with two cicadas as the larger female will require more resources to grow.
The egg will hatch in a few days and the larva will develop over 20 days and overwinter as a pupa in a cocoon. The adults, their job complete, will die off over the fall, none surviving by the next year. Meanwhile the larva is vulnerable to the same risk as its paralyzed cicada host. Velvet ants, a.k.a. cow killers,
Dasymutilla occidentalis, are actually furry flightless wasps. They specialize in solitary ground nesting bumblebees and wasps. finding their nests and laying their eggs on the cicada killer larva for their own larva to feed upon. From the cicada's point of view, this must seem like poetic justice.
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| Cicada Killer- Shelly Cox at MOBugs |
Meanwhile the
male cicada killer patrols looking for nectar and more females. It will select a territory and defend it, flying up to inspect anything that comes near and fighting off other males. Smaller than the female, they still are frightening but a hollow threat as they lack stingers. The males are more likely to buzz us humans to be sure we aren't available females. Larry's description above suggests his was a male.
Like all other animals, the cicada killer is a mixed blessing. They are welcomed by our trees as they reduce the numbers of cicadas, a forest parasite. The annual cicada likely don't see it that way. They don't have any effect on 13 and 17 year cicadas which emerge in May and June, dying off before the cicada killers arrive. With our neatly mowed lawns and loose flower beds providing both nectar and easy digging, it is no wonder that
S. specious has learned to love the suburbs. Keep your eyes open and you too may be able to follow this gift of nature.
Dick Walton's Natural History Services page has a great 4 minute video of cicada killers.
Extensive information on S. specious is available at Professor Chuck Holiday's page at Layfette College
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