SciTech

Giant cicada killer wasps? Not to worry

This pair of cicada killer wasps may be large and look menacing. But they hunt cicadas, are not aggressive toward humans and pose no threat to the public.
This pair of cicada killer wasps may be large and look menacing. But they hunt cicadas, are not aggressive toward humans and pose no threat to the public. naturalsciences.org

About this time each year, people across the United States encounter very large, reddish-colored wasps flying about their yards, parks, playgrounds, open fields and even woodlands. These wasps most often are seen patrolling open spaces in groups.

On occasion, they seem to collide or tackle one another in mid-air, dropping to the ground in a tussle that appears every bit as serious as a mixed martial arts bout on pay-per-view. Now look up into the trees, you might see a few of these giants inspecting the trunks and branches, going up and down and back and forth as though searching for something.

So what are these big wasps? And what are they doing?

Meet the cicada killers. As the name implies, these wasps are predators of cicadas. There are four species found in the United States, but only one occurs in North Carolina: the Eastern cicada killer, Sphecius speciosus.

Cicada killers often gather into leks – places where they congregate to breed and dig burrows to rear their young. All too often, as these insects increase in number, so do the incidents of human-wasp encounters. Most extension agents, entomologists, pest-control companies and local museums, zoos and nature centers have come to expect a flurry of phone calls and emails from people as they stumble upon these insects.

But don’t be afraid: Cicada killers are not aggressive. In fact, they might even “appear to be curious,” often flying up to and around you as though investigating your approach and intentions. Unfortunately, this behavior sends many folks into a panic. Interestingly, it’s the males who most often engage in this activity. But the males are, in fact, completely harmless: They lack stingers.

In contrast, female cicada killers are equipped with rather large stingers and venom adapted to paralyze cicadas (effective only on insects, not people).

So why would these wasps paralyze cicadas? As it turns out, each female cicada killer is a potential mother, and as nature mandates, these expectant mothers follow the call to secure and provide nourishment for their young, which in this case, happens to come in the form of cicadas. So it’s no wonder the occurrence of cicada killers coincides with the annual arrival of cicadas.

Given their inoffensive nature, when left alone they have no interest in stinging people. But should you choose to grab or handle one, be prepared to receive a sting … which when compared to most other smaller bees and wasps is surprisingly quite mild.

Please help pass on the word that these wasps are not aggressive and pose no threat to the public.

For more information: www.bugguide.net/node/view/514.

Bill Reynolds is curator of the Arthropod Zoo at the N.C. Museum of Natural Sciences.

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