Perhaps you've seen these little guys buzzing around lately -- and if so, you've probably taken a step back.
Hornets, right? Guess again. They're cicada killers, and they're only threatening if ... well, if you're a cicada.
According to Cincinnati Zoo & Botanical Garden head insect keeper Mandy Pritchard, the cicada killer (Sphecius speciosus) is a solitary type of burrowing wasp that's often mistaken for a hornet. She said they're most commonly found here locally hunting cicadas in trees or burrowing in soft ground.
Although the females are equipped with stingers, she said, they usually reserve that weapon for cicadas. Female cicada killers will only attack humans if they are provoked or stepped on, Pritchard said.
"It's not going to come after you to sting you," she said. "It's not interested in anything that you have, because they don't go after human food like another kind of wasp or yellow jacket might. And they don't have a nest to defend, which is what happens with other wasps when you get too close."
The males of the species do have a tendency toward aggression, she said, as they're competing for the attention of females. Once they feel they're in the perfect locale to attract the fairer sex, they tend to get territorial. Fortunately, she said, the males aren't equipped with stingers, so they're all bark and no bite.
"The males will wrestle each other for the ladies in the area to get the best spot to scope out females that might be passing by," she said. "The males would probably love to sting you, but they can't."
Perhaps that type of aggressive behavior led workers at the Campbell County Library in Cold Spring, Kentucky, to put out orange cones and caution tape around their entrance landscaping. Public relations manager Kiki Dreyer-Burke explained that after their unexpected guests arrived, they quickly called in their pest-control company, which identified the insects as Japanese hornets. Unlike cicada killers, Japanese hornets have a venomous sting that can be downright deadly.
Dreyer-Burke said that after hanging a sign warning patrons of Japanese hornets, library staff began to question the legitimacy of the information and did what librarians do best: Research.
"This is why I love working at a library," she said. "I asked the reference librarians, and by the time it crossed my desk I had pictures and facts detailing each kind. It was then we confirmed, yes, we have cicada killers and not Japanese hornets."
Identifying the species can be a bit vexing, Pritchard said, since they bear a striking resemblance to European hornets, which sport primarily yellow stripes on their abdomen as opposed to the black stripes on the cicada killers.
In addition, she explained, cicada killers dig a network of underground tunnels to house their larva instead of above-ground nests like hornets.
"You could look it up in a field guide to really tell the difference between the two, or you could just play it safe, obviously, and not mess with it," she said.
Although the insect may appear outwardly intimidating, she said, they serve an important purpose in nature by both pollinating plants and keeping the cicada population in check. She said the species preys solely on the dog-day cicadas, which arrive every year in the Tri-State from mid-summer to early fall.
"This is the time of year they emerge as adults -- and that's when the cicadas are active, so that's when they're hunting cicadas for their offspring, to paralyze them and feed them live to their young," she said.
Once cicada killers locate their prey, Pritchard said, they send them into a state of paralysis using their stingers. They then relocate the cicadas to their underground lair, where they either lay a male or female larva egg, which soon hatches and feeds on the living but anesthetized cicada.
"It just takes a couple of days for the eggs to hatch, and it just takes a couple of weeks for the larva to consume the cicada, or sometimes cicadas," she said. "The male egg only needs one cicada to make it through its life cycle, but the female egg would need two or three cicadas. She knows up front if it's male or female, so she knows how many cicadas to provide to each egg."
For those lamenting the grizzly demise of the anesthetized cicada, Pritchard said, the story doesn't necessarily end there. A parasitic type of wasp, named cow killer -- named for its incredibly painful sting -- preys on the newly hatched cicada killer larva. She said the species invades the cicada killer tunnels and lies in wait for the larva to emerge.
"The female cow killer will find the little chamber underground that the cicada killer has placed the cicada and the larva in and she will parasitize that. She will lay an egg, and when that egg hatches, it will eat the fully developed larva of the cicada killer," she said.
Noting that the 17-year cicada emergence is imminent, Pritchard said that, unfortunately, the cicada killers only prey on the dog-day or large green cicadas that emerge from the ground yearly now with their staggered development cycle. She also said it's an incredible feat for the female cicada killer to become airborne with a giant cicada in her grasp.
"There's no reason to be afraid of them," she said. "They don't affect us negatively at all. And they're fun to watch. If you've ever watched one catch a cicada, it's impressive."
Watch the Youtube video here.
After realizing they were given erroneous information at the library, Dreyer-Burke said, their first action was to change the sign from Japanese hornet to cicada killer. She said their second action was to hire a new pest-control company.
First and foremost, she wants to assure library patrons that they're aware of the unexpected guests and in the process of extraditing them.