Mistaken Identity: Is that a murder hornet? Wasps in Southern Arizona

Washington State Department of Agriculture entomologist Chris Looney displays a dead Asian...
Washington State Department of Agriculture entomologist Chris Looney displays a dead Asian giant hornet, a sample sent from Japan and brought in for research, on May 7, 2020, in Blaine, Washington. - The new Asian hornets that have been found in Washington state may be murder on already stressed-out honeybees, but for humans its like a repeat of the sensationalized scare that turned Africanized killer honeybees of the 1970s: a real and nasty bug hyped into a horror movie motif that didnt quite fulfill its scary billing. Numerous bee and insect experts tell people to calm down about the so-called murder hornets, unless you are a beekeeper. (Photo by Elaine Thompson / POOL / AFP) (Photo by ELAINE THOMPSON/POOL/AFP via Getty Images)(ELAINE THOMPSON | POOL/AFP via Getty Images)
Published: Sep. 23, 2020 at 3:33 PM MST
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TUCSON, Ariz. (KOLD News 13) - There seems to be some confusion in Southern Arizona, with some thinking what they are seeing in their backyard may be more serious.

Here’s an example of one voicemail left for entomologists at the University of Arizona College of Agriculture and Life Sciences:

“My family and I were out by the pool and we saw a murder hornet... It was definitely at least two inches and really big and scary.”

Messages, photos and species identification requests have flooded the college since May, with many Arizona residents reporting potential sightings of the now infamous Asian giant hornet, or “murder hornet.”

“Sure enough this year, we were just inundated with inquiries. People thinking they have the Asian giant hornet or the murder hornets in their yards or around their house, or whatever," said Gene Hall. Hall manages the University of Arizona Insect Collection.

“Right now, they are currently restricted the pacific northwest," said Hall. "Though, it hasn’t even been confirmed yet if they’ve been well established in that area.”

The reality is a case of mistaken identity for some of Arizona’s native wasps, including the cicada killer and tarantula hawk. Hall said the nicknames sound scary, but the wasps are not after you.

“In 36 years that I’ve been studying and working on insects in the Sonoran Desert, I’ve never known anyone to be stung by one of these wasps. If anybody has been stung, no doubt it’s because of defense mechanism," said Hall.

Here are some answers to common questions and guidance from UArizona entomologists:

Q: Cicada killers are not small and have been commonly mistaken for the Asian giant hornet. How can we tell them apart?

A: There are a few characteristics that work for immediately separating these two groups of wasps from each other. The head of the Asian giant hornet is larger or broader than that of the cicada killer wasp. The thorax, or middle section of body behind the head, is black in the Asian giant hornet and reddish-brown in the cicada killer wasp. For the abdomen, or the third body segment, the Asian giant hornet has solid dark bands and no spotting, while the cicada killer wasp has bands wider towards the middle and spots on some abdominal segments.

Q: How do cicada killers support our local ecosystems?

A: As with all species, cicada killer wasps are tied to other organisms as part of the great biodiversity of our region. Though they prey on cicadas as food for their larvae, this is part of the checks and balances of nature — two organisms that have co-evolved with each other. Undoubtedly, the cicada killer provides a high-protein meal for other organisms, including mammals and birds. Cicada killers do well in the Arizona desert since they prefer to burrow in dry soil that forms the larval chambers.

Q: What should folks do if they spot one?

A: Leave it alone. These gentle giants of the wasp world have no interest in humans; they are too busy living their lives and searching for cicadas to provide a meal for their offspring. During my 36 years studying insects of the Sonoran Desert, I’ve not known anybody to be stung by these wasps, plus it only would happen as a defensive mechanism.

Q: Now, tarantula hawks. What are these wasps most known for?

A: These wasps are known primarily for their interactions with tarantulas, thus the common name tarantula hawk wasp. In the same manner as the cicada killer wasp does with cicadas, the tarantula hawk wasp uses tarantulas as a food source for their developing larvae, or grubs, in underground chambers. The tarantula is paralyzed by the wasp’s sting, immobilizing it while the tarantula hawk grub feeds on the large spider until ready to pupate, then emerging as an adult wasp. As with the cicada killer wasp and cicadas, the tarantula hawks and tarantulas are connected to each other in the natural cycle of life and death.

Q: What are their most distinguishing characteristics?

A: The tarantula hawk is large and very conspicuous compared to most other wasps, the body being black and the wings red, orange or dark bluish-brown. Their body and wing color are completely different than that of cicada killer, so it’s easy to separate the two groups of wasps from each other. I’ve only had a few inquiries confusing tarantula hawks with the Asian giant hornets, but that was mainly due to size of these wasps, as neither looks similar to the other.

The adult tarantula hawk will visit flowering plants, feeding on the floral nectar. They are generally non-aggressive; I’ve not known anybody stung by these wasps unless it was defending itself. Tarantula hawks are pollinators, and on the University of Arizona campus you can see them visiting milkweed flowers on the south side of the Chemistry Building, plus other plants on campus.

Q: These bugs pack a serious sting. How do we avoid getting stung?

A: As with all stinging insects, leave it alone. Why aggravate them? Stinging insects will generally only do so while defending themselves, a nest, their offspring or territory. If you have concerns, best thing to do is give it space and go your own way. Otherwise, enjoy the beauty of these beasts as they’re a part of the amazing biodiversity inhabiting the Sonoran Desert. If possible, take time observing them in their natural habitat, learning something new about an animal you may not have noticed before. You’ll see there is really nothing to fear, and in the end gain a deeper appreciation for the natural world that surrounds us.

“They are just part of the national, beautiful biodiversity we have here in the southwest and Sonoran Desert and just leave them alone, let them do their thing," said Hall.

While the Asian giant hornet has not been found in Arizona, if residents see large wasps and are unsure, they can contact the UArizona Insect Diagnostics Clinic for identifications.

For more information on cicada killer wasps, click here.

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