Texas A&M Entomology Research Network

Interesting Arthropods

It’s big, but it’s not a ‘murder hornet’

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Texas A&M AgriLife experts say Texans mistakenly identifying cicada killer wasps as Asian giant hornets

by Kay Ledbetter, Texas A&M AgriLife Marketing and Communications

Many insects are being mistaken for the Asian giant hornet.
Many insects are being mistaken for the Asian giant hornet.

Since the release of information about Asian giant hornets, Texas A&M AgriLife entomologists are being inundated with cicada killers and other lookalike insects submitted for identification as a possible “murder hornet,” which thus far has only been found in Washington state in the U.S.

While the agency wants to continue to encourage Texans to be vigilant in watching for the Asian giant hornet, they also want to help provide guidance that will help narrow the focus.

David Ragsdale, Ph.D., chief scientific officer and associate director of Texas A&M AgriLife Research, and professor in the Department of Entomology, said many photos of Texas native cicada killers, or ground hornets, are being submitted as suspected Asian giant hornets. He said their website receives five to 10 photos a day, and agency pest management agents and specialists around the state have also been handling inquiries.

It’s a bird, it’s a plane … it’s a cicada killer

In May, the concern about Asian giant hornet was enough to prompt Gov. Greg Abbott to request a task force be mobilized to prepare Texas against the Asian giant hornet’s arrival.

A cicada killer wasp and burrow. These are being confused for Asian giant hornets. (Texas A&M AgriLife photo by Dr. Pat Porter)
A cicada killer wasp and burrow. These are being confused for Asian giant hornets. (Texas A&M AgriLife photo by Dr. Pat Porter)

But June is the normal month for the cicada killer wasp, a common large wasp in Texas, to start showing up and this prompted posts on Facebook and in news feeds mistakenly reporting cicada killer wasps as sightings of the Asian giant hornet.

“Most everyone has seen the cicada killer wasp that is very large, but has mostly been ignored in the past,” Ragsdale said. “With the most recent news of the Asian giant hornet, they are now paying attention to the native Texas insect.”

While some people thought they had been seeing the newly pictured murder hornets for years, AgriLife Extension experts want to clarify, “No, you haven’t.” Now they are providing outlets to help tell the difference between the Asian giant hornet and similar looking pests.

Holly Davis, Ph.D., Texas A&M AgriLife Extension Service entomologist in Weslaco, and Pat Porter, Ph.D., AgriLife Extension entomologist in Lubbock, recently developed a short video explaining the differences between the “murder hornet” and several common lookalikes here in Texas.

“To date, we have identified hundreds of insects that people in Texas suspect might be Asian giant hornets (murder hornets),” Porter said. “Eighty percent of these have been either the eastern cicada killer or western cicada killer. It is understandable how non-entomologists would have trouble deciding which was which.”

Comparison between Asian Giant Hornet and look-alike wasps

How to tell the difference

“First, the Asian giant hornet is native to Japan and South Korea, and it has only been found in parts of British Columbia, Canada and the northwestern corner of Washington state,” Davis said. “There have been no confirmed reports of these hornets in other U.S. locations, including Texas.”

There are a number of Texas native species of wasp, hornet, yellow jacket and bees, but what really separates Asian giant hornet and a few of our native species is their size. The ones most likely to be confused with Asian giant hornet are three species of cicada killers and the pigeon horntail.

The Asian giant hornet is the world’s largest known hornet measuring 1.5-2 inches in length. It has a head as wide as its shoulders, where the wings and legs are located, or wider, and it is a bright orange or yellow. The thorax, or shoulder portion where the wings and legs are connected, is a dark brown, as are the antenna. It has a much smaller or pinched waist and then smooth looking brown and orange stripes cover the abdomen.

The cicada killers, of which there are three different species here in Texas, are also quite large, measuring 1-1.5 inches in length. But they will all typically have a head that is narrower than the thorax. The head and the thorax are typically the same color, a darker orange or brown color. It does also have a pinched waist. But the stripes on the abdomen will be jagged and sometimes look like mountains.

The eastern cicada killer tends to be black and yellow. The western cicada killer is closer in color to the Asian giant hornet, being reddish brown and yellow. But there is no contrasting color between the head and thorax and the stripes are jagged on the western cicada killer.

The other group of insects that are most commonly confused with the Asian giant hornet are the horntail or wood wasps. They are large, have a distinct head that is as wide or wider than the thorax, and may share the same coloration as the Asian giant hornet. However, there is one trait that is easy to spot that is different, and that is the waist. Horntails lack any appearance of a waist.

Harmful or just alarming

The Asian giant hornet preys on bees and can decimate local honey bee populations, essential for most fruit and vegetable crop production. The Asian giant hornets also are fiercely protective of their nests and will deploy painful stings that can cause fatal allergic reactions in people already sensitive to bee stings.

The cicada killer and wood wasps, however, are solitary and thus do not aggressively protect their nesting sites by attacking in large numbers, Davis said. Cicada killers, however, may cause alarm due to the males’ territorial behavior, dive-bombing or buzzing people and animals that walk into their territory.

“Although cicada killers are solitary, you can often find numerous individuals in areas with sandy soils where females dig nests in the ground,” she said. “These nests appear as dime to quarter sized holes.  As females come and go, provisioning their nest with cicadas they paralyze with a sting and carry back to their nests.

“The males are more interested in mating. Thus, they may try to chase off intruders they perceive as a threat to their mating opportunities. However, male wasps are not capable of stinging, thus they are not dangerous, just a nuisance for a few weeks out of the year during the nesting season. Females can sting but are not aggressive and reports of stings are rare.”

Horntails and wood wasps may have what appear to be very long stingers, but they are unable to sting.  They lack venom glands and instead they use this structure, called an ovipositor, to insert eggs into plant tissue, hence the name wood wasp, Davis said.

Some ‘spooky’ arthropods call Texas home

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Excerpted from an AgriLife Today story by Paul Schattenberg, Texas A&M AgriLife Communications

The state of Texas is host to some interesting arthropods that are some of the most iconic symbols of Halloween. Our entomologists give some interesting facts about a few of these residents that make the Lone Star State their home.

Tarantulas — More hairy than scary

Tarantula on hand
Tarantulas are actually very docile. (Texas A&M AgriLife Extension Service photo)

Extension entomologist and long-time tarantula enthusiast Molly Keck said while tarantulas are large and eerie looking, they are actually very docile and rarely bite.

“The exceptions are when they paralyze their prey to eat it — or they may bite if threatened,” she said. “But though their venom can paralyze an insect or very small animal, it rarely causes a severe reaction in humans.”

Keck said when in danger some species of tarantula can rapidly dislodge prickly hairs from the top of their abdomen with their hind legs, and these hairs irritate the eyes or skin of the attacker.

“But tarantulas, like most spiders, are beneficial predators that feed on other insects,” she said. “Some species even make good pets. But native species, like the Texas tan, are short-lived in captivity. Generally, however, tarantulas are low-maintenance and make good starter pets.”

Black Widows — They’re not [really] that bad

Black widow on web
Black widows are known for the distinctive hourglass shape on their undersides. (Texas A&M AgriLife Extension Service photo)

Texas is also home to another arachnid often associated with Halloween– the black widow spider.

“This spider is most commonly identified by the red hourglass-shaped mark on its underside,” said Wizzie Brown, an AgriLife Extension entomologist that serves the Travis County. “But even though its venom is highly virulent, the spider itself is very timid. Even if disturbed while it’s in its web, it tries to escape rather than attack.”

She said Texas has southern black widows, northern black widows, western black widows, and brown widows, but the brown widows are not native to the state.

Black widows can be found year-round in buildings and sheltered areas such as sheds, garages, attics and crawl spaces, she said.

“Contrary to popular belief, female black widows do not usually eat males unless they are kept together in confined spaces where the male cannot escape,” Brown said.

However, she noted, their scary reputation is at least partly deserved because the venom from the black widow is a neurotoxin that can cause anything from elevated temperature, nausea and sweating to a painful cramping and constriction of the abdominal muscles and the chest, and even death.

“Death from a black widow bite occurs very rarely, and it is more likely to happen if the person bitten is either very young or elderly,” she said. But no matter your age, it’s important to seek medical attention if bitten by a black widow.”

Daddy longlegs — Just don’t call me ‘spidey’

A group of daddy longlegs on a karst feature. The daddy longlegs, however, is usually a solitary creature. (Texas A&M AgriLife Extension Service photo)
A group of daddy longlegs on a karst feature. The daddy longlegs, however, is usually a solitary creature. (Texas A&M AgriLife Extension Service photo)

Daddy longlegs are not spiders, but arachnids more closely related to scorpions. They belong to a unique order called Opiliones, or harvestmen.

“While both daddy longlegs and spiders have eight legs, they are easy to tell apart,” said AgriLife extension entomologist Dr. Mike Merchant. “Spiders have a two-part body, while daddy long-legs have a single, fused body. And unlike spiders, daddy longlegs do not make silk and can’t spin webs.”

Merchant said contrary to urban legend, daddy longlegs are not dangerous to people because they lack venom glands.

“Harvestmen can be found on every continent except Antarctica and can be found throughout Texas, from the piney woods in the east to the deserts of the western parts of the state,” he said. “They live for about one year and feed on invertebrates and dead plant material.”

Merchant said they are called harvestmen because they are typically seen around harvest time in the late summer and fall.

“They are also called ‘shepherd spiders’ due to the males guarding the females as they lay their eggs,” he noted.

Daddy longlegs are primarily night prowlers and are usually solitary, but at times a large group will amass and form a wicked-looking dark cluster that resembles a beard. However, their most compelling feature is their legs.

“While most harvestmen species have very long legs, there are some short-legged species that closely resemble mites,” Merchant said. “Daddy longlegs have eight long legs — from one to two inches in length — extending from the body. If humans had a similarly proportioned torso, our legs would extend to a span of some 40 to 50 feet.”

He said the legs are very delicate and also serve as a means of protection.

“When a predator takes hold of a leg, it can easily detach and then continues to twitch, which both confuses the predator and gives the daddy longlegs an opportunity to escape,” he said.

Another way they protect themselves is by using their scent glands, which produce a foul-smelling fluid that helps ward off the predator.

“Alone or in clusters, daddy longlegs can look strange or even ominous, but they are completely harmless,” he said.

FACTOID: In frontier days, it was believed daddy longlegs could find lost cattle. If one was picked up by seven of its eight legs, the remaining leg would point in the direction of the missing livestock.

Invasive Bagrada bug may cause ‘stink’ in South Central Texas

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by Paul Schattenberg, Texas A&M AgriLife Communications

Bagrada bug on white paper
The Bagrada bug, an invasive stink bug which feeds primarily on plants in the cole family, such as broccoli and cabbage, has been found in South Central Texas. (Photo by Dr. Salvador Vitanza)

SAN MARCOS — The Bagrada bug, Bagrada hilaris, an invasive stink bug that has been slowly spreading through the southwestern U.S. for the past decade, has recently been reported in Hays County, said a Texas A&M AgriLife Extension Service entomologist.

“This bug can cause serious crop damage as well as cause damage to plants in commercial nurseries and home gardens and landscapes,” said Molly Keck, AgriLife Extension entomologist and integrated pest management specialist, Bexar County.

Keck said adult Bagrada bugs have the same coloring as harlequin bugs, but are about one-third to one-half their size with smaller orange markings and no white markings.

She said the Bagrada bug is primarily a pest of cole crops in the mustard family, or Brassicas, including brassicaceous weeds such as wild mustard.

“Bagrada bug prefers plants such as broccoli, cabbage, cauliflower, collards, kale, radishes and brussels sprouts,” she said. “However, it is also known to feed on cotton, Sudan grass and Bermuda grass.

Keck said the bug has needle-like mouthparts used to penetrate and feed on plants and young seeds. They can cause a range of damage from leaf spotting, wilting or stunting, which can result in the plant not producing a flower, heads not forming, or even death of the plant.”

She said a high concentration of Bagrada bugs can significantly damage young broccoli and cabbage plants left unprotected in as few as two to three days.

“This pest is certainly capable of producing the kind of numbers needed to cause this type of damage,” she noted.

The recent identification of the pest in Hays County, however, is not the first instance of the bug being found in South Central Texas, said Wizzie Brown, AgriLife Extension entomologist for Travis County.

“The Bagrada bug has also been identified in the Austin area,” she said. “We’ve had reports of the bug from residents who have home gardens or who tend community gardens. The bugs appear to have shown up sometime late last year and then sprang up again on some cole crops this spring. Some people reporting them thought they were baby stink bugs.”

Bagrada bugs gather on plants and lay their eggs one at a time or in small clusters on the underside of leaves and stems or in soil beneath the plant. The eggs start out white and turn an orange-red as they get older. Young Bagrada bugs change color from bright orange-red to near black with red markings as they get older. Newly molted nymphs are also red but quickly darken to a near-black color with the white and orange markings.

Keck said early detection is important as bug populations can build quickly, but can be difficult because they are small compared to other vegetable pests and may be easily overlooked until populations become large.

“It’s usually difficult to observe Bagrada bugs until there’s been some damage, so look carefully for damage like light green lesions, which are easier to spot than the insects during the early period of infestation,” she said. “If you’re a home gardener, be sure to inspect plants and shipping containers for the bug or signs of possible bug infestation before you plant.”

More frequent monitoring for the bug may be necessary when temperatures rise above 75 degrees, as the bugs are typically more active and visible during the warmer parts of the day.     In gardens where the pest is present in large numbers, Keck said it may be advisable to remove host plants and replace them with plants not in the mustard family.

Keck said while some control methods may include picking the bugs off by hand or using a hand-held vacuum cleaner to remove them from the plants, it is often easier to tap the plant and let the bugs fall onto a cloth in order to collect them. Also, pyramid traps baited with crushed sweet alyssum inside polypropylene bags can be used to catch and destroy these bugs, especially when in large numbers.

In larger production systems, cultural control methods such as weed control and planting transplants as opposed to seeds may reduce populations and damage by Bagrada bugs.

“Stink bugs are difficult to manage with insecticides and repeat applications are often necessary,” Keck said. “Adult bugs usually fly away before they contact the insecticide and return later. Home vegetable growers will probably have better control by using plant covers or screening to exclude the bugs — or by removing host plants from the garden.”

Keck said if insecticides are used in a home garden or landscape, be sure to check the pesticide label to make certain the product is registered for use in that specific application. She noted there has been some success using pyrethrum to suppress adults while azadirachtin and insecticidal soaps have been shown to help reduce nymph populations.

She said experience with the bug on commercial cole crops in conventional field vegetable production in Arizona and California has shown success using carbamate, neonicotinoid, organophosphate or pyrethroid insecticides for control.

However, she noted, most Organic Materials Review Institute-approved pesticides are unable to control Bagrada bug.

For agricultural purposes, pesticides with quick-acting contact activity such as pyrethroids may provide good short-term protection against Bagrada bugs feeding on emerging leaves and transplants, Keck said. Once transplants become established, foliar sprays of pyrethroids and neonicotinoids should help prevent further feeding damage.

“Of course, while these bugs may move to other areas on their own, it is important people don’t help them by inadvertently transporting infested plants or produce into new areas,” she said.

Monarchs on the Move In Texas

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by Steve Byrns, Texas A&M AgriLife Communications

SAN ANGELO – Tens of thousands of monarch butterflies have been migrating through the Concho Valley in recent days, and a Texas A&M AgriLife Extension Service entomologist hopes Texans stop to appreciate what he terms is truly a royal procession.

Monarch butterflies rest on a pecan tree during their annual fall migration through the Concho Valley. (photo by Steve Byrns)
Monarch butterflies rest on a pecan tree during their annual fall migration through the Concho Valley. (Photo by Steve Byrns)

“These are special insects, and they are moving through our country here in San Angelo in a big way,” said Dr. Charles Allen who is headquartered at the Texas A&M AgriLife Research and Extension Center at San Angelo. “There were literally thousands of them in the trees at the center here, probably 10,000 or more. And then a cold front moved through, and they’re all gone.”

Allen said San Angelo is a bit west of their annual migration route to Mexico with their main thoroughfare roughly paralleling Interstate 35 through Central Texas.

The butterflies at the AgriLife center, which covered the large pecan and oak trees in places more densely than the leaves, seemed fearless and remained undisturbed by the many birds in the area. Allen said that’s because they have a not-so-secret weapon, one of their two main features the entomologist said makes them special among all other animals.

“The monarch as a caterpillar feeds on milkweed. Along with nutrition, the larva obtains milkweed protective chemicals, which it holds within its body even as it changes into a butterfly. These chemicals affect anything that might want to eat it either later as a butterfly or as a larvae or caterpillar,” he said.

“The compounds don’t taste good, and birds eating them become sick, though they don’t die, so they quickly figure out that this brightly colored insect that’s floating peacefully through the air is not food, and they don’t eat them.”

“And not only will they not eat a monarch butterfly, they won’t eat anything that even looks like a monarch, so a number of insects have evolved to look just like a monarch because they are afforded the same respect and protection. That’s pretty special.”

But there’s something even more special about the monarch, Allen said. It’s their incredible 2,000-mile migration, which is unique in all of the animal kingdom.

“All the monarch butterflies we see and enjoy in our area, in fact all those across the eastern half of the U.S. winter in a small area of only about 10 acres southwest of Mexico City,” Allen said.

But if that is not incredible enough, Allen said the butterflies being seen headed toward Mexico now have never been close to Mexico, nor have their parents or grandparents.

He said each spring the monarchs leave Mexico heading north. They lay eggs on milkweed, the adults die, the eggs hatch, the larvae feed on the milkweed and become butterflies. This cycle occurs three more times as they head up through Texas, Oklahoma, Kansas, Nebraska and on up through Minnesota, Michigan and finally Canada.

“The ones that emerged in September in Canada are the ones we are seeing now here in San Angelo,” he said. “They are the world-class travelers, the ones now heading to Mexico. They are the great, great grandsons and granddaughters, four generations removed from those ancestors that started the cycle just last spring. So none of these butterflies or even the three previous generations have ever been to Mexico, a roughly 2,000 mile one-way trip. And yet with a ‘brain’ smaller than the tip of a fine pencil lead, they know right where to go.”

Allen said past experiments have purposely taken tagged butterflies 1,000 miles off course and even with that detour, they end up in Mexico on that roughly 10-acre plot.

“It’s just an amazing feat, and that’s another reason why monarchs are royal in my opinion,” he said. “No other insect or animal does that. Four generations out and they still know their way back to their historic overwintering grounds, a place this generation has never seen before. It’s an amazing story.”

But all is not well in the kingdom of the monarch, Allen said. Their numbers are falling, and the proof of that is easy enough to determine.

“The number of monarchs are determined by measuring that small acreage in Mexico. That’s done from photos taken from airplanes or even via satellite. They measure the size of the land area that turns from the green of the foliage to the orange of the butterflies as the insects arrive and roost on the trees. By this we know their populations are down significantly, over 90 percent, from what they were 15 years ago. Fortunately, during the last two years we have seen their numbers recover somewhat, but they are still less than 50 percent of what they were before.”

One of the reasons is they are dependent on very large-trunked old forest trees at their overwintering site, Allen said.

“Those large trunks or boles are heat sinks,” Allen said. “And when the occasional cold snap moves through the area, heat radiating from those large trunks enable the butterflies to survive.

“The area is a preserve and very dear to the people of Mexico who celebrate the butterflies’ annual return, which coincides with the annual Dia de Los Muertos or Day of the Dead celebration. The monarchs are said to represent the souls of departed ancestors returning for the annual visit.

“But that area has been plagued by illegal logging activities,” Allen said. “Hopefully, the attention in the media and elsewhere is bringing the plight of the monarch into focus and will help the Mexican government protect those trees that are so important to the survival of this species.”

In the U.S., Allen said, a lawsuit filed in early 2016 to declare the monarch a threatened species targets farmers use of genetically modified crops and herbicides associated with the loss of milkweed, the larvaes’ primary food source.

“It’s not a problem with the generation of monarchs that reproduce in Texas as we grow a lot of milkweed on our vast native ranges,” he said. “The problem comes with successive generations trying to reproduce once they reach the Corn Belt. Herbicides we are using there nowadays are really pretty effective on milkweed, so there’s less of a food resource than there once was.”

Allen said this issue is currently being countered by a wide array of programs and media attention since the word got out that this butterfly is special and at risk.

“Now people are planting lots and lots of milkweed along roadsides and really any kind of a little patch that’s not being used for something else,” Allen said.

“We’re seeing a groundswell of support now to preserve the monarch,” he said. “And I think if I’m a judge, we are experiencing some of that success right now as the butterflies move through our Concho Valley area. They’re migrating in huge numbers, and I’m going to be really surprised if the acreage in Mexico that’s colored orange does not show an increase now and hopefully for years to come for the regal and very special monarch butterfly.”