Shawn Raymundo

sraymundo@guampdn.com

A foreign species of aggressive wasp recently found on island is likely to stick around for a while, according to scientists at the University of Guam.

Eradicating the class of predator called vespa tropica, or more commonly known as the greater banded hornet, is an unlikely endeavor, given the financial resources and manpower available on island, University of Guam entomologist Aubrey Moore said during a presentation Thursday at the university.

The hornets are aggressive, especially to those who come near their colony or hive. A safe distance from the hive is about 10 meters, or roughly 30 feet.

Although there have been fatalities in other places, caused by the wasp’s venom from multiple stings, those with bee and wasp allergies are more susceptible to life-threatening danger near the wasps, Moore said.

Some of the first colonies of the banded wasps were found in Upper Tumon and near the LeoPalace Resort Guam, but there have been at least a dozen sightings within recent months, all within the central part of the island.

GovGuam develops plan to combat new hornet

Based on a delineating survey, which is meant to determine whether or not the species needs to be eradicated, Moore said it’s possible to eradicate the wasps, but not with currently available resources.

“Eradication is sometimes cheap if you find it soon enough,” Moore said during the planning meeting with several government agency heads. “I think eradication is possible, but not with the available resources.”

According to Ross Miller, another entomologist with the university, the cost to begin eradicating the wasps could range from $2 million to $5 million.

“I don’t think you can eradicate it. Insects are almost impossible to eradicate once they’re established,” he said, adding: “I’m guessing the cost is $2 to $5 million to even get started. We just don’t have those resources.”

The banded hornet prey on boonie bees — the local term for the paper wasp — and other wasp species by raiding nests and taking the other wasps' larvae back to its own nests.

Moore explained that since the wasps feed on the boonie bees, the recent influx of wasps on island is expected to balance out. But once the population of boonie bees decreases, the number of wasps on island should decline as well.

“There will be a large population of hornets, and bees will start reducing,” Moore said. “We predict that this hornet is going to become quite common over the next few years and then it will crash.”

“The bottom line is it’s here to stay,” Miller added.

Invasive wasp species found on island

To discuss ways of combating the wasps, the Department of Agriculture and the entomologists met with government officials from agencies including the Guam Fire Department, Parks and Recreation and Guam Customs and Quarantine at UOG’s agriculture building.

At this point, Moore said, they’re conducting pest control by killing the wasps with pesticides and focusing on certain areas, such as school yards and hotels.

“Based on what we know so far, we don’t want to do nothing … if it’s not in a dangerous area, then leave it alone,” Moore said. “Eradication is probably not possible without our current resources. It’s too far gone, so we’re in the middle with pest control.”

The scientists asked the department heads to let their employees and field staff know to contact the agriculture agency’s biosecurity division, which works cooperatively with the university, if a hive or colony is identified.

The banded hornet can be identified by the bright, yellow band around its abdomen. They’re about five times bigger than boonie bees. Queens can be a littler larger than an inch in size, while worker wasps average just under an inch.

When it comes to removing the hives, which are quite large, Moore and Miller stressed that it’s dangerous to do so, even with the use of pesticides. Moore said the hives are structured with layers, and then are covered, providing protection from storms.

Typical bee suits are no match for these wasps either. The banded hornet’s stinger is much longer than a bee’s and can puncture a person’s skin through multiple layers of clothing.

Just recently a group of firefighters attempting to rescue a dog trapped in a ravine were attacked by a colony after one of the firefighters accidentally disrupted a hive on his way down the ravine’s cliff.

Firefighter Brandon Sanchez, who was being roped down the ravine, stumbled upon the hive and was severely attacked, getting stung multiple times. Sanchez’s fellow firefighters, who quickly pulled him back up, also were stung.

Sanchez and GFD Lt. Vince Leon Guerrero, who also got stung, attended the meeting and noted that they had to run at least 30 to 40 yards away before the wasps stopped chasing them.

The species usually is found in China, Japan, Malaysia, Hong Kong, Singapore, India and the Philippines, but Miller and Moore said they’re still unsure how it migrated to Guam.

One possibility is the wasps came through the port from other countries, but Miller noted that it’s possible one fertile queen could have launched the entire local population.

Despite the aggressiveness of the wasps and the risk to human health, Moore said he doesn’t necessarily consider them an invasive species because they’re not an agricultural pest.

“Personally, I don’t see this as real invasive species. The bigger problems, in my opinion, are little fire ants and rhino beetles,” he said. “If we don’t do anything about it, it’s going to kill 50 percent or more of our coconut plants.”

Opinion: How to address invasive species problems in Guam