Stowaway hornets discovered in Saipan

On March 21, 2000, a swarm of exotic hornets made their way to Saipan via a shipping container from Washington State. At the time of discovery, some hornets escaped into the neighborhood, causing a real buzz among local Department of Land and Natural Resources officials.

Inspectors from the CNMI Plant Protection and Quarantine (PPQ) division engaged the assistance of the NMC-CNMI Cooperative Research, Extension and Education Service (CREES) Lab where they turned in dead invading hornet specimens. Dr. Lee Eavy, an entomologist of the NMC-CNMI CREES, immediately took charge and started analyzing and identifying the species.

After thorough examination, and with the help of colleagues through the Internet, Dr. Eavy identified the species found in the container to be vespula acadica , also known as the forest yellowjacket.

“It turns out that this species is probably not a major threat to our island,” Dr. Eavy reports. “This species will be a minor nuisance if it is able to establish a colony here. This is because these hornets are known to be natives of cold climates such as the northwest forest regions of the United States and Canada.

These forest yellowjackets are twice the size of our local hornets. They prey on caterpillars and other arthropods, but can also be a nuisance during outdoor activities. These particular yellowjackets do not nest in trees or high areas, but they do nest in grassy fields building their nests using leaves and grass. These nests look like old paper bunched up on the ground, in some cases they look like little piles of dirt in an open field.

Great caution should be taken if any of these nests are found. Parents should be wary when their children play in open fields, since these nests can be mistaken for paper, trash or dirt. The forest yellowjackets are well known for stinging people really hard. In some instances once the nests and hornets are disturbed, they could literally sting you to death.

As a precautionary measure, Dr. Eavy is in the process of chasing down the newest trapping and luring technologies from USDA. In addition, he is working on setting up a monitoring program to track down these exotic hornets. He also expressed that he would like to eliminate as many forest yellowjackets as possible using traps.
In order to make sure that no other forest yellowjackets could escape, the container was fumigated twice, once by Dr. Eavy, and once by a local exterminating company.