–Dr. Chris Looney, entomologist with Washington State Department of Agriculture
Photos courtesy of Washington State Department of Agriculture
There’s no better diversion from an enormous quarantine and scary disease than an enormous and scary stinging insect. We may not know for sure if the Asian giant hornet (Vespa mandarinia) is here to stay, but that sure hasn’t kept people from worrying about it. One of 22 species of the genus Vespa – none of which are native to North America – the Asian giant hornet is native to Asia, where it ranges from Hokkaido to Korea, south to Taiwan, and west along the Himalayas. It is a social species, with a single breeding queen living in a nest maintained by her worker-daughters. The workers collectively raise the colony’s larvae in their underground lairs, feeding them mashed up beetles, caterpillars, and other insects captured by these effective predators.
Asian giant hornets are also known for their fairly unique behavior of collective attacks on other social insects, particularly honey bees. This occurs in late summer or early fall, when the colony is ramping up production of the next generation of queens. In these group attacks hornets target a single hive, capturing any defenders, snipping their heads off with their mandibles, and casting the bodies aside. A handful of hornets can destroy most of the workers in a beehive in under two hours, leaving the defenseless bee grubs and pupae to be carried back to the hornet nest to become food for hornet larvae. Most of these late season baby hornets will become queens and males, who leave the dying nest and mate. Each mated queen disperses to overwinter, and if fortunate, will found a nest of her own in the spring. 
No one wants this formidable insect to become established in Washington, and robust trapping by the Washington State Department of Agriculture and the concerned public will help us figure out what kind of risk we really face from… murder hornets!
Check www.agr.wa.gov/hornets to stay informed.