Northern Giant Hornet
The Asian giant hornet (Vespa mandarinia) was recently detected in western British Columbia, Canada and Washington State, United States. V. mandarinia are an invasion concern due to their ability to kill honey bees and affect humans. In September 2019, a Vesp mandarinia nest was found on Vancouver Island, British Columbia, Canada; later that year, four workers were found in Washington State, United States. In 2020, three additional queens were found. Introduction of V. mandarinia in North America is concerning because honey bees are highly vulnerable to hornets. V. mandarinia is also medically important, delivering painful stings with cytolytic venom. It is currently unclear if V. mandarinia is established in North America and efforts are underway to identify introductions and prevent spread. Mitigation efforts for V. mandarinia would be most effective if global habitat suitability, and potential dispersal into areas with high human activity, were characterized. We modeled responses of V. mandarinia to climatic variables and simulated potential invasive spread, this work was published in late 2020 at PNAS.
Figure 1. Dorsal (a) and lateral (b) view of Northern Giant Hornet (credit: https://agr.wa.gov)
Potential geographic distributions in Washington State
We used habitat suitability models and dispersal simulations to assess potential invasive spread of V. mandarinia. We show V. mandarinia are most likely to establish in areas with warm to cool annual mean temperature, high precipitation, and high human activity. The realized niche of introduced populations is small compared to native populations, suggesting introduced populations could spread into habitats across a broader range of environmental conditions. Dispersal simulations also show that V. mandarinia could rapidly spread throughout western North America without containment. Given its potential negative impacts and capacity for spread, extensive monitoring and eradication efforts throughout western North America are warranted. Here is the potential distribution of Northern giant hornet in Washington.
Figure 2. Potential distribution of Northern Giant Hornet in Washington State.