We share the world with hundreds of thousands of species of insects, most of which we never even notice as we go through our daily lives. They provide critical ecosystem services, such as nutrient cycling, being a food source for other animals, and pollination. As you become a more keen gardener, whether you are a vegetable or a flower grower, pollinators are your allies in helping your plants form higher quality fruit and reproduce!

Yet, not all of our winged visitors are native to North America, and some of them could be harmful. While many introduced insects are harmless or even beneficial, some non-native pollinators can disrupt established ecosystems and threaten native species. Understanding the potential impacts of these newcomers is crucial for protecting our local biodiversity. Let’s learn about them.

One such insect is the Sculptured Resin Bee (Megachile sculpturalis). Native to Asia, this bee has been introduced to various parts of North America. A significant concern surrounding the sculptured resin bee is its preference for introduced and invasive plant species, particularly kudzu, as pollen and nectar sources. This preference can exacerbate the spread of these invasive plants. Furthermore, it has been observed displacing native carpenter bees (Xylocopa), creating competition for resources. Perhaps most alarming is evidence suggesting that these bees can damage native floral resources during foraging. Due to a mismatch in body size and floral structure, they can unintentionally destroy parts of the flower, hindering its ability to produce seeds and potentially impacting plant populations.

The Large Earth Bumblebee (Bombus terrestris audax) presents another potential threat. This bumble bee is native to Europe, and has been widely used in greenhouse production because of its ease to raise in captivity. The danger lies in its potential escape and establishment in the wild. This species is a known vector of disease and is a strong competitor, capable of outcompeting native pollinators for resources. Its highly invasive nature has been demonstrated dramatically in Tasmania, where it has caused significant ecological problems. It is considered a major invasive threat in Australia, with a “BOLO” (Be On the Lookout) alert issued for it. Interestingly, although it was previously banned from the US and Canada, it was allowed into Mexico. Unfortunately, it has since escaped and is now spreading northward, posing a growing concern for North American ecosystems.

The familiar European Honey Bee (Apis mellifera), while widely established and often considered beneficial for agriculture, is itself a non-native species. Brought over from Europe, it has become an integral part of our agricultural landscape and local economies. While providing valuable pollination services, its presence can also create competition for native pollinators, especially in areas with limited floral resources.

Moving beyond bees, several non-native hornet species are raising concerns. The Yellow-legged Hornet (Vespa velutina) is native to Southeast Asia and was originally detected in Georgia, and has since been found in South Carolina. The North Carolina Department of Agriculture and Consumer Services is currently on the look out for this insect in North Carolina, in an effort to eradicate it before it can become established. This hornet is a predator of other insects, but most importantly including honey bees, and could have significant impacts on both managed and wild bee populations. The critical point about this species is that it can look like many other native and non-native hornet and wasp species, so it is important to have the specimen identified by an entomologist.

The European Hornet (Vespa crabro), another European native, is already established in North America, including Lee County, where it is typically observed in August and September. While not as aggressive as the yellow-legged hornet, its presence still contributes to the overall pressure on native insect populations.

Finally, the Northern Giant Hornet, also known as the “murder hornet” (Vespa mandarinia), native to most of Asia, garnered significant attention due to its large size and predatory behavior when it was detected in the U.S. Fortunately, after initial detections in Washington State, it has been successfully eradicated. This eradication effort highlights the importance of rapid response to invasive species threats.

The introduction of non-native pollinators, while sometimes unintentional, can have far-reaching consequences for our ecosystems. Understanding the potential risks associated with these species is crucial for protecting our native pollinators and the vital services they provide. By staying informed and supporting efforts to monitor and manage these introduced species, we can help preserve the health and diversity of our natural environment.

Amanda Bratcher is the horticulture agent with N.C. Cooperative Extension- Lee County Center. If you have any questions or comments about this article, please reach out to the Extension Office at 919-775-5624.