Posted by Ed Robinson | Sep 14, 2022 | Columns

The hairs of the browntail moth caterpillar can cause skin irritation and headaches, even breathing problems. (JULIA MCLEOD PHOTO)

Pete was lunching along the shore of Cobscook Bay near Lubec, enjoying a fine view. Suddenly he felt a sharp sting, then another. Pete noticed tiny red ants crawling up his legs, clearly with painful intentions. He brushed them off, wondering what triggered the attack.

Trigger warning: If you suffer from entomophobia, the fear of insects, please stop reading!

Surprisingly, the attackers were fire ants. My troubles with native fire ants occurred in Texas and Colorado. In fact, these invasive European fire ants are found in a number of spots along our coastline. They give a nasty bite to animals or humans, causing a sizable rash or allergic reactions. They are aggressive and destructive to native ants. Unfortunately, the fire ants have plenty of invasive colleagues.

You may know about the Lone Star tick, winter moth, hemlock wooly adelgid and browntail moth. All came to Maine from abroad or from southern U.S. locations. For now, the worst is the browntail moth, which landed in Massachusetts from Europe in 1897 and spread in southern Maine to cause defoliation of oak and fruit trees. A toxin found on the fragile barbed hairs of the browntail moth caterpillar can cause skin irritation, headaches and breathing problems. Protect yourself from the hairs while outdoors, and by carefully removing larval nests in late winter.

More recently we have the emerald ash borer, a metallic-green Asian beetle identified in Michigan in 2002. In 20 years, it moved into 35 states and caused the loss of hundreds of millions of ash trees. The larvae feed under the bark of trees, eventually killing them. While the beetles disperse naturally via short flights, their spread has been aided by the illegal movement of firewood, untreated lumber and landscaping plants. Maine has tried to limit the infestation, banning firewood imports and using traps and insecticides, but it appears that nothing can hold back the tide. Longer term, biological controls may help those few ash trees that avoid destruction.

Maine hosts other invasive bugs, including the southern pine beetle, found in 2020, and the spotted lantern fly (also known as the Chinese lantern moth, although it is neither a fly nor a moth), confirmed in 2019. The pine beetle arrived from the southern U.S., probably thanks to our warming climate. It is a major concern because of cyclical outbreaks that can destroy millions of acres of pines while creating forest fire risks. The lantern fly arrived in Pennsylvania from China in 2019 and targets mostly fruit trees and grapes.

The aptly named leek moth arrived in Rangeley in 2019, putting its namesake plant at risk. Fruit, nut and vegetable crops are also at risk from the brown marmorated stink bug, now found in almost every state. There is some hope of eventually controlling this bug thanks to its natural predator that also arrived from Japan, the tiny, colorfully named samurai wasp.

The news media will often highlight a potential new insect invasion as a way to grab eyeballs or boost ratings. A few years ago, it was the potential arrival of “killer bees,” Africanized bees with a bad attitude and wicked stings. More recently we have read about the expected arrival of the Asian longhorned beetle, European giant or “murder” hornets, and the palm-sized Joro spider, parachuting into Maine on wisps of silky web. So far we have been spared these invaders.

If this all sounds like the “revenge of the bugs,” it may be so. Years of indiscriminate human development and widespread use of synthetic agricultural chemicals have created imbalances in our environment. The fact is that insects have been on a relentless march for millions of years. Their numbers are in constant flux as the world’s climate cycles up and down while predators emerge or disappear.

Insects like the gypsy moth can be hugely destructive in the early years of infestations, but they often reach an equilibrium with a much lower rate of forest damage. While the loss of most of our ash trees will be devastating for native basket weavers and baseball bat makers, Mother Nature always fills a void with other species. We have a role to play, with actions as simple as using only local firewood when camping, and responsible control of pests around our homes, or as complicated as trying to slow global warming.

Note: The University of Maine maintains an excellent website for its Cooperative Extension that lists invasive insects with many links for more information.

Ed Robinson’s latest book, “Nature Notes from Maine Vol. II: Puffins, Black Bears, Raccoons & More,” is available from the Harpswell Heritage Land Trust. All profits support HHLT’s conservation and public education efforts.

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