Unexpected ally in the fight to save forest

Unexpected ally in the fight to save forest
John C. Lorson

A single bright maple stands guard amid a stand of dead ash trees decimated by the emerald ash borer. In the nearly 20 years since the invader was first discovered in North America, it has claimed an estimated 100 million trees, but help may be on the way from an unexpected source: a small predatory wasp that preys only on the larva of the destructive insect.


Out on a call to a country home for my day job in conservation, I was talking with a landowner about a drainage problem. After a walk around the property, we stood near the front porch, which was one of those big wrap-around deals with white railing and hanging flower baskets.

Between each of the flower baskets hung a red hummingbird feeder, and birds were coming and going like flights at O’Hare International Airport — I’m talking dozens if not hundreds of hummingbirds shooting like little feathered darts inbound and outbound. I was completely captivated. When one fuzzed the edge of my ball cap in a rapid flyby, I finally broke character.

“I’m sorry. We can get back to that mud hole in your yard in a moment,” I apologized. "First, you’ve got to tell me about these hummingbirds."

The owner explained that he and his wife had built the place — a bit of an oasis in a large, gently rolling area of corn and soybean fields — about 20 years before. They’d hung a hummingbird feeder they’d received as a housewarming gift, and for that whole first summer, they saw nothing but hornets and yellow jackets. The next year around mid-summer, they got their first avian visitor, a male ruby-throated hummingbird.

“And then it seemed like he went back to the bar and gathered his friends,” he said. “Hey, y’all, I found us a new watering hole. Follow me.”

The population grew from there on out, and he and his wife soon found feeding an entire squadron of hummingbirds with commercial hummingbird food (bought as liquid in a bottle) was a bank-breaking proposition. Instead they found the birds just as willing to thrive on a mixture of one part table sugar and four parts water with no need for the fancy red coloring. They now go through several 25-pound bags of table sugar a season, filling the feeders nearly every day.

I was smitten. For a guy who’d spent most of his life watching starlings and house sparrows empty his seed feeders in hopes something interesting would occasionally show up, the experience was nothing short of inspiring. I stopped by the hardware store that night and bought a hummingbird feeder, along with some of the fancy red liquid nectar, and hung the contraption right outside the kitchen window. The hornets and yellow jackets arrived within a day and laid siege to my entire patio. After a week of swatting and screaming, I took it down, vowing to try again in the spring before the wasp hordes began their annual rampage.

As I mentioned in my column last week, many social wasps including hornets and yellow jackets can be aggressive and dangerous. At this time of year in particular, that aggression leads them into conflict with humans as food sources are diminishing, hives are dispersing and, quite frankly, all of the individuals you see are dying. Only the queen lives through the winter to begin an entirely new colony. And while the feisty black and yellow invaders can be a major pain, they — as most every creature — can be beneficial to humans in some regard. In their quest to harvest protein, yellow jackets eat insects and grubs that can damage crops and gardens.

While I’m on the subject of wasps and their possible benefits to mankind, here’s a news story we can all rally around. Researchers are concentrating efforts on a certain type of small, nonstinging, parasitic wasp in the fight against the emerald ash borer, which has decimated over 100 million ash trees in North America in the past 20 years.

Not only can the wasp, a native natural predator in the ash borer’s Asian homeland, detect the larva of the beetle underneath the bark of an infected ash tree, but also it can penetrate the bark with its egg-depositing organ and inject ash borer larva with its own eggs. The developing wasp larva then consume the emerald ash borer larva from the inside out. Wasps of this nature typically prey only on a specific species, so other native insects would go unharmed. Researchers are busy looking for any possible down sides to this approach before a large-scale introduction, but the emerald ash borer’s days may be numbered.

Now back to my quest to entice hummingbirds to my home. Just a few weeks ago, we finally spotted our first hummingbird at our backyard feeder. We’re still hoping he goes back to the bar and rounds up his buddies.

Remember, if you have comments on this column or questions about the natural world, write The Rail Trail Naturalist, P.O. Box 170, Fredericksburg, OH 44627, or email jlorson@alonovus.com. You also can follow along on Instagram @railtrailnaturalist.

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