Backyard Naturalist: Worrying observations in a summer bug report

The burying beetle (Nicrophorus genus, a kind of carrion beetle) is not as prevalent as it should be this year, which may indicate a cause for concern, according to Dana Wilde. Photo courtesy of Bob Nelson

This summer’s bug report so far is summed up in two words: not many.

On the face of it this seems like good news. Fewer wasps wondering if they should attack us to protect their nests as we go in and out the front door. Black flies swarming for just a few days, where they used to linger for weeks. Mosquitoes, as always, but fewer. Like last summer, there’s a paucity of deer flies and horseflies trying to tear chunks of meat out of our arms in the driveway.

This dearth of bugs makes life in the summer breezes much more pleasant. It’s also less entertaining. Dragonflies, which 10, 15 years ago filled the backyard every evening with formal aerobatic beauty, are almost completely absent again, after a slight return last year. For a week or so in June I thought the fireflies were AWOL too until lights started blinking in the wild rose hedge, maybe 10 or 12 at any given moment; 20 years ago they looked like flashing star fields. When Silas was 3, the black and orange burying beetles patrolling the compost fascinated him; for his fourth and fifth summers, we have not been able to raise any, even cheating by enticing them with chicken bones.

If all of reality were bounded in the nutshell of these few minutes we’re living in right now, an absence of insect pests would seem like an overall blessing, wouldn’t it?

Except, time is not limited to the single moment you’re experiencing right now. It extends down into the past and up into the future. (And sideways into elsewhere too; let’s talk about that another time.) For now let’s just say the past and present point inevitably to the future. And an insect-free future will be a curse.

Insects are so numerous and diverse that they’re effectively impossible to study comprehensively. But one thing the entomologists seem more or less agreed upon, as environmental journalist Oliver Milman records in his recent book “The Insect Crisis,” is that there are markedly fewer of many of them than there were about 50 years ago.

One of Milman’s many examples involves beetles. Their populations are crashing in parts of North America and Europe. A study in the mid-2010s in protected forestland in central New Hampshire found that beetles had declined by an average 83% since the 1970s. Nineteen beetle families “had vanished completely.”

Beetles, so what?

Milman explains: “Beetles perform a range of crucial roles in … forests. When a tree is felled, they help break up and chew apart the wood, allowing fungi to enter these spaces and aid decomposition. This allows the tree’s nitrogen and phosphorus to be distributed to replenish the wider forest. Some beetles also prey on other insects, keeping their numbers in check. … Without beetles, springtails (for example) proliferate and decomposition accelerates to the point where the carbon storage of the forest floor is diminished.”

I wonder if our absent burying beetles are part of this crash. If so, is it invisibly deteriorating our woods yet?

When insects disappear on a large scale, things go dangerously haywire. In Puerto Rico, researchers discovered that insect populations in various parts of the rainforest have crashed 80% to 98% since the 1970s. In turn, bird, reptile and other animal populations that all depend on bugs and each other for food have also plummeted. This aspect of the rainforest’s food chain “is in a state of collapse,” the researchers found.

If the wrong insects disappear — and many entomologists fear the documented crashes indicate some are headed for extinction — serious problems will result for humans. “More than a third of food crops grown around the world need a steady stream of insect visitors to maintain them,” Milman says. Among those visitors are bees. Milman devotes many pages to crashes in bee populations in recent years, what beekeepers think is happening and what can happen if the bees are lost.

What’s causing the problems for the insects? For the scientists, the answers are not definitive. But in Milman’s book we read quote after quote from researchers suggesting basically the same answers: misuse and overuse of insecticides (particularly neonicotinoids which are poisoning almost everything, not just pests and pollinators); habitat disruption (mainly, but not only in the form of monoculture agriculture which wipes out diverse vegetation needed by insects and birds); and climate change, in which rising temperatures and changing moisture patterns affect food sources and drive some species to new areas which they in turn disrupt.

Milman’s book provides little in-depth discussion of any one of these entomologic issues, but offers torrents of information pointing to an impending crisis. His book is a sort of summarizing patchwork reflecting the patchwork of insect research itself.

Many of the entomologists Milman spoke to seemed optimistic that problems caused by humans can also be solved by humans. Sharply reducing pesticide use — which Milman’s researchers indicate would not be as hard as you’d think — and growing crops more diversely would go a long way to curbing the disappearance of the very insects that are needed to grow the crops.

The bugs that filled bygone summer evenings were annoying, but actually a sign of ecological health. The bugless night air we’re enjoying now is very likely a sign of catastrophic illness.

If we stick our heads in the sands of time on this, it’s going to come back and bite us. It already is, actually. Not all insects are hurt by our disruptions. Some thrive in it. Like deer ticks, for example.

My doctor, who is an ant aficionado, told me last week — unprompted — that he is alarmed by the absence of bugs around his camp in Belgrade this summer. No deer flies, no dragonflies, hardly a black fly, even a noticeable lack of mosquitoes during his walks on the camp road. My friend Phil, the lifelong Maine hiker who lives in Farmington, told me black flies hardly appeared at all this year.

My spidering colleague Frank Allen in Waterboro wrote last week: “The insect population in my area is dismal. Yeah, we have a lot of dragonflies, but not many mosquitoes nor black flies. Even the deer flies are almost nonexistent.” On the Maine Entomological Society’s Facebook page, a thread of commenters noticed a startling absence of June bugs.

These are isolated nutshell observations, though. They may or may not be linked.

For my part, I can only say that hardly a moth has knocked against our screens this summer.

Really, I’d feel better about the future if the burying beetles reappeared in the compost pile and the deer flies were stabbing my arms on July afternoons.

Dana Wilde lives in Troy. You can contact him at naturalist1@dwildepress.net. His book “Summer to Fall: Notes and Numina from the Maine Woods” is available from North Country Press. Backyard Naturalist appears the second and fourth Thursdays each month.