Homestead
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Every June, dozens of monarch butterflies descend on Lee Davis’ yard in Orono — every June but this one.
Davis, who has let a patch of milkweed spread to help feed the migrating pollinators, has noticed the milkweed tussock moths that usually crowd the plants are also missing. So are some less welcome insects, she said, like Japanese beetles and browntail moth caterpillars. Friends haven’t seen many monarchs either.
“Why haven’t they come?” she said. “What’s going to happen to the population?”
Reliable, long-term data about the populations of the thousands of insects in Maine is generally limited, individual observations don’t necessarily indicate trends, and many factors can influence their behavior, according to naturalists.
But numbers of insects — which pollinate plants, including crops, and fill a key role in the food chain — have declined sharply worldwide in recent decades, and it’s having noticeable impacts in Maine.
“Whether you care [about insects] or not on a species level, every living human should care if you want to keep living,” said Doug Hitchcox, a naturalist at Maine Audubon. “We need insects.”
He’s noticed people caring more since a 2018 New York Times Magazine article titled “The Insect Apocalypse is Here,” which highlighted dramatic drops in the numbers of insects worldwide amid habitat loss, pesticide use and the effects of climate change. Some entomologists have said talk of an apocalypse is “over-hyped,” but should be a call to action.
At the opening of that article, a bicyclist realized he was no longer eating bugs while riding like he did among clouds of insects as a boy. The story also highlights the “windshield phenomenon:” people’s memories of needing to clean bugs off their windshields after driving just a few decades ago, compared to rarely, if ever, today.
Anecdotes like that indicate something has changed — and there’s no denying a problem exists, Hitchcox said — but there’s limited consistently collected, long-term scientific data that can clearly show its impact in Maine.
Worldwide, more real research has been done in recent years to quantify those declines. A few studies showed dramatic drops: the monarch butterfly population declined by 90% over 20 years, the abundance of flying insects in German nature reserves had decreased by 75% in 27 years, the volume of insects in Puerto Rico had declined 10 to 60 times since the 1970s and so on.
Such studies helped prompt local work to try to zero in on Maine-specific datasets, Hitchcox said. The handful they located show changes including declines in flowerflies, several species of which the state recently added to its special concern list — indicating they could easily become endangered. A new population survey is ongoing.
The number of different butterfly species is declining, but the overall number of butterflies is staying flat. Plants are still getting pollinated, but if species are being lost in the process, it probably indicates a loss of the host habitats and plants that support them, according to Hitchcox.
Monarch butterflies, which migrate north from Mexico in multigenerational cycles, have actually shown an increase in numbers at southern monitoring sites in recent years, he noted.
One tangible Maine example appears in birds. The state’s multi-year Maine Bird Atlas project, published this year, updates a similar effort conducted in the late 1970s and early ‘80s to catalog species.
Some showed obvious declines — 60% or more in some cases — including among species that primarily eat insects, like swallows. That was consistent across different habitats and even among non-native birds, meaning a loss of bugs is the cause, according to Hitchcox.
People sending photos of what they see to crowd-sourced “community science” projects and recording them on sites like iNaturalist is also very valuable, in his view, and something anyone can do to help.
“Ultimately, what we need is just more data,” he said.
And, though invasive insect species have increased here, it’s likely not to a replacement level, and the diversity of individual species is still being lost, according to Hitchcox. Among the invasive species that have drawn attention in Maine in recent years are spruce budworm, emerald ash borer, and browntail moth caterpillars.
Roger Rittmaster, a master naturalist and insect photographer who lives in Camden, said he and his fellow insect enthusiasts have “definitely” noticed fewer insects in general this year — but he’s not sure that’s due to an “insect apocalypse.”
But, “over the longer term, it’s obvious there are fewer insects,” he said.
It’s hard to track differences quantitatively, he said, and many factors can influence various species; this cold winter and spring may have reduced some numbers, he suggested.
Rittmaster was away from home for most of June and didn’t see any bumblebees upon his return, but now they’re “all over” and seem to be doing very well. He’s hardly noticed any monarchs, either, but he expects them later in the year as fall approaches; butterfly appearances, he said, tend to fluctuate.
Rittmaster also recalled the windshield phenomenon, too: decades ago, he cleaned insects off his car almost daily in the summer, but guessed Tuesday that it’s now been a month since he last needed to.
Hitchcox, the naturalist, does see reasons for optimism.
Though he’s skeptical of the interpretation of existing environmental protection laws and the likelihood of pesticide restrictions advancing under the Trump administration, he noted the country has helped remedy federal past environmental harms, such as by banning DDT and introducing the Endangered Species Act. Restrictions on the use of neonicotinoids, which are pesticides that also harm numerous pollinators, have recently been enacted or considered in several states including Maine.
Then there’s increasing enthusiasm for growing native plants, which are typically host to many more insects, providing habitat and food to a wide diversity of species compared with their imported counterparts.
Planting a few native plants is one tangible step that anyone who owns land can take to help insects, Hitchcox said; so is contributing to community science projects and even simply using less insect repellent.
For more than a decade, Rittmaster has been cultivating his Camden yard to attract more insects, where he’s now photographed more than a thousand species.
“The key is native plants,” he said.
