Monday, July 13, 2020
July 13, 2020

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Help garden insects thrive

Tiny, numerous critters can enrich garden experience

2 Photos
Stokes aster is among long flowering summer perennials that will keep the gardener and the pollinator sustained.
Stokes aster is among long flowering summer perennials that will keep the gardener and the pollinator sustained. MUST CREDIT: Washington Post photo by Adrian Higgins Photo Gallery

I suspect the mass consciousness has shifted to a kinder feeling toward insects, and with it an understanding that most insects enrich the gardening experience.

And there are a lot of species. You will find more than 90,000 specific insects.

There are insects none of us want, starting with the ones that want to snack on us — mosquitoes and biting flies, for example — and those that want to snack on our beloved plants. Legions of professional entomologists fret about sawflies, ambrosia beetles, scale insects and leafhoppers. But the home gardener can be more relaxed. When I realized my carrot crop was being attacked by grubs, I starting harvesting them in bulk and found different ways to consume them. The carrot soup was particularly good.

Even when the pests are unwelcome, you can still find them interesting and pretty. I am thinking of the harlequin bug (a real pest of kale), the hornworm growing fat on your tomatoes and even that bejeweled scarab, the Japanese beetle.

Other insects actually help the gardener, not just with pollination and fruit set but in killing off parasites. I have come to distinguish between the tiniest bees and wasps and consider it a thrill when a tiny, iridescent sweat bee lands on the back of my hand for a quick slurp.

As a class of organisms, insects are obviously successful — they were flying, crawling and swimming around this planet long before we showed up. So apart from the honeybee, the monarch and a few bumblebee species, it seems unlikely that insects would be in as much trouble as other life-forms or their habitats in the scary so-called Anthropocene, if only for their sheer numbers and species diversity.

But for years, reports have argued that many species are disappearing, and more recently there has been much talk of a dire collapse of the insect world, fueled by some high-profile published studies.

A 2017 study in Germany recorded a 75 percent reduction in the collection of insects, by weight, in 63 nature preserves in less than three decades. This year, a review of 73 scientific papers spoke of a decline so rapid that if it went unabated, insects would suffer a mass extinction.

This spurred other scientists to pick large holes in the predictions, saying the findings and their interpretations were flawed.

What is needed, they say, is a better understanding of baseline populations that will give future declines more context. About 1 million insect species are scientifically recognized, but that is a fraction of the true number. Estimates range widely. A conservative figure is 5.5 million.

Matthew Forister, an ecologist at the University of Nevada, is among those who believe we can’t wait for complete insect tallies to protect them. He is the co-author of a new scientific review that argues that declines in insect diversity and abundance have been well demonstrated; in North America, 28 percent of bumblebee species are considered threatened and 19 percent of butterfly species are at risk of extinction. Moreover, he told me, we know that climate change, habitat loss and pollution are harming animals and plants, and it is logical to assume that the mostly uncharted world of insects is imperiled too, especially when you consider that pesticide use on the planet has never been higher. The paper was written with Emma Pelton and Scott Hoffman Black, both of the Xerces Society for Invertebrate Conservation.

“This is similar to climate change and tobacco [its link to cancer] in that we have forces out there that want to make it more complicated than it is and say we don’t have the data we need to make a decision,” said Black, the society’s executive director. “We feel being paralyzed by indecision will only make it worse.”

He said a few prescient voices in the 1980s were warning about climate change. “If we had taken action then we wouldn’t be in the situation we are now with climate crisis,” he said.