As summer approaches, I often think of my childhood in Maryland in the 1970s, and invariably I think of fireflies. Most of the outdoor spaces in my neighborhood were tamed spaces – mowed lawns and manicured gardens. However, some were left wild and in the summer these wild spaces overflowed with growth.
Dark green honeysuckle vines, the glossy leaves of poison ivy, the bright orange threads of the plant parasite known as dodder, are said to drape over shrubs and creep into trees. And all this growth was a haven for insects. As night fell and I looked out across our back lawn to the undergrowth, I could see a few flashes of firefly light and then, as the sun slipped further down, I would see so many more, twinkling and streaming against the darkening background.
The fireflies were certainly not alone. The flashing of their lights was accompanied by the chirping of crickets and the screeching of grasshoppers, a cacophony of insect sounds that melted into a uniform buzz in the air. The sound betrayed to our ears the sheer number of insects there and what an astonishing variety. The show these bugs put on was the most punk rock performance I’d ever witnessed. It started before sunset, lasted until sunrise, obeyed no boundaries and followed no rules. The same heat and humidity that slowed down the pace of our lives was an accelerator for the insects. They pupated and emerged, some after years underground, for a raucous feast, voracious consumption and a race for reproduction.
The show these bugs put on was the most punk rock performance I’d ever witnessed.
Are summers full of insect sights and sounds a thing of the past? Environmentalists have been measuring wild insect populations for decades. The news has been bad in recent years. In Current Biology in 2019, insect ecologist David Goulson cites studies done in Germany and Puerto Rico that report a staggering decline over the past quarter-century in both total insect biomass and species diversity. In one of these studies, the total insect biomass collected by researchers in the wild in 2014 was less than a quarter of what they had used at the same site in 1989.
Goulson points to several economic reasons why we should pay attention to the decline of insects. He notes, for example, that three-quarters of the crop species we grow require insect pollination, “a service estimated to be worth $235 to 577 billion a year worldwide.” He further appeals to our sense of natural wonder and asks: Don’t all species have as much right as we do to be here on Earth?
Why is it happening? The suggested causes of insect decline are all too easy to imagine. In a research paper published in April this year in the journal Nature, Outhwaite and colleagues reported that insect declines are worst in those places on Earth where large-scale farming and the impacts of climate change coincide. A glimmer of hope comes from Outhwaite and colleagues’ observation that the presence of natural spaces near low-intensity agricultural use sites — spaces similar to the wild patches bordering grass clippings in my old Maryland neighborhood, but on a much larger scale – dampens the declines compared to sites that have no coverage nearby.
The decline in insect populations is worrying. The problem is one of many symptoms that we are not treating our planet the way we should be. Like a nature-loving kid who grew up to be a biologist studying an insect (the fruit fly) Drosophila melanogaster), I find it to be a symptom of environmental stress that resonates with me in particular.
I believe that radical societal change on a global scale is needed to save ourselves – and the fireflies, the crickets, the grasshoppers and so many other invertebrates – from environmental destruction and climate change. Still, I wonder when our society will bend to meet the need.
How quiet should summer evenings get? How devoid of the magical flashes of light? The chaos of sound? The raw life of the little ones?
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