“It’s grim, but it’s not too late” to bring back the insects on which the world depends. 05/13/2021
“When I was a teenager, there were bugs all over my windshield when I drove anywhere,” says my editor Brad Lemley. “No more.”
Brad, a boomer, grew up in Oregon’s Willamette Valley, where dragonflies, yellowjackets and great clouds of gnats were once plentiful.
To be sure, there are still bugs about. This month, if you live in the eastern United States, as far west as Illinois and south into Georgia, you might find some cicadas on your car – large, messy victims of instant acceleration. Brood X, a batch of cicadas that emerges every 17 years, is getting its turn to molt, mate and lay eggs before its babies burrow underground. Cicadas are loud, which can annoy. But they are not locusts and they won’t wipe out our crops or gardens or even sting (Whitt, 2021).
The big risk: they might frighten your small children or grandkids. Bugs, you might explain to them, are often essential. They pollinate, break down waste, and move seeds. They bring us medicine and protect forests and farms by fighting pests. They are food for birds and small mammals, and fertilize plants with their waste and decaying bodies. As an international team of scientists wrote, “The fate of humans and insects intertwine” (Samways, 2020).
But while we intertwine, we humans are too often tangling up and strangling our bug friends. The world’s 10 million species of insects are threatened by shrinking forests, industrialized agriculture, light pollution and climate change. A 2020 meta-analysis published in the journal Science, suggested that worldwide, insect numbers are dropping about nine percent per decade (Van Klink et al., 2020).
The declines Brad has noticed are steady and staggering, yet there’s still hope (Halsh et al., 2021).
Bumblebees and other good bugs in a warming world
Pollinators like the bumblebee fertilize not only wildflowers but tomatoes, blueberries and squash. Bumblebees’ wing muscles make heat when they fly, a competitive edge that allows them to be the first bees out in the spring.
That can mean warmer weather is a big problem for them. The rusty patched bumblebee, once common in Ontario, has disappeared from Canada and is endangered in the United States. In North America, you have roughly half the chance of seeing a bumblebee as you had before 1974 (Soraye, 2020).
Through changing temperatures, trouble has come to insects in areas far from ordinary human activity. In a protected hardwood forest in New Hampshire, for example, the number and diversity of beetles have dropped dramatically since the mid-1970s, as the air warms and there’s less snow to insulate them during the winter (Harris et al., 2019).
Some insects benefit from the new conditions. As the water temperature rose in a headwater stream in a German nature preserve, the overall numbers of insects fell by 82 percent, yet diversity increased (Baranov et al., 2020).
Butterfly populations had been falling at low elevations since the 1990s in northern California. When four years of record drought came in 2011, the population in the mountains plunged and the lower-lying butterflies recovered a bit (Forister, 2018). Monarch butterflies did well in those drought summers because they had more time to reproduce. And the brilliant orange-and-black gulf fritillary butterfly is now thriving in California, where people are cultivating its host, the passion vine.
But the fate of the large marble butterfly, which lives on mustard plants, is more typical: it is dying out, hit by climate change, pesticides and a shrinking habitat.
Bad bugs may need love, too
Some bugs you don’t want to see. Last year, Americans were visited in unfamiliar spots by unwelcome guests. “Murder hornets,” also known as Asian giant hornets or Vespa mandarinia, appeared in Washington state, their first arrival here.
Growing up to two inches long, these hornets can kill if they sting you more than once (Willingham, 2020), though a more typical reaction in non-allergic people is intense pain that can last for days. They can also decapitate honeybees and seize a hive in two hours. Although climate change may not have brought them, it will make the United States a more attractive destination, noted James Carpenter, a curator of wasps at the American Museum of Natural History in New York (Banks, 2020).
In the fall, a puss caterpillar showed up in Virginia, far from its usual habitat in the far South and Midwest, possibly because of climate change. Its brown fur oozes poison that can give you a rash, or even induce vomiting and fever. A hammerhead worm, which produces the same poison as the pufferfish, appeared in Georgia (Willingham, 2020).
Warmer weather makes some insects eat more and, outside of the tropics, could make them reproduce faster. In temperate, crop-growing regions around the world, their extra activity could cost us a 10 to 25 percent loss in rice, corn and wheat crops for every one degree Celsius increase in the average surface temperature (Deutsch et al., 2018).
As I noted in April, climate change has brought extremes to the Horn of Africa, which has been punished by heavy rain and otherwise become more arid, two conditions that help the desert locust breed. Last year, Kenya had its biggest infestation in 70 years, destroying crops (“Gaggles, Prides, Swarms and Schools,” 2020).
As a general rule, we should tolerate species living in their natural ranges at normal concentrations. When they’ve run amok, they can be reduced…carefully. As an example, the Colorado potato beetle is a major pest that exploded in numbers when we began farming potatoes. But if we kill too many, we’ll harm the wasps that eat them (Palmer, 2013). Wasps pollinate flowers just as bees do, and also kill plant-destroying pests, so their loss would be keenly felt by the ecosystem as a whole.
Insects of all kinds play varied roles in a given environment, from pollinating plants to providing a food source for reptiles and birds, which are in turn food for larger animals.
We destroy bugs – even the annoying ones – at our peril.
What we can do
“It’s grim, but it’s not too late,” says Matthew Forister, an insect ecologist at the University of Nevada (Peterson, 2021). Here are immediate steps ecologists recommend:
- Protect and regenerate tropical forest. This means allowing only selective logging.
- In temperate areas, regenerate forest on abandoned farmland and manage existing forest to protect insects. That might mean setting fires, introducing grazing livestock, and planting local trees, all of which help to regenerate depleted soils and protect it from erosion.
- Make bits of land into refuges for insects. They include roadsides, areas near powerlines, military training grounds, old mine sites, rough areas on golf courses, wind turbine sites, airports and railway embankments.
- Maintain and build freshwater ponds in cities and agricultural areas.
- Set aside farmland and enrich field borders and hedgerows. We can plant “wildflower strips” where bees nest and forage. Some enterprising states are doing this along freeways and exit ramps.
- Switch to organic farming to increase yield and insect diversity. Smaller farms, crop rotation, and limited pesticides all help (See “Hope for Healthy Farms”).
- Farmers cut pesticide use by intercropping, mechanical pest control such as tractor-mounted vacuum sweepers, and other strategies.
- In urban areas, encourage community gardens and green spaces, favor vegetation over lawns, plant vegetation on walls, build green roofs, and adapt lighting to protect insects (Samways et al., 2020).
Do you garden? You can:
- use pollinator-friendly plants
- diversify your plants
- limit pesticides
- accept some plant damage from butterfly and moth larvae
- provide clean water in bowls
- leave dead tree trunks
- support community gardens and other public green spaces (NRCS, 2021).
I’m old enough I remember holding hands, swaying in a circle in camp, singing “Where have all the flowers gone? Long time passing….”. “When will they ever learn? When will they e….ver learn?”
As scary as the cicada might appear, their appearance will be a welcome sign of a natural cycle that hasn’t gone astray. Let’s do what we can to befriend and support the insects that don’t hide from us for 17 years at a time – they need our help every day.
- Banks B. CLIMATE: Warming could open U.S. for more 'murder hornets'. CLIMATE: Warming could open U.S. for more 'murder hornets' https://www.eenews.net/stories/1063082699. Published May 8, 2020.
- Baranov V, Jourdan J, Pilotto F, Wagner R, Haase P. Complex and nonlinear climate‐driven changes in freshwater insect communities over 42 years. Society for Conservation Biology. https://conbio.onlinelibrary.wiley.com/doi/full/10.1111/cobi.13477. Published May 6, 2020.
- Deutsch CA, Tewksbury JJ, Tigchelaar M, et al. Increase in crop losses to insect pests in a warming climate. Science. https://science.sciencemag.org/content/361/6405/916. Published August 31, 2018.
- Forister ML, Fordyce JA, Nice CC, Thorne JH, Waetjen DP, Shapiro AM. Impacts of a millennium drought on butterfly faunal dynamics. Climate Change Responses. https://climatechangeresponses.biomedcentral.com/articles/10.1186/s40665-018-0039-x. Published June 5, 2018.
- Halsch CA, Shapiro AM, Fordyce JA, et al. Insects and recent climate change. PNAS. https://www.pnas.org/content/118/2/e2002543117. Published January 12, 2021.
- Harris JE, Rodenhouse NL, Holmes RT. Decline in beetle abundance and diversity in an intact temperate forest linked to climate warming. Biological Conservation. https://www.sciencedirect.com/science/article/pii/S0006320719310572. Published November 2, 2019.
- Main D. Bumblebees are going extinct in a time of 'climate chaos'. Animals. https://www.nationalgeographic.com/animals/article/bumblebees-going-extinct-climate-change-pesticides. Published February 10, 2021.
- Natural Resources Conservation Service. NRCS. https://www.nrcs.usda.gov/wps/portal/nrcs/main/national/plantsanimals/pollinate/gardeners/Accessed April 27, 2021.
- Palmer B. Pests that bug us have their own ecological importance. https://www.theguardian.com/environment/2013/may/21/insects-cockroach-bed-bugs-environment. Published May 21, 2013.
- Peterson C. Insects are vanishing at an alarming rate-but we can still save them. Animals. https://www.nationalgeographic.com/animals/article/studies-confirm-alarmiang-insect-decline?loggedin=true. Published February 10, 2021.
- Samways MJ, Barton PS, Birkhofer K, et al. Solutions for humanity on how to conserve insects. Biological Conservation. https://www.sciencedirect.com/science/article/pii/S0006320719317793?dgcid=raven_sd_aip_email. Published February 9, 2020.
- Soroye P, Newbold T, Kerr J. Climate change contributes to widespread declines among bumble bees across continents. Science. https://science.sciencemag.org/content/367/6478/685. Published February 7, 2020.
- Van Klink, R., Bowler, D. E., Gongalsky, K. B., Swengel, A. B., Gentile, A., & Chase, J. M. (2020). Meta-analysis reveals declines in terrestrial but increases in freshwater insect abundances. Science, 368(6489), 417-420. doi:10.1126/science.aax9931
- Whitt K. Billions of Brood X cicadas set to emerge in spring 2021. EarthSky. https://earthsky.org/earth/17-year-cicadas-broodx-2021. Published April 26, 2021.
- Willingham AJ. 2020 was the year of scary bugs, and 2021 will be even worse. CNN. https://www.cnn.com/2020/12/30/us/2021-murder-hornets-cicadas-scary-bugs-trnd/index.html. Published December 30, 2020.