Worldwide, more than 40 percent of insect species are near extinction and the total biomass of insects is decreasing by 2.5 percent every year, according to a survey of insect decline research published in the April issue of the journal Biological Conservation. The paper comes as the thud at the end of a grim year of “insect apocalypse” news, headlined in California by a reported 99 percent drop in the western monarch butterfly population since the 1980s.
Remember, they are an exotic species in the Western United States, and are rapidly increasing their geographic range and range of habitats. Are they outcompeting or excluding native species in the process? How would we know? We have done almost nothing to monitor changes in the assemblage of mushroom species in areas before and and after the incursion of death caps.
Further Reading
Pringle et al, “The ectomycorrhizal fungus Amanita phalloides was introduced and is expanding its range on the west coast of North America,” Molecular Biology 2009
Lockhart et al, “Simultaneous emergence of multidrug-resistant Candida auris on 3 continents confirmed by whole-genome sequencing and epidemiological analyses,” Clinical Infectious Diseases 2017
Battalani et al, “Aflatoxin B1 contamination in maize in Europe increases due to climate change,” Scientific Reports 2016
Insect Decline?
Bay Nature’s Spring 2019 magazine explores the much hyped “insect apocalypse” through the lens of local scientists, naturalists, and artists.
- What Do You Do About the Insect Apocalypse?
- Meet a Butterfly Illustrator and His Three-Year Project to Paint the Gossamer-Wings
- The Surprising Story of the Color in a Butterfly’s Wings
Butterflies seem to be among the hardest hit, and 2018 seems to have been particularly awful for them. Here’s how Art Shapiro, a distinguished professor of evolution and ecology at UC Davis who has documented butterfly populations in Northern California for 47 years, started his annual Central Valley and Sierra butterfly population survey report: “It was a terrible—perhaps even catastrophic—butterfly year at all elevations and no, we don’t know why.”
I call Shapiro to ask if he had any guesses. “Nothing that’s worth being quoted,” he says. “My last word is I don’t know what the fuck is going on but it’s scary.”
We don’t have long-term population data for the vast majority of insect species, globally or locally. Aside from the western monarchs and Shapiro’s butterfly transect, which historically has tracked no more than 159 species and subspecies, it’s hard to say if there have been insect declines in the Bay Area or not. It’s harder still to guess at what might cause them. A 2016 study led by University of Nevada–Reno biologist Matthew Forister, a former graduate student of Shapiro’s, correlated Northern California lowland butterfly declinesbeginning in the late 1990s with the increased use of neonicotinoid pesticides. But many of the places showing declines now aren’t near agricultural areas. The monarchs, which migrate through Central Valley farms, also underwent a precipitous decline at the end of the ‘90s—but in 2018 they might have just been victims of a bad weather year, the circumstance of a population closer to the edge than we’d realized that finally was pushed over it by bad luck. “Most things, in my experience, are more complex than one perhaps would like them to be,” Shapiro said.
If this news feels a bit numbing, it’s nonetheless a story you can help write a better ending to. The natural world needs witnesses. We know about the decline of the monarch only because citizen scientists have been documenting monarch populations for decades. And there are innumerable ways to witness and observe, from chronicling monarchs’ decline to painting a butterfly family to simply taking time to learn about and appreciate the diversity and wonder that remain—like the remarkable nanostructures that create color in a butterfly’s wings.
Caveats to the Apocalypse
This might be the year of the “insect apocalypse,” but thanks to a group of determined scientists, naturalists, and citizen allies, many of the Bay Area butterfly stories these days are more optimistic in the face of the international headlines. “Thinking globally I get really depressed,” says ecologist Stuart Weiss. “Acting locally, I get a modicum of hope.”
Weiss and company have moved federally endangered Mission blue butterflies to Milagra Ridge and Twin Peaks to re-establish and increase the populations there. They have restored threatened Bay checkerspot butterflies on San Bruno Mountain. Coastal green hairstreaks are spreading across San Francisco due to the efforts of citizen scientists and the nonprofit conservation group Nature in the City.
Likely the most common butterfly in California is the variable checkerspot. It flies almost everywhere except in San Francisco, where development caused it to become extirpated by the 1980s, with the exception of a small population at Laguna Honda. Starting two years ago Presidio Trust ecologists led by Jonathan Young trucked about 1,500 checkerspot caterpillars in from San Bruno Mountain. This spring Young and Liam O’Brien counted swarms of newly hatched checkerspot caterpillars, making it native again in San Francisco. They don’t plan to move any caterpillars
this year.
“I had a discussion with somebody once,” Weiss says. “I made a reference about working in my Bay Area bubble. They said, ‘It’s not a bubble. It’s a beacon.’”
Ways to help
• Volunteer or partner with the Green Hairstreak and Tigers on Market Street butterfly conservation projects by San Francisco nonprofit Nature in the City.
• The Great Sunflower Project, the nation’s largest citizen science pollinator project, was started by San Francisco State ecologist Gretchen LeBuhn and needs your observations.
• The Pollinator Posse tries to restore insect-friendly landscapes to urban areas and backyard gardens throughout the East Bay, including a new project to help the pipevine swallowtail butterfly.
• Lawns are generally terrible for insect abundance and diversity. Residents of several Bay Area cities who replace their lawns can get up to a $4-per-square-foot rebate through the Bay Area Water Supply and Conservation Agency. Find out if you’re eligible or apply here.
• One of the chief drivers of insect declines is agriculture. Support a healthier food system by looking for food grown without pesticides, especially neonicotinoids. Learn more about neonicotinoid pesticides and bees from the Xerces Society.
