Are Entomologists as Endangered as the Insects They Study?

All life depends on insects. As many species decline and others—including disease carriers—relocate, the entomologists who study them are becoming endangered.

  • By Erica Goode
  • Conservation
  • Mar 28, 2024

At Maryland’s Patuxent Research Refuge, insect taxonomist Sam Droege scouts for bees amid native vegetation. (Photo by Amanda Andrade-Rhoades.)

SEND AN EMAIL to Sam Droege on a Monday, and the automated response will be, “Mondays are sacred bee identification day,” accompanied by a suggestion to try again later in the week.

Droege, a wildlife biologist with the U.S. Geological Survey (USGS), has been a self-described “bee head” for more than two decades. In a converted garage on 30 acres of federal land inside the Patuxent Research Refuge in Maryland, he leads the USGS Native Bee Inventory and Monitoring Lab, which develops surveys of native bees and tools for identifying them, and holds a database of more than 750,000 bee specimens. Inside the lab, hundreds of pizza boxes filled with dead bees are stacked high on bookshelves, file cabinets and any other available surfaces.

Most days, Droege can be found there, working with other scientists and volunteers, washing and drying bee specimens or pinning and labeling the insects with the times, dates and places they were found. But on Mondays he stays home to identify bees—examining mandibles, eyes, thoraxes, antennae and other bee body parts under a microscope. On one recent Monday, he worked his way through 10 pizza boxes, each containing about 75 bees. “You don’t really want them tightly packed,” he says. “That has consequences. You’re more likely to snap off a head or an abdomen.”

Droege’s work is important not just to people passionate about bees. Scientists who identify, classify and study insects and the ecosystems they inhabit are essential to preventing the loss of the insect species that humans and all other living things depend on. They are also of critical importance for detecting and controlling diseases carried by ticks, mosquitoes and other invertebrates that can bring humans and other animals harm.

This expertise is increasingly needed at a time when a multitude of threats—from climate change and habitat loss to pesticides and invasive species—are driving precipitous declines in some insect populations, shifting the ranges of others and fostering the outbreak of diseases such as West Nile and Dengue fever. In the United States, cases of such vector-borne diseases—transmitted to humans by blood-feeding arthropods—have doubled over the past 20 years, according to the Centers for Disease Control and Prevention (CDC).

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An image of Sam Droege sitting at his desk.

Faced with hundreds of pizza boxes holding more than 750,000 bee specimens, Droege, who leads the USGS native bee lab, has more than enough work to last a lifetime.

Losing vital expertise

But Droege and other insect taxonomists like him are in short supply, especially when compared to the escalating need and the number of species still unknown to science. By conservative estimate, between 5.5 million and 7 million insect species inhabit the planet, according to a 2018 review in the Annual Review of Entomology, with only some 1 million of those identified. In contrast, less than a quarter of the 6,729 members of the Entomological Society of America (ESA)—down from 7,189 in 2020—belong to its “systematics, evolution and biodiversity” section (one of four interest-oriented divisions), and only a portion of those scientists are practicing taxonomists.

Dwindling funds have fueled the taxonomist shortage. Over the past few decades, research funders like the National Science Foundation (NSF) and the National Institutes of Health (NIH) have shifted their priorities from “old-fashioned” descriptive sciences like taxonomy to cutting-edge fields like molecular biology, with researchers and students adjusting their career trajectories accordingly. And as an older generation of classically trained natural historians approaches retirement, their slots at universities are remaining unfilled.

“We’re rapidly losing the expertise we need in quite a diversity of areas,” says Lynn Kimsey, professor of entomology and director of the Bohart Museum of Entomology at the University of California, Davis. “The driving force in universities is funding, and almost all the funding out of agencies like NSF and NIH is directed at DNA.”

Her own department offers one example. “At one point we had three taxonomists: one working on ants, one working on spiders and one working on stinging wasps,” she says. “Within five years, two of the three will be gone, and they won’t be replaced. And I’m seeing that at universities across the country.”

In Europe, a 2022 analysis across 27 countries, released by the European Commission in response to reports of insect population drops, concluded that “in parallel with the decline of insect species, there is also a worrying decline in insect taxonomic expertise, which hinders conservation efforts.” The vast majority of taxonomists, the analysis found, were over age 40, with only 6 percent at an early career stage. There is also a lack of permanent jobs for taxonomists, even in museums, which tend to focus on “putatively more ‘modern’ types of research,” notes the report. A key factor in this erosion of taxonomy expertise was lack of funding.

In a 2023 perspective published in Diversity—which called for more funding for permanent taxonomy positions and bemoaned the “low esteem” in which the once-respected field was held—a group of researchers from both sides of the Atlantic described the problem more bluntly, titling their article, “The Silent Extinction of Species and Taxonomists.”

For medical entomology, things are slightly better. Since the 2016 Zika outbreak, when CDC was so short of entomologists it went begging to universities to loan their experts out, the agency has invested substantial funds in training for entomologists and vector-control specialists. Yet even with more federal support, the number of entomologists who can accurately identify disease vectors pales in comparison with demand for their expertise.

“If there’s a new or even an existing vector-borne disease outbreak, someone needs to be able to go out there and say, ‘This is the shoobadoo bug, this is their habitat, this is how the weather impacts their behavior,” says Jerome Goddard, extension professor of medical and veterinary entomology at Mississippi State University. “I don’t see that level, that breadth of knowledge.”

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An image of a box containing bee samples.

Before the specimens can be examined under a microscope, they first must be washed, dried, pinned and labeled with the times, dates and locations where they were collected.

Why we need insects

How important are insects? A report by two researchers who studied apple farming in China’s Sichuan province offers a telling example. Decades of pesticide spraying and habitat loss devastated the pollinator population in the province’s Maoxian county, forcing apple farmers there to pollinate their trees by hand. But the cost of hand pollination became unsustainable, the scientists noted in the 2012 study. “Apples are no longer the number one crop in the valley,” they wrote.

Scientists, who have worried about insect declines for more than a decade, say that determining with certainty how much populations have fallen is difficult. A growing number of studies have documented significant drops in insect abundance or biomass. These declines, a 2021 review in the Proceedings of the National Academy of Sciences found, vary with type of insect, location and other factors, but often come in at 1 to 2 percent a year, with some regions losing 10 percent or more of their insects over the course of a decade.

The studies, though, have been carried out primarily in the United States and Western Europe, with data lacking in many other parts of the world. Complicating matters, insect populations go through natural boom-and-bust cycles. And as Droege points out, scientists report declines but are less likely to publish findings if their studies find no change.

Still, few entomologists question that there’s ample reason for concern: One has only to think of places that were once grassland or forest or desert and now are not. Pick a parking lot, a housing development, a shopping center, a whole city, says Droege. “At some point, if you go back far enough, that was great natural habitat.”

Yet it can be hard to draw public attention to an insect crisis. Imperiled elephants are an easy sell; the endangered pygmy hog-sucking louse, not so much. “The big problem in trying to get people to understand the importance of insect decline is: Why should they care? Well, you have to care,” says May Berenbaum, former ESA president and head of the entomology department at the University of Illinois Urbana-Champaign. “It’s impossible to live an insect-free life on this planet.”

Berenbaum ticks off a list of insects that provide services essential for humans’ quality of life. She begins with caterpillars and other insects birds feed on, because “people like birds,” she says. “Most have no idea that 96 percent of birds wouldn’t be here without insects,” adding that it takes 6,000 to 9,000 insects to feed a single clutch of four to six chickadee offspring.

Pollinators, not only bees and butterflies but also moths and many other kinds of insects, are just as essential. “If you lose them, then you lose a lot of the food supply,” says Berenbaum. Without dung beetles and other recyclers, she says, plant and animal waste would pile up. And then there are the insects that help keep other, harmful insects—from mosquitoes and other disease vectors to crop pests such as armyworms—in check: the dragonflies, ladybugs, green lacewings, ground beetles, parasitic wasps. If they disappear, Berenbaum says, “we could be overrun by pest species.”

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An image of a rusty patched bumble bee.

A rusty patched bumble bee (Bombus affinis) specimen collected in Wisconsin. Once common throughout the eastern United States, B. affinis has declined dramatically and was listed as endangered under the U.S. Endangered Species Act in 2017. Droege and his colleagues create many such macro portraits of the lab’s specimens, both bees and beyond. The photos’ popularity on social media has won converts to the cause of insect conservation. See six more examples in the slideshow below.

Hope from a new generation

The problem is that with so many insects unidentified, you might not know what ecological niche a species fills until it’s gone. Droege illustrates this with the analogy of a brick house. “I could knock out quite a few bricks, and it would still be a brick house,” he says. “But at some point, I knock out the wrong brick, and a section would collapse. If we don’t know the names, we won’t know what role it plays.”

Meanwhile, climate change, habitat loss and other human threats are not just knocking out species but pushing them into new areas, some carrying diseases. And again, identification and knowledge about an insect’s ecology are key.

Different mosquito species, for example, with different biologies require different control tactics, says Roxanne Connelly, chief entomologist for CDC’s Division of Vector-Borne Diseases. “We have so many mosquitoes that look the same,” she says. “It’s very hard to tell them apart. And it’s important to tell them apart.”

Given the vastly unequal ratio of scientists to insects, the temptation might be to despair. But there are hints that, at least in some quarters, the calls to action have been heard. “People are sort of awakening to the realization that insect decline is not irrelevant to their existence,” Berenbaum says.

CDC, for example, has established Centers of Excellence at universities around the country and poured more than $100 million into disease-vector research as well as training medical entomologists and vector-control specialists to serve at state and local levels. It has also partnered with ESA on a fellowship and internship program for university undergraduates and recent graduates called Public Health Entomology for All, aimed at increasing workforce diversity. “We realized, when you look at the field of public health entomologists, a lot of them are old white men like me,” says Ben Beard, deputy director of CDC’s vector-borne disease division.

Outside universities, community science is picking up some of the slack. Amateur insect experts flock to digital tools like iNaturalist, their efforts amplifying the hunt for new species to identify. And labs like Droege’s attract a stream of volunteers, giving him some hope for the future. Many of the new enthusiasts remind him of himself at a younger age, Droege says. They spend a lot of time with books; are obsessed with collecting insects; love birds, plants and nature generally; and are at home when surrounded by glass cases of dead invertebrates. “Looking at bugs and being in a museum is not something analogous to being a quarterback,” he says. “I think a lot of them are finding their people.”

Roshan Vignarajah, a volunteer at the bee lab, is a case in point. At age 13, he is, Droege says, “one of the best firefly experts in the nation.” Recently, Vignarajah discovered a new firefly species and hopes to publish a paper on firefly range expansion next spring. “I love fireflies,” he says, adding that few scientists specialize in the insects, “which means I can make a lot of difference in the world of firefly taxonomy.”

Is he likely to pursue entomology as a career? “It’s something I’ve always been interested in,” Vignarajah says. “There’s no reason I wouldn’t be interested in it in 20 years.”

Erica Goode is a science writer and editor who lives in New York City. Read more about her.

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