Counting Butterflies

Photograph by Pete Oxford / Nature PL


Where have all the insects gone? The Frontline dives into the great insect decline—and how a group of scientists in Ecuador is revolutionizing how we may solve it.

On the western edge of the Amazon Rainforest, pressed against the Andes, Yasuní National Park is thick with life. It is considered one of the most biodiverse places on this planet: there are more amphibians, mammals, birds, and plants here than almost anywhere else in the world. But, like so many conservation hotspots, danger is pressing in on all sides. There is the looming threat of climate change: warmer temperatures and changing seasonal patterns threatening the delicate, intricate ecosystem. And then there are acute threats: deforestation and development, oil drilling within park boundaries, illegal logging


Local scientists and activists have long emphasized the global significance of protecting Yasuní. The Ecuadorian government—and the world at large—must know what is at stake if the park is further opened up to development, what we may lose. But, in measuring the park’s biodiversity, there’s a missing piece: insects. In Yasuní, insects are wildly diverse and in grave danger, but that’s about all we know of them. 


While Yasuní’s big, charismatic animals like jaguars and macaws have been well-cataloged, we still don’t know how many insects are in the park—or the complete picture of their diversity. In a study published in February in the journal Insect Conservation and Diversity, a team of entomologists, ecologists, and Yasuní park rangers try to chip away at those questions. 


After all, how can we know what we’re losing if we don’t even know what we have?

In field guides designed by scientists, rangers can see both the dorsal and ventral sides of the butterfly in order to identify them. Butterflies, clockwise starting with the top left: Heliopetes alana, Myscelus nobilis, Phocides sp., Phaeras coeleste. (Photographs courtesy of María Checa)

We know shockingly little about most insects. We’re still discovering new organs in some species and trying to uncode the mysteries of flight in others. Scientists suspect that insects make up around 80% of all animal species, but we still haven’t named most of them. We’ve described over 1 million species of insects, but scientists estimate that there are as many as 10 million species. What we do know is that they’re declining—and fast. Agriculture, insecticides, deforestation, and climate change are prompting a global insect decline. One review estimates that over 40% of insects are at risk of extinction in the coming decades. 


The trouble is, without knowing how many insects there are, it’s hard to get good numbers on the scale of the decline. Entire species could disappear without us ever recognizing them. This is dangerous for us and the rest of the ecosystem: insects are pollinators and nutrient cyclers, ensuring plants can reproduce and ushering the flow between death and new life. All the animals that rely on insects for food, too, are at risk. Because insects are at the base of the food chain, that’s pretty much everyone: frogs, birds, lizards, mammals like armadillos and bats, and any creature that eats insect-eaters. 


“Sometimes when we speak about biodiversity, it’s an abstract concept,” said María Checa, a butterfly scientist from Ecuador who led the Yasuní-focused study published in February. “With insects, the results are very striking. The consequences of insect extinctions can be very dangerous for our own survival.”


Without pollinators, we would quickly be in a global food crisis. Insect-pollinated crops make up over a third of what we eat, including many fruits and spices. Many scientists also suspect that insects could be a source of new medicines, borrowing their natural defenses to treat human diseases—opportunities that would be lost if we don’t stop insects from disappearing. 


In the face of these ever-increasing threats, science has a data problem. Most biodiversity research happens in temperate regions in the Global North, but most of the insect diversity is in the tropics. The best data on the butterfly decline, for example, come from European countries like the U.K., which has about 60 butterfly species. In comparison, Ecuador has at least 4,000, according to Checa. Studies in the tropics, historically, have been short and sporadic. Scientists will come down from the U.S. or Europe and spend a few months in the field, then return back to a lab at home to analyze the data. This kind of patchy research doesn’t make for a broad, detailed understanding of how many and which kinds of insects are fluttering around Yasuní, nor which ones are in danger. For that kind of data, you need to have long-term monitoring studies, ones that run over decades.


A few years ago, Checa was talking about this very problem with her adviser, Keith Willmott. Checa and Willmott are both butterfly scientists—she from Ecuador, he from the U.K.—who are working to understand Yasuní’s butterfly community. 


Checa and her team came up with a new approach to monitoring butterfly populations in Yasuní National Park, laid out in their February study: training park rangers. After attending workshops on identification, park rangers set up and checked baits loaded with rotting carrion, allocating five full working days every two months to the job. After three years of data collection, the scientific team released their findings: the rangers were 85% accurate with their identifications. 

“I believe that conservation is only possible when we involve local people.”

María Checa
Study's Lead Author

This finding was critical. Using citizen science—or, in this case, training people as “parabiologists”—is a growing trend in conservation research, but some remain skeptical that it can provide good data. The high accuracy of the rangers’ identification (especially in a place as diverse as Yasuní) meant that scientists could use the data to determine key parameters like biodiversity and species richness. 


The program began with lessons on ecological theory, then jumped straight into practical training. In 2014, the monitoring began. Scientists accompanied rangers at first as they learned to identify butterflies, recording each new visitor by taking a picture, giving it a number, and then releasing it back into the wild. Later, Checa and her colleagues were available over WhatsApp for consultations. 


During each week of monitoring, rangers would set the baits in the morning, checking them the next day. Amid the wide-leaved underbrush, below the chirping, rustling canopy, one ranger must carefully remove the butterfly from the trap, then hold it in their palm, fingers laid flat. As the butterfly slowly opens and closes its wings, the other rangers consult their field guides, trying to place the precise pattern of its wings. Some species are easy to identify—the turquoise and lime green of Arcas imperialis, tendrils furling from its hind wings like pieces of burning paper. Others are hard to distinguish—is that electric flash of blue and brown underside Calycopis demonassa or Calycopis atnius? The hint, often, lies in the details: a tiny red design on the edge of one wing. 


The rangers quickly got the hang of it, doing especially well with common species. Knowing now that park rangers can correctly identify the butterflies, the team of scientists feel hopeful about the long-term monitoring system. It cost almost nothing as the Ministry of Environment, Water, and Ecological Transition covers the rangers’ wages and lodging. Because the system doesn’t rely on continual funding, it’s also more likely to be sustainable. 

Butterflies, clockwise starting with the top left: Arawacus separata, Arcas imperialis, Cyanophrys sp, Chalybs hassan. (Photos courtesy of María Checa)

“Long-term monitoring studies are very expensive. There is no institution that can fund full-time and indefinitely a biodiversity monitoring program like this,” Sofía Nogales, one of the study’s co-authors, said in Spanish via email. “For that reason, it was essential to join forces with institutions and people that were already established and working to manage and conserve biodiversity.”


And, critically for Checa, this project takes the mystery away from science and puts the knowledge back in the hands of the community. She’s always focused her work on being a bridge between the lab and the real world: including people in science and tailoring her research to their conservation questions. She attributes this focus to growing up and living in Ecuador, one of the most biodiverse countries on Earth—and one whose government is still focused on extracting natural resources without consulting local people. 


“When you do an analysis looking at where the biodiversity is concentrated, it’s also where poverty is concentrated,” Checa said. 


But when governments make conservation decisions, they often exclude local groups. There are multiple tribes inside Yasuní National Park, for example, two of which are uncontacted: the Tagaeri and Taromenane. The Ministry of Environment designed the protected area, in part, to protect the tribes, but officials didn’t take into account that the tribes are nomadic. They move throughout the park, often over oil blocks, to hunt, fish, and gather plants. Over the years, oil drilling has moved closer and closer to the buffer zone—called the Intangible Zone—where the Tagaeri and Taromenane live. 


The tribes now face a real threat of extinction, Checa said, and many of the threats to their livelihood are the same ones that threaten the region’s wider biodiversity: the building of roads, the opening of more oil wells, the heating of the planet. “I believe that conservation is only possible when we involve local people,” Checa said. “Those who have power are those who can make decisions about our world. It should not be like that anymore if we really want to make changes.”


Already, though, the team is seeing the benefits inclusion has on the community. The park rangers—many of whom belong to neighboring Indigenous communities, Nogales said—feel more empowered to understand and protect their forests. Checa said that this impact is especially strong on the women, who have often stepped up to be leaders in the project. Promoting gender equality is paramount in rural Ecuador, Checa said, where gender discrimination is greater than in cities


“In rural areas, it’s really bad. They are usually married by 14 years old, they don’t go to school, they don’t have access to knowledge, they do what their husbands tell them to do,” Checa said. “It’s important for us that these women have the same opportunities as men.” 

“The consequences of insect extinctions can be very dangerous for our own survival.”

María Checa
Study's Lead Author

This study isn’t designed to measure all of biodiversity or every insect impacted by the global decline. The rangers are tracking only butterflies, leaving out all the beetles, ants, leafhoppers, treehoppers, flies, bees, mantises, and dragonflies. But this is how science works: no one can ever set out to get the complete picture, measuring all of life on Earth. You have to take it piece by piece, filling in your corner and trusting that there are other scientists—and citizens—working on the rest. 


Though we may never understand all of the natural world, certain bioindicators—like butterflies—can help us screen the health of an ecosystem. Butterflies are particularly good at this job because they are easy to sample and (as far as insects go) relatively well-studied. They’re ectothermic (their internal temperature depends on the environment) and so very sensitive to slight changes in their natural environment, like those in temperature, humidity, light, and vegetation, Nogales said. Their life cycles are also short, Checa pointed out, often only two months long. 


“If it faces a challenge that decreases survival, you have a decrease in the population in the next generation,” Checa said. “That means in one year, you have five generations affected by any changes in the environment.”


If butterflies are declining, you know that the rest of the ecosystem is probably affected—or will be soon.


Already, Checa said, there are species she found while doing her bachelor’s thesis 20 years ago that the team of scientists and rangers haven’t found again. She sampled for only 16 months in 2001, and they’ve already been sampling for years. Is it a local extinction? A shift in range? The only way to tell would be to expand the monitoring program to other areas in the park and, then, other protected areas in Ecuador. Already, the program has expanded from three rangers to 13 rangers, and the rangers want to take the research further. 

Butterflies, clockwise starting with the top left: Ostrinotes tympania, Paiwarria antinous, Paraspiculatus orobia, Paraspiculatus emma. (Photographs courtesy of María Checa)

“When we started the project, [the park rangers] complained that scientists came, got their help, then completely forgot about them,” Checa said. “They were not included in the manuscript at all.”


Checa and her colleagues have since offered workshops on statistical analysis, and the original three park rangers are listed as co-authors on Checa’s study. Some of the park rangers are even working on their own manuscript right now, analyzing the data they’ve collected.


Often, the smallest species are the easiest to overlook. In the short term, it may seem more worth it to build roads and cut down trees than to ensure the future of a butterfly. Our common conception of insects is, largely, as pests: mosquitoes and fleas, bearers of disease. But Checa pointed out that the decline in insect diversity can allow for these dangerous and annoying species to flourish as they fill the roles left behind by disappeared pollinators.


Maybe by understanding insects better, by getting eye level, and holding them in outstretched hands, we can begin to understand their place in our world. By uncovering the most basic, elusive facts—how many there are, how fast they’re vanishing—we can understand how truly inextricable their survival is from our own. While we search for answers, we can—in the ways we already know how—protect.

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