Scientists have no idea if most of America’s bugs are dying out

Study finds 88% of North American insects haven’t been assessed for extinction risk

For nearly nine out of ten insect and arachnid species in North America, science has no answer to a basic question: are they in danger? Many have no extinction risk assessment and little population data on record. A new study finds that the conservation status of 88.5% of described insect and arachnid species on the continent is entirely unknown, and that species with unknown status are the least likely to ever receive legal protection.

That finding comes from researchers at the University of Massachusetts Amherst, where researchers reviewed conservation records for more than 46,000 North American insect and arachnid species and cross-referenced them against state and federal endangered species laws. Published in the Proceedings of the National Academy of Sciences, the study by Wes Walsh and Laura Figueroa offers a comprehensive quantitative assessment of U.S. insect and arachnid conservation, outlining where the gaps are and what’s driving them.

Insects and arachnids account for roughly 73% of all described animal species on Earth. They pollinate crops, control pest populations, cycle nutrients through soil, and rank among the most sensitive indicators of air and water quality available to science. Researchers have estimated their combined ecological services at roughly $57 billion annually to the U.S. economy alone.

A Data Crisis at the Heart of Insect and Arachnid Conservation

Walsh and Figueroa used NatureServe, the primary biodiversity database that U.S. government agencies rely on to make conservation decisions. Less than half of all described insect and arachnid species in North America even have an entry in the database. Of those that do, more than 75% have never been evaluated for extinction risk.

Every described bird species on Earth has been assessed for extinction risk by the International Union for the Conservation of Nature. For insects and arachnids, that figure sits at roughly 1%.

The consequences are legal, not just scientific. Species without a formal assessment are far less likely to receive protection under the Endangered Species Act or any state-level equivalent. Because unassessed species are less likely to receive protection, the authors argue that a lack of evaluation can leave species effectively outside conservation policy altogether. Even among species that have been assessed, basic population trend data are often missing, meaning researchers may suspect a species is struggling but can’t build the legal argument to protect it. Without a concerted push to study a far wider range of insects and arachnids, the authors warn, many species may disappear before science ever gets around to looking.

What the Numbers Reveal About Endangered Insects in America

Among insects and arachnids confirmed as at-risk across their full range, just 5.3% are protected by any federal or state law. Under the federal Endangered Species Act, only 2.5% of at-risk insects and arachnids carry a listing. For at-risk U.S. bird species, that number is 27.7%.

As of 2024, the ESA covered 108 insect and arachnid species total. Butterflies and moths account for the largest share. Arachnids are nearly invisible: only 11 arachnid species hold federal protection, and nine of those come from a single cave system in central Texas.

State laws don’t close the gap. Only 26 states clearly include insects in their legal definition of wildlife. Just five states protect even a single arachnid species. Across every state and federal law in the country combined, 94.7% of insects and arachnids known to be at risk of extinction are protected by nothing.

Why Some Bugs Get Protected and Others Don’t

Even within the narrow slice of species that do receive legal protection, there is a clear preference for familiar, visually appealing bugs. Dragonflies, damselflies, butterflies, and moths dominate both state and federal protection lists. Stoneflies and caddisflies, two groups scientists monitor extensively as water quality indicators, barely register despite being among the most imperiled insect orders on record.

More than 45% of assessed stonefly and caddisfly species in the U.S. are considered at-risk across their full range. Roughly 1% or fewer are protected by any law. For dragonflies, the federally protected share of at-risk species is 26.8%. For butterflies and moths, it is 11.6%. Walsh and Figueroa suggest this pattern likely reflects human bias toward large, colorful, day-flying species that people are likely to notice and appreciate, though they acknowledge that differences in monitoring and inherent risk among species groups may also be contributing factors. A stonefly clinging to a streamside rock is an irreplaceable indicator of clean water. To most people, it is also just another bug.

Arachnids face additional barriers. Many people find spiders and their relatives unsettling, which undercuts public support for their conservation. Some of the most imperiled groups, including pseudoscorpions and harvestmen, are small, dull-colored cave dwellers that most Americans will never encounter. To the extent those groups have been assessed at all, they rank among the most at-risk invertebrates on the continent.

Economic Forces Shaping Insect Conservation Policy

Walsh and Figueroa tested a wide range of possible explanations for why some states protect insects and others don’t: number of at-risk species, ecosystem diversity, state wealth, and the presence of major research universities. None of these factors emerged as significant predictors in the models.

What did emerge was a correlation with money. States where mining, quarrying, oil, and gas extraction make up a larger share of the economy were less likely to have a functioning endangered species law, and if they did, less likely to include insects and arachnids as eligible for protection. The authors note that extractive industries have a documented history of opposing federal species protections, and suggest similar dynamics may be playing out at the state level, though the study measures correlation rather than direct cause. Notably, the regions with the fewest protections, the South and the West, are also home to the country’s greatest insect and arachnid diversity and its highest concentrations of at-risk pollinators.

Where protections do exist, public attitude was the deciding factor. States with smaller extractive industry sectors and higher rates of eco-centric values among residents tended to protect more species overall.

Without broader assessment and monitoring, the authors argue, many species could disappear before their conservation status is ever understood. Most of America’s insects and arachnids have never had their conservation status assessed. Among those known to be at risk, almost none are protected.