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| Exemplary reflected micro-Doppler spectrograms from wing flapping of five different pollinating insect species, computed from the unfiltered radar signals to illustrate the full micro-Doppler structure, including low-frequency components. Credit: PNAS Nexus (2026). DOI: 10.1093/pnasnexus/pgag096 |
Bee more specific: New radar tech could improve identification and tracking of key pollinators
The Pollinator Reckoning
A new millimeter-wave radar can identify a bee by the spectrum of its wings vibrating. It arrives at a moment when American beekeepers have just lost more than 1.7 million colonies, the EU has reclassified one in ten of its wild bees as threatened, and the agricultural economy that depends on these insects is being forced to confront just how fragile its foundations have become.
Bottom Line Up Front
A Bee, Resolved by Radar
On a quiet field at Trinity College Dublin, a bumblebee crawls into a small plastic cylinder placed atop a millimeter-wave antenna. A few seconds later it is released, unharmed. In the time it took for the insect to flick its wings, a software model has compared more than seventy harmonic, spectral, and temporal features of the radar return against a reference library and decided, with high confidence, that this was Bombus terrestris—not a wasp, not a honeybee, not a hoverfly that happens to look superficially similar.
The technique, reported in PNAS Nexus by Linta Antony, Adam Narbudowicz, Ian Donohue, Jane Stout, and colleagues at Trinity College Dublin and the Technical University of Denmark, exploits the same physical phenomenon that lets a phased-array radar separate a helicopter from an airplane: micro-Doppler modulation. Insect wings produce distinctive, species-specific frequency signatures when illuminated by short-wavelength electromagnetic energy. Trained on a hierarchical machine-learning model, the system can resolve closely related species that are nearly impossible to distinguish visually—or by the lethal pinning, drying, and microscopy that has been the entomologist's standard since the 18th century.5
"Crucially, the approach means we can accurately identify different species, even telling apart very closely related insects," Trinity ecology professor Ian Donohue told Phys.org. "And unlike large-scale monitoring systems, this technique can also operate cheaply and effectively over a small spatial range, making it particularly suited to studying insect activity directly in and around flowers."9
The hardware bill of materials matters here. Millimeter-wave radar at 60 to 90 gigahertz is no longer exotic instrumentation; it is the same frequency band being deployed for 5G fixed-wireless backhaul and, soon, 6G. Antony's team explicitly designed the sensor to be compatible with that infrastructure, raising the prospect that pollinator monitoring could eventually be folded into the same networked sensors that move cellular data, with no new towers required. For an ecological discipline that has long been forced to choose between expensive trapping campaigns and statistically thin volunteer counts, that is a structural change in what is measurable.
Why Identification, Not Counting, Is the Question
The standard public framing of pollinator decline still revolves around honeybees, but most working ecologists consider that framing close to a category error. Apis mellifera, the Western honeybee, is a managed agricultural animal—essentially livestock—and represents less than one percent of the world's roughly 20,000 bee species. The IUCN noted in October 2025 that managed honeybees "cannot easily replace" wild bees because they are selected for honey production and a few specific crops, while the broader pollination services that flowering plants depend on are delivered by a vast portfolio of solitary bees, bumblebees, hoverflies, beetles, butterflies, and moths.3
That portfolio is what the new radar can finally see. Counting insect visitors to a flower has always been possible; knowing whether those visitors actually transferred pollen, and whether the species mix matches what the crop requires, has not. Coffee, almond, blueberry, apple, watermelon, and squash all have different pollinator preferences. A field full of generalist visitors may look healthy in a count and still be failing as an agricultural system.
The 2025 Collapse, and What Caused It
The urgency of the diagnostic problem became unavoidable in early 2025. As commercial beekeepers staged their colonies for the California almond bloom—an annual migration that requires roughly 70 percent of all U.S. honeybee colonies converging on a single crop—they began reporting catastrophic losses. The Auburn University–led U.S. Beekeeping Survey eventually documented that annual colony losses across the 2024–2025 season averaged 55.6 percent, the highest figure since the survey began in 2010. State-level losses ranged from 34.3 percent to 90.5 percent.10 A parallel survey by Project Apis m. and the American Beekeeping Federation, capturing data from operations managing roughly 72 percent of U.S. commercial colonies, put commercial losses between June 2024 and February 2025 at 62 percent—approximately 1.7 million hives and an estimated $600 million in lost revenue.1
In June 2025, the USDA's Agricultural Research Service announced its forensic findings. The Bee Research Laboratory at Beltsville, Maryland, had screened bees and mites from six major affected operations for thirteen known pathogens and parasites. Two viruses—deformed wing virus (variants A and B) and acute bee paralysis virus—were present at high levels in all collapsing colonies. Crucially, virtually every Varroa destructor mite collected carried genetic markers for resistance to amitraz, the dominant miticide in commercial American beekeeping for more than a decade.2 The peer-reviewed analysis was published in PLOS Pathogens in February 2026.11
The implication is uncomfortable for the industry: the principal chemical defense against the principal vector of the principal viruses has stopped working. Replacement chemistries exist but are not yet at scale, and the breeding of mite-resistant honeybee stock remains a multi-year project.
Wild Bees: A Slower, Larger Crisis
The 2025 commercial crash is, in a sense, the loud version of the story. The quieter version, unfolding over decades, concerns wild and unmanaged pollinators—and the data on these are now sharper than ever. The IUCN's October 2025 update of its European Red List of Bees evaluated 1,928 species and classified 172 of them (approximately 10 percent) as threatened with extinction, a figure that has more than doubled since 2014. More than 20 percent of European bumblebee and cellophane bee species are now at risk. The mining bee Simpanurgus phyllopodus, the only member of its genus on the continent, is now Critically Endangered. The Madeiran large white butterfly (Pieris wollastoni) has been declared Extinct.3
The IUCN report identifies four main drivers, in roughly the order entomologists have long predicted: agricultural intensification (especially the loss of flower-rich meadows), pesticide exposure, nitrogen deposition from fertilizer runoff, and climate-driven changes in the timing and geography of bloom. Cold-adapted species such as alpine bumblebees are squeezed upslope; carpenter bees and other warm-adapted generalists are expanding. The net biodiversity result is loss.
In the United States, Ireland's National Biodiversity Data Centre has documented a 3.5 percent annual decline in bumblebee populations since 2012, and the U.S. Fish and Wildlife Service has reported eastern migratory monarch butterfly declines in excess of 80 percent since the 1980s.69
What the Loss Costs in Calories and Cash
For a long time the economic case for pollinators rested on a single often-cited figure: that animal pollination supports approximately 35 percent of global crop production by volume and 87 of the world's 115 leading food crops, contributing on the order of $175 billion annually in ecosystem services.12 A 2025 review in Ecological Economics using updated bioeconomic data revised the implied cost of a hypothetical global pollinator collapse upward to roughly $729 billion in welfare loss—about 0.9 percent of global GDP—along with an 8 percent reduction in global Vitamin A availability.13 A separate Nature Communications modeling study in late 2025 found that a hypothetical European wild pollinator collapse by 2030 would cut EU crop yields by 8 percent and reduce global welfare by approximately €34 billion per year.14
Until recently, those numbers were aggregate and abstract. That changed on 6 May 2026, when a team led by Thomas Timberlake of the University of Bristol published in Nature the first study to trace the full chain from individual wild pollinators to individual human nutritional outcomes. Working in ten smallholder farming villages in Nepal, the researchers tracked crop–pollinator interactions, family income, and individual diets simultaneously. They found that insect pollinators were directly responsible for 44 percent of farming income and contributed more than 20 percent of household intake of vitamin A, folate, and vitamin E. Roughly a quarter of the global population is currently affected by micronutrient deficiency—"hidden hunger"—and the study is the strongest evidence yet that pollinator decline is not merely an environmental abstraction but a public-health vector for the world's poorest two billion people.4
"When pollinators decline, families risk poorer nutrition, leading to higher vulnerability to illness and infections, and deeper cycles of poverty and poor health," the University of Bristol's announcement of the study noted. The findings are now informing a National Pollinator Strategy under development in Nepal.15
The Regulatory and Legal Front
The legal architecture around pollinator protection is fragmenting along familiar transatlantic lines, with the European Union pushing toward stricter chemistry rules and the United States lagging at the federal level while individual states act.
Neonicotinoids
The European Union banned outdoor uses of imidacloprid, clothianidin, and thiamethoxam—the three most heavily implicated neonicotinoid insecticides—in 2018, and announced in 2024 that it would prohibit imports of products containing trace residues of those compounds beginning in 2026.16 Member states have continued to grant emergency exemptions; in 2023 alone, more than 200 such exemptions were issued, roughly half involving neonicotinoids. EU regulators are also reviewing two remaining neonicotinoids, acetamiprid and thiacloprid, in 2025.8
In the United States, the Environmental Protection Agency's registration review of the five major neonicotinoids—acetamiprid, clothianidin, dinotefuran, imidacloprid, and thiamethoxam—is ongoing under proposed interim decisions first issued in January 2020.17 EPA's pollinator-protection page lists a series of measures including a 2017 policy restricting agricultural spray and dust applications while bees are under contracted pollination, cancellation of certain residential turf uses of imidacloprid, and a moratorium on new outdoor neonicotinoid registrations pending updated bee data.18 Critics have argued these measures fall well short of the EU framework.
The litigation pipeline is active. On 29 October 2025, the Natural Resources Defense Council filed suit against the EPA for failing to respond to a petition seeking the revocation of all food tolerances for neonicotinoids.7 On 15 January 2026, NRDC announced a proposed settlement with the Minnesota Department of Agriculture over the state's regulation of neonicotinoid-treated crop seeds, following an earlier 2024 NRDC settlement with the California Department of Pesticide Regulation that required the state to reclassify treated seed as a regulated pesticide product.78
States have moved faster than Washington. Maine—which had already eliminated nonagricultural outdoor neonicotinoid use in 2021—signed LD 1323 in July 2025, commissioning the Board of Pesticide Control to study neonicotinoid impacts and report by January 2027. Vermont enacted a phased ban on outdoor uses, and California's Department of Pesticide Regulation issued new pollinator-zone restrictions effective January 2025. Illinois, New York, Rhode Island, Minnesota, and Washington have enacted varying restrictions on agricultural or non-agricultural use.819
The Monarch Listing
On 12 December 2024, the U.S. Fish and Wildlife Service published a proposed rule in the Federal Register to list the monarch butterfly (Danaus plexippus plexippus) as threatened under the Endangered Species Act, accompanied by a Section 4(d) rule and a proposed designation of approximately 4,500 acres of overwintering critical habitat in coastal California from Marin to Ventura counties. Public comments closed on 19 May 2025 after a 60-day extension.620
If finalized as proposed, this would be the largest single-species listing in ESA history, applying to the entire lower 48 states. As of December 2025, however, the rule has been moved from "proposed" to "long-term action" status in the federal Unified Agenda, indicating that no final decision is expected for at least another year.20 Eastern migratory monarch populations have declined by more than 80 percent since the 1980s; the western migratory population reached a low of approximately 1,900 individuals in winter 2019–2020 before partially recovering above 200,000.
What Comes Next
The science of pollination has, in a single year, gained two capabilities that were previously aspirational. The first is a forensic-grade understanding of why the 2025 commercial bee collapse happened, down to a specific virus pair and a specific genetic marker for miticide resistance. The second is a sensing technology—micro-Doppler radar classification—that promises to turn any flowering field into a continuously monitored experimental plot, identifying which insect species are doing real pollination work in real time.
What it has not yet gained is policy coherence. The EU is moving toward import bans on residue from compounds it has already banned domestically, while the U.S. EPA's review of the same compounds drags into a second decade of partial actions and litigation. The Endangered Species Act process for the most charismatic American pollinator has slipped from a December 2025 expected decision to an open-ended timeline. State-level rules vary so widely that the same neonicotinoid-treated soybean seed is treated as a regulated pesticide in Minnesota and California and as ordinary commerce in most of the rest of the country.
The policy lag is the more dangerous of the two gaps, because the biological gap is closing fast. By the time the regulatory architecture catches up to the science, networked millimeter-wave sensors may well be telling us, flower by flower and field by field, exactly which species we have already lost.
Verified Sources
- Project Apis m. and American Beekeeping Federation Survey,
reported in Auburn University College of Agriculture, "U.S. Beekeeping
Survey Reveals Highest Honey Bee Colony Losses During 2024–2025," June
2025.
https://agriculture.auburn.edu/feature/u-s-beekeeping-survey-reveals-highest-honeybee-colony-losses-during-2024-2025/ - USDA Agricultural Research Service, "USDA Researchers Find
Viruses from Miticide Resistant Parasitic Mites are Cause of Recent
Honey Bee Colony Collapses," Press Release, 2 June 2025.
https://www.ars.usda.gov/news-events/news/research-news/2025/usda-researchers-find-viruses-from-miticide-resistant-parasitic-mites-are-cause-of-recent-honey-bee-colony-collapses/ - IUCN, "Mounting Risks Threaten Survival of Wild European
Pollinators – IUCN Red List," Press Release, 11 October 2025. Abu Dhabi,
UAE.
https://iucn.org/press-release/202510/mounting-risks-threaten-survival-wild-european-pollinators-iucn-red-list - Timberlake, T. P., et al., "Pollinators support the nutrition and income of vulnerable communities," Nature, 6 May 2026. DOI: 10.1038/s41586-026-10421-x.
https://www.nature.com/articles/s41586-026-10421-x - Antony, L., White, C., Marchetti, N., Donohue, I., Stout,
J. C., and Narbudowicz, A., "Harnessing mmWave signals and machine
learning for noninvasive taxonomic classification of insects," PNAS Nexus, vol. 5, no. 4, pgag096, April 2026. DOI: 10.1093/pnasnexus/pgag096.
https://academic.oup.com/pnasnexus/article/5/4/pgag096/8662959 - U.S. Fish and Wildlife Service, "Endangered and Threatened
Wildlife and Plants; Threatened Species Status With Section 4(d) Rule
for Monarch Butterfly and Designation of Critical Habitat," Federal Register, vol. 89, FR Doc. 2024-28855, 12 December 2024. Docket No. FWS-R3-ES-2024-0137.
https://www.federalregister.gov/documents/2024/12/12/2024-28855/endangered-and-threatened-wildlife-and-plants-threatened-species-status-with-section-4d-rule-for - Natural Resources Defense Council, "Pollinator Litigation
Press Releases" (NRDC v. EPA filed 29 October 2025; Minnesota Dept. of
Agriculture proposed settlement, 15 January 2026).
https://www.nrdc.org/press-releases/court-strikes-down-glyphosate-decision - Beyond Pesticides, "With State Legislation Focused on
Restricting Bee-Killing Pesticides, Advocates Call for Organic
Transition," Daily News Blog, 2 October 2025; and "Study Cites Ban of
Bee-Killing Pesticides in EU, Inaction in U.S. and Canada," 4 September
2025.
https://beyondpesticides.org/dailynewsblog/2025/10/with-state-legislation-focused-on-restricting-bee-killing-pesticides-advocates-call-for-organic-transition/ - Trinity College Dublin / Phys.org, "Bee More Specific: New
Radar Tech Could Improve Identification and Tracking of Key
Pollinators," 9 May 2026.
https://phys.org/news/2026-05-bee-specific-radar-tech-identification.html - Auburn University / Apiary Inspectors of America /
Project Apis m., "U.S. Beekeeping Survey 2024–2025," reported June 2025.
(Annual losses 55.6%, range 34.3%–90.5%; winter losses 40.2%.)
https://agriculture.auburn.edu/feature/u-s-beekeeping-survey-reveals-highest-honeybee-colony-losses-during-2024-2025/ - Lamas, Z. S., Evans, J. D., et al., "Viruses and vectors tied to honey bee colony losses," PLOS Pathogens, 23 February 2026.
https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1013939 - Klein, A.-M., et al., "Importance of pollinators in changing landscapes for world crops," Proceedings of the Royal Society B,
274:303–313, 2007 (foundational figure: 87 of leading global food
crops, ~35% of crop production volume); cited in CABI Reviews (2024).
https://www.cabidigitallibrary.org/doi/10.1079/cabireviews.2024.0016 - "Pollinator declines, international trade and global food security: Reassessing the global economic and nutritional impacts," Ecological Economics, February 2025.
https://www.sciencedirect.com/science/article/pii/S0921800925000485 - "The economic, agricultural, and food security repercussions of a wild pollinator collapse in Europe," Nature Communications, November 2025. Article s41467-025-65414-7.
https://www.nature.com/articles/s41467-025-65414-7 - University of Bristol, "Fewer Insects, Fewer Nutritious
Crops: Pollinator Decline Puts Our Health at Risk," News Release, 6 May
2026.
https://www.bristol.ac.uk/news/2026/may/fewer-insects-fewer-nutritious-crops.html - Dentzman, K., et al., "An overview of agricultural neonicotinoid regulation in the EU, Canada, and the United States," Pest Management Science, August 2025. DOI: 10.1002/ps.70126.
https://scijournals.onlinelibrary.wiley.com/doi/10.1002/ps.70126 - U.S. Environmental Protection Agency, "Schedule for Review of Neonicotinoid Pesticides," updated 2025.
https://www.epa.gov/pollinator-protection/schedule-review-neonicotinoid-pesticides - U.S. Environmental Protection Agency, "EPA Actions to Protect Pollinators."
https://www.epa.gov/pollinator-protection/epa-actions-protect-pollinators - Bright Lane Gardens, "Neonicotinoids in 2025: Federal
Reviews, State Bans, and Garden Choices" (state-by-state regulatory
summary, with citations to Vermont legislation and California DPR
rulemaking).
https://brightlanegardens.com/gardening-basics/organic-gardening/neonicotinoids-garden-choices/ - Monarch Joint Venture, "United States Endangered Species
Act Status," updated January 2026; and "Monarch Butterfly Listing
Update: What 'Long-Term Action' Means."
https://monarchjointventure.org/monarch-biology/status/esa
https://monarchjointventure.org/blog/monarch-butterfly-listing-update-what-long-term-actions-means
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