In the coffee fields and shaded parkland of Hawaii, scientists are following mosquitoes with the help of technology so small it fits three to four times over inside a 12-point-font period. These harmonic radar tags—tiny devices consisting of just two flexible wires and a semiconductor diode—are revolutionizing how researchers understand one of the world's deadliest animals, and what they're learning could transform disease prevention globally.
For decades, tracking mosquitoes in the wild has been nearly impossible. While scientists have long tagged and studied birds, fish, and larger insects, the mosquito's diminutive size made traditional tracking methods impractical. Researchers have tried carbon dioxide traps and even trained dogs to sniff out hiding insects, but none revealed the full picture of how mosquitoes actually move through their environments. That gap in knowledge matters enormously: mosquitoes transmit West Nile virus, Zika virus, malaria, and other pathogens that sicken and kill hundreds of thousands of people every year. Understanding their behavior is crucial to controlling populations and preventing disease.
Enter Jennifer K. Peterson, an assistant professor and medical entomologist at the University of Delaware, who partnered with Matthew Siderhurst, a research biologist with the U.S. Department of Agriculture's Agricultural Research Service based in Hawaii. Siderhurst had successfully used harmonic radar tags on larger insects since the 1980s—beetles, moths, bees, and wasps—and had even helped locate and eradicate murder hornet nests in Washington. But mosquitoes presented a new challenge. "Mosquitoes are three times smaller than anything else we've ever done," Siderhurst said. "They're the deadliest animal in the world. If we don't have a way of understanding their biology, how can we work on control?"
The team captured female tiger mosquitoes—common invasive species in both Hawaii and Delaware—and, under a microscope, Siderhurst's technician Anika Hurst glued the hairline-thin HR tags vertically to the back of each insect's thorax, between head and abdomen. The tags work by harnessing radio frequency signals; researchers then walk through fields and parkland waving handheld detectors—similar to transponders used for backcountry rescue—that locate the insects through beeping signals.
The researchers conducted 12 experiments across varying environments: controlled labs, outdoor screen cages, coffee fields, and shaded parkland. The results, published in PNAS Nexus in 2026, demonstrated that the technology works at this miniature scale. The mosquitoes continued flying freely with the tags attached, revealing previously hidden movement patterns. In coffee fields, researchers documented mosquitoes flying up to 2 meters (about 6.5 feet) above ground before landing at heights less than 1 meter (about 3.3 feet), insights that could reshape how scientists design traps and interventions.
The implications extend far beyond a single species. "As medical entomologists, we want to increase public health preparedness and reduce transmission of vector-borne diseases to humans and animals," Peterson said. This new window into mosquito behavior opens possibilities for targeted control strategies and smarter disease prevention. With harmonic radar tags now proven effective even on insects three times smaller than previously tracked species, researchers can finally see what mosquitoes do in the wild—and work toward stopping them before they spread disease.