Vanishing May Beetles: Scientists Issue Dire Warning

Costa Rican scientists are sounding the alarm as a once-abundant insect species edges toward collapse. Known locally as abejones de mayo, or May beetles, these beetles have long been a sign that the rainy season is near. But this year, they’re conspicuously absent.

According to The Cool Down, the May beetle population has reportedly plummeted by as much as 95% over the past 40 years, University of Costa Rica biologist Andres Arias told The Tico Times. “For many Costa Ricans, spotting abejones buzzing around porch lights marked the start of the rains,” he said. “Now, they’re a fleeting memory.”

Researchers point to a combination of rising global temperatures, rampant pesticide use, and rapid urbanization as the culprits behind this sharp decline. Costa Rica’s heavy pesticide use, reportedly the highest per capita in Latin America, has been especially damaging. As warming alters rainfall patterns and disrupts seasonal cues the beetles depend on, their population struggles to recover.

Arias and his colleagues warn that if action isn’t taken soon, May beetles could vanish entirely. “Losing them means losing a piece of who we are—and a warning we can’t ignore,” he emphasized.

Their disappearance mirrors a troubling global trend: insect populations worldwide have been dropping at alarming rates. A 2023 study from the University of California, Riverside, found that insect numbers globally have fallen by approximately 45% over the last four decades. The World Wildlife Fund has warned that as many as 40% of insect species could face extinction by century’s end.

Insects make up roughly 80% of Earth’s animal life and play a vital role in maintaining ecosystems. They pollinate plants, feed on pests, and provide nourishment for countless other species. The loss of a single species can ripple through entire ecosystems.

Costa Rican lawmakers are now considering a bill to ban pesticides deemed highly toxic by the World Health Organization, a move conservationists hope will help preserve the May beetles and other threatened insect species.

The stakes couldn’t be higher. As Arias put it, “Losing them means losing a piece of who we are.”