Researchers analyzing DNA from more than 1.6 million insects in Costa Rica estimate the planet may host at least 14 million—and possibly 20 million—species. The work, published June 29 in the Proceedings of the National Academy of Sciences, sharply raises earl
For years, scientists have tried to answer a deceptively simple question: how many insect species are actually out there? Now a DNA-based survey is forcing that number upward—fast.
A new estimate suggests Earth may be home to at least 14 million to 20 million insect species. The researchers reported the estimate on June 29 in the Proceedings of the National Academy of Sciences. It roughly doubles or triples most other recent figures, which have put the count around 6 million species. Only around 1 million insects have officially been named and described.
The timing matters because insects are in trouble. Many are facing an “Insect Apocalypse,” with numbers dwindling due to pesticides, climate change, habitat destruction, and light pollution. The updated species range is intended to serve as a baseline—an attempt to better pin down how many different kinds of insects may exist. including many yet-to-be-discovered species that. like known species. may also be at risk.
The study was anchored in a single. intensely studied slice of life: Área de Conservación Guanacaste. a protected area and World Heritage Site in northwestern Costa Rica. Cornell University entomologist and biodiversity scientist Laura Melissa Guzman said the site is a strong starting point because it has been well-studied. Researchers have used the traps and other methods to monitor insects across the area’s dry forest. rainforest and cloud forest ecosystems. spanning from ocean to mountain. for more than 40 years.
Guzman and colleagues analyzed the DNA of more than 1.6 million insects belonging to roughly 54. 000 species that were caught in traps set up in the conservation area. “It helps us understand how much we could be losing,” Guzman said. “And that we have to keep studying these insects to better protect them.”.
To get from a big sample to a global estimate, the team didn’t just count what turned up. They examined a specific group that is diverse but still poorly understood: parasitoid wasps. The analysis focused on more than 11,000 parasitoid wasp specimens across 388 species.
That wasp census allowed the researchers to use statistical methods to estimate how many species might have been missed even among a large haul of more than a million insects. Their conclusion: roughly 2,400 parasitoid wasps may call Área de Conservación Guanacaste home, along with more than 300,000 other insect species. From there, they upscaled those figures to determine what might exist around the globe.
Even at the low end, the study’s estimate of 14 million suggests there are millions of species still waiting to be discovered. “It’s humbling how much we don’t know,” Guzman said. “And how much we have left to know.”
insects insect diversity DNA analysis Costa Rica Área de Conservación Guanacaste parasitoid wasps biodiversity pesticides climate change habitat destruction light pollution Proceedings of the National Academy of Sciences