Scientists may have underestimated one of the planet's most diverse life forms by a wide margin. A new study suggests Earth could host between 14 million and 20 million insect species, far above the long-used estimate of about 6 million.
A New Benchmark for Biodiversity
Researchers reached this figure by studying insect diversity in Costa Rica's Área de Conservación Guanacaste, a protected region that combines dry forest, cloud forest, and rainforest. Using more than 1.6 million tropical insect specimens gathered from Malaise traps and DNA barcoding, the team identified tens of thousands of species in a single area.
The analysis then focused on Microgastrinae, a highly diverse group of tiny parasitoid wasps. By combining trap data, peripheral sampling, and caterpillar-reared specimens, the scientists recorded 1,414 species in that group alone. From there, statistical modeling suggested the protected area may contain nearly 333,000 insect species.
Why the Count Matters
The study, published in Proceedings of the National Academy of Sciences, also offers a broader message: many insects remain unnamed and unrecorded. That makes it harder to measure how species respond to climate shifts, habitat change, and other environmental pressures.
Laura Melissa Guzman of Cornell University, one of the study's authors, said a reliable baseline is essential for understanding biodiversity and tracking long-term changes. Co-author Michael Sharkey, a taxonomist known for his work on insect classification, helped shape the approach by showing how parasitoid wasps can serve as a powerful window into overall insect diversity.
The researchers describe their estimate as a conservative lower bound, meaning the real number could be even higher. Their work does not close the book on insect life; it expands the map. In the years ahead, such methods may help science identify hidden species faster and strengthen global conservation planning.