New Cornell-linked research estimates there may be 14 million to 20 million insect species worldwide, far more than the long-standing estimate of about 6 million. The study says the larger count could change how scientists understand biodiversity and the number of species that remain undiscovered.
The study was published June 29 in the Proceedings of the National Academy of Sciences.
Scientists have described about 1.2 million insect species so far, according to the Cornell Chronicle. Laura Melissa Guzman, an assistant professor in Cornell's Department of Entomology and corresponding author of the paper, said understanding how many species exist is essential to protecting them.
Researchers used genetic information from 1.6 million tropical insect specimens, a census of parasitoid wasps in Costa Rica and statistical methods to estimate the number of unobserved species.
The team studied the Area de Conservacion Guanacaste, a protected area in northwestern Costa Rica, and focused in part on Microgastrinae, a diverse group of small parasitoid wasps. Those wasps lay eggs inside caterpillars, and their larvae emerge after feeding inside the host.
Fifteen core Malaise traps captured more than 1.6 million insects, all of which were barcoded through DNA sequencing. Those traps yielded nearly 54,000 insect species.
The researchers estimated that the protected area may contain about 333,000 insect species, then used comparisons with trees, mammals, amphibians and moths to estimate global insect diversity.
Guzman said many undescribed insects may already be declining before scientists have identified them.
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