Study reveals millions of insect species remain unidentified

Scientists say only a small fraction of the Earth’s insect species have been identified, with the true number likely far larger than previously thought, according to a study published on Monday (29/6). The research estimates there are up to 20 million insect species worldwide. That figure is much higher than the roughly one million species that have been formally described, as well as previous scientific estimates of around six million species. The study, published in the journal Proceedings of the National Academy of Sciences, used statistical modelling based on insect surveys in Guanacaste National Park, Costa Rica. The researchers focused on parasitoid wasps, a highly diverse group of insects known for laying their eggs inside other insects. By comparing various survey methods, including trap data and analysis of caterpillars infected by parasitoids, the researchers found that only a few species were identified through both methods. The findings suggest that even intensive sampling can only reveal a small portion of insect diversity in a given area. Using statistical techniques originally developed in epidemiology to estimate hidden populations, the research team calculated that Guanacaste National Park alone likely harbours more than 300,000 insect species, far more than previously recorded. They then extrapolated this calculation to a global level by comparing insect biodiversity and tree species. The results indicate that Earth is likely home to between roughly 13 million and nearly 25 million insect species, with an average estimate of around 20 million species. Brian Fisher, curator of entomology at the California Academy of Sciences, said the estimate shows the figures used so far are likely well below the actual number. However, he stressed that the exact number of insect species remains uncertain. The researchers said the study illustrates the vast scale of undiscovered biodiversity while also highlighting the challenges for conservation efforts. Many insect species are believed to be experiencing population declines due to habitat loss, climate change, and other environmental pressures. According to experts, the findings show that most insect life on Earth remains unknown and risks disappearing before it can be documented by science.