This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: A bumblebee-like insect that was last seen in France 150 years ago was spotted again in the Paris region in 2025. Had the creature, known by its scientific name Pocota personata, disappeared and returned after all those years?
Or did it simply fly around unnoticed this whole time? The mystery illustrates the challenge facing scientists seeking to catalog the world's biodiversity, as so much of nature remains poorly understood. The gap in scientific data on the state of species could feature prominently at the U.N.'s COP17 biodiversity summit opening Monday in Armenia, where countries will take stock of progress in commitments to protect nature.
To close that gap in France, the National Museum of Natural History (MNHN) and the National Centre for Scientific Research (CNRS) launched a project in June to build a database of the country's plants and invertebrates. "We know biodiversity is declining, but we are sometimes quite helpless when it comes to quantifying it due to a critical lack of data on the current and past monitoring of species," Rodolphe Rougerie, head of the Dynabiod project, told AFP. A 2011 study estimated that 86% of terrestrial species and 91% of marine creatures had yet to be formally described.
Even among identified species, their status is often poorly understood. In 2025, scientists had assessed the extinction risk of only about 8% of known species, according to the International Union for Conservation of Nature. The tools used to identify species include field observations.
While spotting large mammals or certain birds can be relatively simple, the exercise gets trickier when it comes to smaller species, such as insects, fungi or microscopic organisms. Every week, MNHN researcher Fanny Kratz checks large white tents that serve as insect traps at the Jardin des Plantes, a botanical garden in the heart of Paris, and 16 other sites. She then uses their DNA to fill gaps in the data.
The task is "very, very long" and "very, very complicated," she said. A single trap can contain as many as 261 types of DNA, but those genetic traces do not necessarily correspond to 261 different species. And there are always a few "unknowns"—DNA that does not match with anything in existing databases.
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