40-Million-Year-Old Predatory Insect Found Trapped in Amber

Scientists have uncovered a rare predatory insect, Robsonomyia henningseni, trapped in 40-million-year-old amber, offering new clues about ancient ecosystems. The discovery of this previously unknown species, which was found in a piece of Baltic amber, reveals how this genus once thrived across the Northern Hemisphere before shifting southward over millions of years. The fossilised fungus gnat was part of a 70,000-specimen collection at the Natural History Museum of Denmark. While the insect appears lifelike, its DNA cannot be extracted due to extensive chemical changes over time. The species name henningseni honours C.V. Henningsen, a Danish collector who discovered the original amber piece in 1961. Researchers also identified a second new species, Robsonomyia baltica, named after the Baltic region where it was unearthed. Both finds belong to a genus that once spread across North America and Europe but later retreated to tropical zones in the Neotropics and Southeast Asia. Robsonomyia henningseni was a predator, using sticky, acid-coated webs to capture small invertebrates. Its discovery bridges a gap between two living gnat species—one in Japan, the other in the United States—separated today by nearly 8,000 kilometres. The fossil provides critical evidence of how climate shifts during the Oligocene and Miocene epochs pushed the genus toward warmer regions. Similar migration patterns appear in other insects, such as bees (Electrapis) and ants (Formicium), which moved from Europe and Laurasia to Asia and Gondwanan fragments. Studies, including those by Engel on Eocene Hymenoptera and Michez et al. in Palaeogeography, Palaeoclimatology, Palaeoecology, support these findings, showing how ancient climate changes reshaped insect distributions. The discovery of Robsonomyia henningseni confirms that this genus once occupied a far wider range across the Northern Hemisphere. By studying its fossil record, scientists can now trace how cooling climates forced its gradual migration to tropical regions. The findings also highlight amber's role in preserving long-extinct species, offering direct insights into evolutionary shifts over tens of millions of years.