Hover fly

Eristalis rupium is a hoverfly in the family Syrphidae, recognisable by the black-and-yellow banded abdomen and large compound eyes typical of the genus, which includes several bee-mimicking species. Adults feed on nectar and pollen, making them contributors to pollination of wetland and meadow flora, while larvae are aquatic filter-feeders (so-called "rat-tailed maggots") that develop in waterlogged, organically rich substrates such as bog pools and fen margins. Adults are often observed hovering and darting between flowering plants in open, damp habitats.

The species has a wide but scattered distribution across Europe, extending from Fennoscandia and the Baltic states through central and western Europe to the Balkans and Iberia, with additional records from Russia, Georgia, Mongolia, and disjunct populations reported in North America and Australia. It is closely tied to bog, fen, and other wetland ecosystems where larval habitat remains intact.

Its endangered status stems from the ongoing loss and fragmentation of these wetland habitats through drainage and conversion for agriculture, as well as agricultural intensification that alters hydrology and water chemistry. Water pollution and eutrophication degrade the specific breeding conditions larvae require, while climate change is altering wetland water levels and seasonal patterns. Urban expansion further reduces and isolates remaining suitable patches.

Conservation efforts include wetland protection and restoration initiatives within protected areas across parts of its European range, alongside broader peatland conservation programs. Population trends remain unknown due to limited monitoring data. Given the continued degradation of bog and fen habitats across much of its range, the species' long-term outlook depends heavily on the success of wetland conservation and hydrological restoration efforts currently underway.