Alder Flea Weevil Orchestes testaceus

The Alder Flea Weevil, Orchestes testaceus, is a small beetle belonging to the family Curculionidae, closely associated with alder (Alnus glutinosa) across Britain and Europe. Adults are tiny – typically just 2–3 mm in length – and reddish-brown to testaceous in colour, a characteristic reflected in the species name. Like other members of the Orchestes genus, enlarged hind femora adapted for jumping give rise to the ‘flea weevil’ part of its common name. The larvae are leaf-miners, creating distinctive blotch mines within alder leaves that appear as pale, papery patches on the upper surface – a useful identification feature in the field. It is a rewarding find for entomologists surveying the wetland habitats, carr woodland, and riverside environments where its host tree thrives. Image: © phantomias7, iNaturalist.

Find out more: iNaturalist, UK Beetle recording