Identification difficulty = 2.
according to Ball & Morris, 20241
The larva inhabits seepages, brooks and small water bodies in woodland and scrub. It develops within decaying vegetation and rich mud in very shallow water. Adults are usually seen on the flowers of white umbels such as Hogweed Heracleum sphondylium, Wild Angelica Angelica sylvestris, Hemlock Water Dropwort Oenanthe croccata and Upright Hedge Parsley Torilis japonica, especially in damp shady locations.
The following plots show the number of unique records per week that were not reported to be of eggs, larvae or pupae.
Better levels of recording start to highlight gaps in this species' occurrence that may reflect genuine absences rather than recorder effort. Its overall distribution is widespread and common, but there are notable gaps from parts of eastern England and east Lancashire. Absences from the west coast of Scotland may be an artefact of recorder effort.
The following plots show the Frescalo TFactor vs year and a map of the rescaled frequency (all records) for the species. For an explanation see here.
Ball, S., & Morris, R. (2024). Hoverflies of Britain and Ireland. WILDGuides (3rd ed.). Oxford: Princeton University Press. ↩