DIPTERA > BRACHYCERA | Higher Diptera

MUSCOMORPHA > ASCHIZA > Lonchopteroidea > Lonchopteridae (7 species)

(subfamilies: none)

A small family of just seven species that are characterised by their long-pointed wings. They are slender, yellowish to brownish-black flies that vary in size from just 2-5mm. The head is rounded and wide, with moderately large eyes; the third antennal segment is bulbous and the arista long; the head, body and legs have some well-developed bristles; the wings are clear or tinged, without markings, and somewhat pointed apically; the wing venation is distinct and sexually dimorphic, the anal vein continuing to the margin and terminating freely in the male, but intersecting with CuA1 in the female; the veins run longitudinally and are without crossveins apart from at the base; most veins have some black setae on the dorsal surface.

Species are within a single genus Lonchoptera, the most frequently observed being Lonchoptera lutea, commonly known as the Yellow Spear-winged Fly. It is by far the most recorded species on the NBN Atlas, followed by Lonchoptera bifurcata, the two combined accounting for almost 90% of the total records. The remaining species obviously have very few official sightings. Surprisingly though, Lonchoptera lutea has only been officially recorded in Dorset three times over the past ten years, and Loncoptera bifurcata not once since 2009. Clearly these species are poorly recorded, so we have to accept that the data only provides a broad indication and that some species do occur more frequently and can likely be found in areas where they haven't been officially recorded.

Lonchoptera lutea is widely regarded as the 'type species' of the genus. Adults are quite variable, ranging in colour from yellow to dark brown. Separation from other Lonchoptera species is mostly down to bristles on the front tibiae at a level of detail that I probably wouldn't be able to determine. The only other feature that I've picked up on, is in respect of the colour of the antennal segments, particularly the third, which tends to imply that's not the case with other species. However, I've found two conflicting descriptions, one saying that the first and second segments are yellowish or certainly paler, but the third is dark, and another saying all segments are dark. I can't find any decent images on the internet where the species is confirmed and the antennae are clear so, at present, have resorted to labelling the following individuals as 'likely' just in case one or the other has been misrepresented. To me the first two look like different species, but with nothing else to go I'll have to accept that they are indeed variable.

Adults feed on nectar and can be found in various habitats from April to October. Whereas other Lonchoptera species seem to favour shaded, often moist places alongside running or stagnant waters, or in marshes and damp woodlands, Lonchoptera lutea is more likely to be encountered in more open and exposed habitats. That said, most of my sightings have been in woodland, albeit along relatively wide, unenclosed paths.

Updated Nov.24 (v.2)