DIPTERA > BRACHYCERA | Higher Diptera

MUSCOMORPHA > SCHIZOPHORA > Acalypratae > Sciomyzoidea > Heterocheilidae (1 species)

(subfamilies: none)

A small family of coastal flies represented in Britain by a solitary species Heterocheila buccata, which lives along, or in the vicinity of, the strandline of both sandy or rocky shores, and saltmarsh. This type of coastal habitat is also known as the drift or wrack line as it's the upper zone of the beach where the high tide washes up and deposits kelp and seaweed (wrack), as well as driftwood and a variety of both organic and inorganic material. The size and nature of the beach together with the time of year and tides will vary the location of the strandline. In some areas the build-up will be minimal, but in other locations it may accumulate. The best situation is when there is fair amount of organic matter that is deep enough to retain a reasonable degree of moisture, but is not being disturbed by normal tides.

In these areas you are likely to find Heterocheila buccata living in close association with other 'seaweed flies' such as the Coelopa frigida, Coelopa pilipes and Malacomyia sciomyzina kelp flies, the Fucellia strandline anthomyiids, the sepsid species Orygma luctuosum or the predatory scathophagids Ceratinosoma ostiorum and Scathophaga litorea.

Heterocheila buccata is a fairly widespread, although rather localised species, with only a relatively small number of officially confirmed records, most of which are from more northern coastlines. In fact, I was surprised to note that neither the iRecord or NBN Atlas databases include any records along the south coast from West Sussex through to South Devon. I have no idea why, other than the species is far scarcer than it first appears. Or, of course, that it's simply under- recorded, which I will try to help rectify by submitting details of this individual.

The larvae develop specifically in the stipes of Laminaria kelp especially Laminaria digitata, commonly known as oarweed. This glossy, dark brown, broad-frond kelp is usually found attached to bedrock in the lower intertidal or sublittoral zones, but may also be found further up the beach partially buried in sand. It is, therefore, (somewhat contrary to the opening paragraph) often in separate areas of the beach although, when loose, it can still accumulate with washed-up Fucus seaweeds, such as bladder wrack. Every beach will be different and, as previously noted, different situations will be found dependent on the tides and time of year.

Updated, Dec.24 (v.2)