Mormotomyia hirsuta, the Terrible Hairy Fly
Well, they can’t all be beautiful. As an introduction to the 2nd half of our year-long “insect of the week” project we address this omission by offering a decidedly nasty-looking, if very interesting, species, as our insect of week 27. In 1933 Major Harry Barron Sharpe of the colonial service (he was District commissioner of Garissa District) collected two males of a strange-looking fly from a cave in Ukasi, eastern Kenya. The species has strap-like remnants of the wings (useless for flying) and is covered with long, fine hairs. It lacks ocelli, has reduced, lozenge-shaped eyes and superficially resembles individuals of certain arachnoid groups such as spiders and solfugids. The specimens were duly deposited in the British Museum (Natural History), and there they rested until the dipterist Ernest Edward Austen came across them in the collection and, recognizing their singular aspect, described them as representing a new family, new genus and new species (Mormotomyiidae: Mormotomyia hirsuta Austen 1936, “the terrible hairy fly”). Twelve years later the legendary Kenyan ornithologist/entomologist Victor Gurner Logan van Someren found the flies at the same location from which the original specimens were collected. Subsequently and for the next 60 years there were no further sightings of Mormotomyia. During this extended period of absence, the reputation of the species grew to legendary status, ultimately being declared the rarest fly in the world by the late, celebrated Smithsonian dipterist Christian Thompson (no mean feat considering there are more than 110,000 species of Diptera). In 2008 an expedition led by ICIPE scientists was organized, to determine the type locality of the species and perhaps (!) to find specimens. Although Mormotomyia were not observed during the field trip we did identify the probable type habitat, a large ca. 20 meter-high boulder on the top of Ukasi Hill. A further expedition was organized to coincide with the onset of the rainy season of 2010 and this effort was rewarded with the “rediscovery” of the species, with numbers of adult and juvenile specimens observed on or around bat guano that had been washed out of a narrow horizontal cleft in the stone (see the accompanying figure with arrow pointing to the cleft). But was Mormotomyia restricted to this one location? With funding provided by the Mohamed Bin Zayed Species Conservation Fund we looked for evidence of Mormotomyia in many locations throughout dry eastern Kenya and were lucky enough to find living specimens at three more sites, two on hills near Ukasi and a further site nearly 200 km south of it. It appears that the species is more common than previously thought. Both its macrohabitat (inselbergs) and microhabitat, (horizontal fissures) are widely distributed throughout arid eastern Kenya, and the conservation status of Mormotomyia is probably robust.
Credits: Dr Robert Copeland