Overview
A very large, cosmopolitan family of, usually, stoutly built flies, of small to large size, and mostly with very characteristic venation. Almost 5000 species have been described worldwide (Evenhuis & Greathead 1999), and around 370 have been described from Australia, with many more species awaiting description. Nine of the 15 recognised subfamilies (Yeates 1994) are found here, and a key to these subfamilies is available (Lambkin et al. 2003). Most Australian species belong to the subfamilies Bombyliinae, Anthracinae and Lomatiinae. There have been a number of taxonomic revisions of Australian bombyliid genera and tribes over the past 15 years, greatly increasing our knowledge of the fauna and their relationships.
One of the very diverse subfamilies, with some 200 species, is the Lomatiinae, in which the occiput has a deep central cavity, the posterior eye-margins are indented, and Rs forks well before r-m (Yeates 1988, 1991a, 1991b). Most species belong to the great genus
Comptosia
, an 'Antarctic' element, closely related to
Lyophlaeba
of South America (Yeates 1990). The Anthracinae, which resemble the Lomatiinae, but with Rs forking close to r-m, are well represented, mainly by the cosmopolitan
Anthrax
,
Ligyra
,
Villa
, and a number of endemic genera (Yeates & Lambkin 1998; Lambkin et al. 2003). The subfamily Bombyliinae includes many Australian species, principally of
Staurostichus
, with smaller numbers of
Sisyromyia
,
Meomyia
and other genera. Most are stout and hairy, with long, slender proboscis and 1-segmented palp; the abdomen is broad and oval, the tibiae spinose, and, in many, vein M1 meets R5 before the wing margin (Evenhuis 1983; Bowden 1985).
The adults favour warm, sunny localities. Although occurring throughout the continent, they form a particularly characteristic element of the fauna in the more arid climates. Most have a strong, hovering flight, and are commonly taken hovering above, or resting on, blossom or patches of bare earth. Adults are generally pollen and nectar feeders, and many species are important pollinators of native plants, and even horticultural crops (see Heard et al. 1990). Many species can be collected congregating on hilltops, demonstrating a landmark-based mating system (Dodson & Yeates 1990; Yeates & Dodson 1990; Lambkin et al. 2003). Females in most subfamilies have the extraordinary habit of gathering sand-grains in a special chamber at the apex of the abdomen for use as a coating on the eggs (Muhlenberg 1971; Yeates 1994). The larvae are parasites in eggs or larvae of other insects, and a few are predatory (Yeates & Greathead 1997). Little is known about the life histories of Australian species, but some are known to parasitise Hymenoptera and Lepidoptera, and several have been reared from Diptera (Asilidae, Therevidae and Mydidae) and Neuroptera.
Ligyra satyrus
is a hyperparasitoid of tiphiid larvae (Yeates et al. 1999).
Description
In Australia, wing-spans vary from over 70 mm in
Comptosia neuria
down to some 3.5 mm in the tiny
Glabellula australis
. A few, e.g.
Systropus flavoornatus
, are remarkable wasp mimics; in others, mostly members of the subfamily Bombyliinae, the stout, hairy body and long, thin proboscis, together with their flight habits, have earned them the vernacular name 'bee flies'.
Distribution
The adults are common in semi-arid environments, woodlands and heathlands of Australia. Most species are active in spring and summer. Only a few species are known from rainforests (e.g.
Comptosia brunnea
). Species diversity tends to be higher in warmer latitudes, and in the south-west of Western Australia.