Microdon Mirabilis

Hover flies (family Syrphidae) of the genus ''Microdon'' are unusual among the Diptera. Like other members of the subfamily, they are myrmecophiles, meaning they inhabit the nests of ants.

There are 249 species known worldwide, with the greatest diversity being from the tropics; 30 species are known from North America, though it is expected that many of these species will be placed in other genera in time, as ''Microdon'' has been used as a catch-all for various unrelated species not placed in other genera.

Appearance

''Microdon'' adults look more or less like typical flies. Like some other hoverflies, they are generally robust and very hairy, often closely resembling bees. They are between 8 and 15 mm long. The antennae are rather long, with the last (third) segment nearly as long as, or sometimes significantly longer than, the first segment; the antennae are nearly as long as the fly's face. These flies are covered in black or pale (white or golden) hairs, and are themselves either black or metallic green or blue. The scutellum is with apical calcars and wing vein R4+5 with an appendix. They have simple legs and abdomens.

The real oddity of the genus ''Microdon'' is in its larvae and pupae. These are dome-shaped and look like stout little slugs. Their appearance originally led scientists to describe them as mollusks and scale insects. They are slow-moving. Most have the spiracles on a peg-like protuberance extending from the end of their abdomens.

Behaviour

Adult ''Microdon'' flies do not behave like other syrphid flies; they do not hover around flowers, but instead remain very near the ant colonies which serve as larval hosts.

Larvae may be found very deep in ant colonies. Some species actively feed on ant larvae in the colony, others are speculated to be scavengers. ''Microdon'' larvae are more or less restricted in their ant host species. Some ''Microdon'' species have only ever been found in the colonies of a single ant species, while others are restricted to related ant species or genera. Because these flies have such cryptic life cycles, biological information on most species is limited.

Species

''Microdon'' is divided into six subgenera (including ''Microdon'' ''sensu stricto''), plus five species groups and some unplaced species in ''Microdon'' ''sensu lato''.

Subgenus ''Chymophila''

Nearctic:

* ''Microdon fulgens'' Wiedemann, 1830 (Synonyms: ''Microdon euglossoides'' Gray, 1832; ''Chymophila splendens'' Macquart, 1834)

Neotropical:

Oriental:

Palaearctic:
* '' Microdon katsurai'' Maruyama & Hironaga, 2004

Subgenus ''Dimeraspis''

*'' Microdon abditus'' Thompson, 1981
*'' Microdon adventitius'' Thompson, 1981
*'' Microdon fuscipennis'' (Macquart, 1834)
*'' Microdon globosus'' (Fabricius, 1805)?
*'' Microdon marmoratum'' Bigot, 1884
*''Microdon remotus'' Knab, 1917

Subgenus ''Megodon''

*'' M. planitarsus'' Keiser, 1971
*'' M. stuckenbergi'' (Keiser, 1971)

Subgenus ''Microdon'' ''sensu stricto''

Nearctic:

Neotropical:

Oriental:

Palaearctic:

Subgenus ''Myiacerapis''

''Myiacerapis'' is a subgenus of the hoverfly genus ''Microdon''. It contains only one species, ''Microdon villosus.'' It is native to Uganda, though an undescribed species is known from South Africa. Larvae are found in ant nests.

Subgenus ''Syrphipogon''

There are two species described in ''Syrphipogon'':
*'' M. fucatissimus'' (Hull, 1937)
*'' M. gaigei'' Steyskal, 1953

''Microdon'' ''sensu lato'' species groups

''craigheadii''-group

Nearctic:
* '' Microdon craigheadii'' Walton, 1912

''erythros''-group

Afrotropical:
* ''Microdon erythros'' Bezzi, 1908
:= ''Microdon erytherus'' Bezzi, 1921 (misspelling)
* '' Microdon luteiventris'' Bezzi, 1915

''mirabilis''-group

Neotropical:
* '' Microdon bertonii'' Bezzi, 1910
:= ''Microdon arcuata'' Curran, 1941
* '' Microdon iheringi'' Bezzi, 1910
* '' Microdon mirabilis'' Williston, 1888

''tarsalis''-group

Afrotropical:
* '' Microdon tarsalis'' Hervé-Bazin, 1913
:= ''Microdon bequaerti'' Curran, 1929

Unplaced species

Afrotropical

*'' Microdon harinhalai'' (Reemer, 2015)
*'' Microdon berobak'' (Reemer, 2015)
*'' Microdon ifanadiana'' (Reemer, 2015)
*'' Microdon irwini'' (Reemer, 2015)
*'' Microdon janne'' (Reemer, 2015)
*'' Microdon sava'' (Reemer, 2015)
* '' Microdon tsara'' Keiser, 1971

Australian / Oceanian:
* '' Microdon amabilis'' Ferguson, 1926
* '' Microdon macquariensis'' Ferguson, 1926
* '' Microdon nigromarginalis'' Curran & Bryan, 1926
* '' Microdon pictipennis'' ( Macquart, 1850)
:= ''Microdon pictulipennis'' Hull, 1944
* '' Microdon rieki'' Paramonov, 1957
* '' Microdon waterhousei'' Ferguson, 1926

Oriental:
* '' Microdon carbonarius'' Brunetti, 1923
* ''Microdon pagdeni'' Curran, 1942
* '' Microdon trimacula'' Curran, 1928
* ''Microdon unicolor'' Brunetti, 1915

References

{{Taxonbar, from=Q115951

Hoverfly genera
Microdontinae
Myrmecology
Taxa named by Johann Wilhelm Meigen
Brachycera tribes