Melanagromyza splendida Frick, 1953

Lonsdale, Owen, 2021, Manual of North American Agromyzidae (Diptera, Schizophora), with revision of the fauna of the " Delmarva " states, ZooKeys 1051, pp. 1-481 : 1

Melanagromyza splendida Frick

Figs 297-300

Melanagromyza splendida Frick, 1953b: 207. Spencer 1981: 59; Spencer and Steyskal 1986b: 25; Shi and Gaimari 2015: 72.

Description.

Wing length 1.8-2.6 mm (♂), 1.9-2.6 mm (♀). Length of ultimate section of vein M4 divided by penultimate section: 0.5-0.7. Eye height divided by gena height: 3.9-6.9. Deepest portion of gena 1/3-1/2 distance from anterior margin. Fronto-orbital plate not projecting, sometimes slightly visible in lateral view; strongly swollen in males, 25-28% frons width, narrowing anteriorly; narrower in females, 16-23% frons width; setae inset along inner margin of plate. Clypeus broadly rounded. Ocellar triangle slightly longer than wide.

Chaetotaxy: Two ori with anterior seta strongly displaced anteriorly; two ors. Eye extensively pilose, hairs sparse excluding dense dorsal patch. Orbital setulae erect to reclinate, slightly proclinate anteriorly (mostly inner row), in up to three or four irregular rows; setulae longer in male. Two dorsocentral setae. Acrostichal setulae in eight irregular rows. Mid tibia with two posteromedial setae.

Colouration: Body, including halter, dark brown in base colour. Fronto-orbital plate sometimes whitish along anteromedial margin. Notal colour ranging from brilliant green to dull green with coppery tint. Calypter margin and hairs white. Abdomen metallic green, sometimes bronze (Austin, TX).

Genitalia: (Figs 297-300 ) Epandrium with posterodistal spine. Surstylus <1/2 height of epandrium, distal margin slightly rounded and angled, with several irregular rows of tubercle-like setae along inner-distal surface. Hypandrium subtriangular, long with thin, tapered distal process. Proepiphallus dark and V-shaped. Metepiphallus broad and dark with several sublateral tubercles and lateral ridges. Basiphallus U-shaped. Space between distiphallus and phallophorus less than height of basiphallus. Distiphallus relatively globular with distinct transverse fold laterally on distal 1/3 that curves towards venter; base exceeding that of mesophallus; inner surface only with clusters of shallow bumps (no spines); with short narrow tubule emerging apically below short plate; seen ventrally, width of distiphallus varying from relatively slender (as in illustration) to stouter around middle.

Variation: One AZ male (dissected) with fronto-orbital plate swollen to 1/3 width of frons (ie. similar to M. virens ). Dissected Newark (DE) male, possibly a separate species, differs as follows: dark distoventral process on distiphallus highly reduced, distiphallus slightly more quadrate in outline (seen ventrally), and surstylus not downturned apically, but with long tubercule-like setae typical of M. matricariodes and M. virens ; clypeus distinctly truncated apically and orbit slightly less swollen medially.

Hosts.

Asteraceae - Ambrosia , Bidens , Centaurea *, Cineraria *, Coreopsis *, Erechtites , Flaveria , Gaillardia , Galinsoga *, Gnaphalium , Helianthus , Hymenoxis *, Lactuca , Parthenium , Tagetes , Zinnia . Cucurbitaceae - Cucurbita . Apiaceae - Apium , Daucus . NC record of feeding on potato requires verification.

Distribution.

USA: AZ, CA, DE*, FL, HI, IL, IN*, MD*, MI[?], MO*, NC*, NY[?], SC[?], TX*. Argentina*. Bahamas. Chile. Jamaica. Mexico.

Type material.

Holotype: USA. HI: Kamuela, 5.xii.1950, ex. celery (1♂, USNM).

Paratype: USA. HI: same data as holotype (1♀, USNM).

Additional material examined.

Argentina. Salta: Rt. 34, 4 km S Metan, i.1983, Galinsoga parviflora , tunneling inside stems (1♂ 1♀, USNM), Jujuy: Rt. 9, 1 km S Maimara, 31.xii.1982, Hymenoxis robusta , tunneling inside stem (1♀, USNM). Bahamas. Bimini Isl., 22-31.i.1968, light trap, G.M. Stokes (2♂, USNM). Chile. Valdivia: Santiago, 4.v.1978, 78.3999, reared ex. sunflower stalk (1♂, USNM). USA. AZ: Yuma, 20.v.1968, D.M. Tuttle (2♂ 2♀, USNM), CA: Ortega Hiwy., near summit, 11.vi.1944, A.L. Melander (1♂, USNM), San Simeon, 31.viii.1945, A.L. Melander (1♀, USNM), Orange Co., Fullerton, 13.ii.1969, R.D. Goeden and D.W. Ricker, insectary reared on Ambrosia psilostachya Decandolle (2♂, USNM), Santa Barbara Co., Santa Barbara, 22.iv.1969, R.D. Goeden and D.W. Ricker, insectary reared on Ambrosia psilostachya (2♂ [with puparia], USNM), San Bernardino Co., Highland, 2.v.1969, R.D. Goeden and D.W. Ricker, insectary reared on Ambrosia acanthicarpa Hook. (1♀ [with puparium], USNM), Cucamonga, 20.v.1969, R.D. Goeden and D.W. Ricker, insectary reared on Ambrosia acanthicarpa Hook. (1♀ [with puparium], USNM), Salinas, 1.xi.1930, Bred from [illegible]ule (1♂, USNM), L.A. Co., Westwood Hills, 3.xi.1938, ex Cineraria stems acc. 94 (1♂, USNM), DE: Lum’s Pond, 17.vii.1974, D. Buntin (2♂, USNM), Newark, D. Buntin, 19.viii.1974 (2♂, USNM), 10.vii.1975 (1♂, USNM), 9.vi.1975 (1♂, USNM), FL: Dade Co., Naranja, 12.xii.1985, A.L. Norrbom (1♂, USNM), Highlands Co., Archibold Biological Sta., 24.iii.1969, S.W. Frost, CNC358443 (1♂, CNC), Highland Co., Archibold Biol. Sta., 24.iv.1967, B.V. Peterson, CNC358464 (1♂, CNC), HI: Honolulu, 6.v.1929, ex Cornflower ( Centaurea ), J.F. Illingworth (2♂, USNM), 7.v.1929 (1♂ 1♀, USNM), 8.v.1929 (1♀, USNM), IL: Champaign, tomato leaves, 12.ix.1957, J.F. McAlpine, CNC358451 (1♂, CNC), Alhambra, 24.vi.1937, reared from sunflower, destroying stem, Satterthwaite (4♂ 10♀, USNM), IN: Lafayette, J.M. Aldrich, “vii-21” (1♂, USNM), “x-14” (1♂, USNM), 4.ix.1916 (1♂, USNM), “vii-26” (1♂, USNM), “6-27” (1♂, USNM), “v-23” (1♂, USNM), “v-27” (2♂, USNM), [no date] (1♂, USNM), MD: College Park, 2.viii.1931, C.T. Greene (1♂, USNM), NC: Chadboura, 27.v.1910, feeding on potato, E.G. Smyth (1♂, USNM), MO: Webster Groves, 17.v.1932, Helianthus tuberosa, Satterthwaite (1♀, USNM), [locality not provided, likely Webster Groves], 32165b, Helianthus tuberosa (1♂, USNM), TX: Galveston, vi.1900, A.L. Melander (1♂, USNM), Mexico, in carrot, Laredo, Tx., 31255, 18.i.1943, Lot No. 43-1075 (1♂, USNM), 31457, 13.ii.1943, Lot No. 43-1590 (1♂ 1♀, USNM), Mexico, in carrot root, El Paso, 33818, Lot No. 42-6728 (1♀, USNM).

Comments.

The short, squat distiphallus is highly characteristic of this species, especially the bulging laterodistal region that appears as a transverse fold. Male dissection is recommended for confident identification.

While Melanagromyza splendida has previously been recorded as far north as New York and Michigan in the United States, almost all of the northern males identified by previous authors dissected here have been M. virginiensis . The remaining specimens for which previous Michigan, New York, and South Carolina records of M. splendida were based ( Spencer and Steyskal 1986b) have not been found, and it is suspected that these might also be misidentifications of M. virginiensis .

Several Texas records, which may represent interceptions from Mexico, note carrot as host. When considering the economic significance of carrots, the widespread occurrence of the fly, and the absence of previous rearing records, it is possible that the labels are in error or Daucus is not a preferred host.

Figures

Figures 297 - 300. Melanagromyza splendida Frick, male genitalia 297 external components, left lateral 298 hypandrium, ventral 299 hypandrial complex, left lateral 300 phallus and proepiphallus, ventral.