Liriomyza brassicae (Riley)

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

Liriomyza brassicae (Riley)

Figs 588-594

Phytomyza diminuta . Nomen dubium. Walker, 1858: 233. Frick 1952a [synonymy].

Oscinis brassicae Riley 1884: 322.

Agromyza pascuum Meigen, 1830. Misidentification. Melander 1913: 258; Frick 1952a: 402.

Liriomyza cruciferarum Hering, 1927: 461. Frick 1952a: 402 [tentative synonymy, not maintained here].

Liriomyza brassicae . Frick, 1952a: 402, 1957: 68, 1959: 402, Spencer 1963: 356, 1969: 170; Spencer and Steyskal 1986: 127; Scheffer et al. 2007: 772; Lonsdale 2011: 33, 2017: 37; Scheffer and Lonsdale 2018: 87; Eiseman and Lonsdale 2018: 48.

Agromyza diminuta Walker. Misidentification, in part. Coquillett 1898: 78.

Phytomyza mitis Curran, 1931: 97. Frick 1952a: 427, 1959: 402. Spencer 1967 [synonymy not explicit].

Liriomyza hawaiiensis Frick, 1952b: 513. Spencer 1963 [synonymy].

Liriomyza bulnesiae Spencer, 1963: 360. Spencer and Stegmaier 1973 [synonymy].

Liriomyza ornephila Garg, 1971: 241. Sasakawa 1977 [synonymy].

Description.

Wing length 1.2-1.6 mm (♂), 1.7-1.8 mm (♀). Length of ultimate section of vein M4 divided by penultimate section: 2.5-3.5. Eye height divided by gena height: 2.9-5.0. Scutum shiny.

Chaetotaxy: Two or rarely three ori; two ors. Acrostichal setulae in four rows.

Colouration: Lateral margin of frons sometimes with narrow brown margin, varying in strength from indistinct (common) to reaching base of fronto-orbitals; posterolateral corner of frons brown to base of inner or outer vertical seta, sometimes light brown between bases of setae; remainder of head light yellow with back of head and ocellar triangle brown. Scutum dark brown with complete lateral yellow stripe. Scutellum yellow with lateral corner brown. Katatergite yellow with posteroventral margin brown; anatergite light brown with dorsum yellow; mediotergite dark brown. Anepisternum usually with most of ventral margin brown, although sometimes also with posterior margin broadly pigmented or only with small anteroventral spot; anepimeron mottled; meron brown with dorsal 1/3 yellow; katepisternum with large brown triangular spot (not enclosing seta). Calypter margin and hairs grey. Legs yellow with tibiae, tarsi and base of fore coxa brown (fore and mid legs paler, particularly towards apex); sometimes base of femora (often only dorsally) and scraper on hind femur brown; uncommonly with brown streaking on fore femur, but if present, then lateral margin of frons narrowly brown, dark line present between base of vertical setae and hind coxa brown. Abdomen brown with lateral and sometimes posterior margin of tergites 2-4 yellow; tergite 2 sometimes with yellowish mottling and tergites 2-4 sometimes with narrow medial dividing yellow line, and tergite 4 often nearly divided medially into two pairs of spots; tergite 5 and sometimes 6 yellow with large brown medial spot; epandrium with yellow dorsal mottling.

Genitalia: (Figs 588-594 ) Epandrium with one posterodistal spine. Surstylus small and lobate with short apical spine and smaller ventromedial spine, widely spaced. Basiphallus with left lateral and dorsoapical surfaces sclerotised. Hypophallus small, narrow, curved anteriorly and with few apical hairs. Paraphallus narrow or slightly expanded distally. Distiphallus and mesophallus fused, narrow, cylindrical, dark, with small, pale apical chamber; gradual constriction at point of fusion between distiphallus and mesophallus. Ejaculatory apodeme dark and broad, with corners pronounced, width equal to length and stalk narrow.

Hosts.

Host genus use by L. brassicae is discussed in Lonsdale (2011), with the addition of Streptanthus in Eiseman and Lonsdale (2018).

Distribution.

Widespread in Nearctic, Oriental and Australasian Regions. Africa. Arabian Peninsula. Europe. Canary Islands. Japan.

Type material.

Holotype [brassicae]: USA. MO: St. Louis, 30.iv.1876 (1♀, USNM).

Holotype [ Liriomyza bulnesiae ]: Venezuela. Caracas, Botanical Gardens, caught on Bulnesia arborea Engl. ( Zygophyllaceae ), 5.xii.1958, K.A. Spencer (1♂, NHMUK). [Not examined]

Syntypes [ Liriomyza cruciferarum ]: Canary Islands. La Palma: Santa Cruz (2?, ZMHU) [Not examined]

Holotype [ Liriomyza hawaiiensis ]: USA. HI: Oahu, Honolulu, 1.i.1947, E.C. Zimmerman, ex. leaf of Cleone (1♀, BPBM).

Holotype [ Phytomyza mitis ]: Canada. MB: Aweme, 20.vii.1929, R.H. Handford, Type No. 3407 (1♂, CNC).

Additional material examined.

USA. MD: 4mi SW of Ashton, 29.v.1986, Malaise trap, G.F. and J.F. Hevel (1♂, USNM), Prince Georges Co., Beltsville, 18.ix.1969, R.E. Holmes (1♀, USNM), NC: Durham Co. , Durham, Pelham Road, 21.vi.2017, em. 8.vii.2017, T.S. Feldman, ex Cleome hassleriana , #CSE3909, CNC939820 (1♀, CNC), NY: Essex Co. , Upper Jay , by Ausable River , East Branch , 2.vi.2012, em. by 23.vi.2012, C.S. Eiseman, ex Cardamine diphylla (1♀, CNC), VA: Shenandoah Co., Bayse, 21.vii.1974, G.A. Foster (1♀, USNM), WV: Bluefield, 17.vi.1970, G. Steyskal (1♂, USNM). Also see Lonsdale (2011, 2017) .

Comments.

Liriomyza brassicae is difficult to differentiate from L. sativae externally and has been reared from many of the same plant species. Colour characters can be used to distinguish most individuals, but since there is some overlap in these features, only the male genitalia can be considered authoritative for identification. The dark, cylindrical, and medially constricted distiphallus is most diagnostic for this species.

While this polyphagous leaf-miner is nearly cosmopolitan, Liriomyza brassicae is not often considered a serious threat to agriculture due to its generally small population sizes (Spencer, 1973a). Several Californian morphotypes that are potentially separate host races or species are not treated here; see Lonsdale (2011) for details.

Figures

Figures 588 - 594. Liriomyza brassicae (Riley), male genitalia 588 ejaculatory apodeme 589 external genitalia, anterior (subepandrial sclerite shaded) 590 external genitalia, posterior 591 external genitalia, ventral 592 external genitalia, left lateral 593 phallus, left lateral 594 phallus, ventral. Originally published in Lonsdale (2011).