Agromyza apfelbecki Strobl, 1902

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

Agromyza apfelbecki Strobl

Figs 152-155

Agromyza abiens var. Agromyza abiens Apfelbecki Strobl, 1902: 504.

Agromyza andalusiaca Strobl, 1906: 380. Hendel 1920 [synonymy].

Agromyza Apfelbecki . Hendel 1920: 117. Hendel 1931: 107.

Agromyza apfelbecki . Spencer 1966 c: 172; Papp 1984: 264; Spencer 1990: 253.

Description.

Wing length 4.0-4.1 mm (♂), 4.4-4.8 mm (♀). Length of ultimate section of vein M4 divided by penultimate section: 0.4-0.7. Eye height divided by gena height: 2.1-2.4. Ocellar triangle small and rounded. First flagellomere small and rounded; without apical tuft of pale hairs. Fronto-orbital plate slightly projecting and parafacial strongly projecting, partially to strongly continuing under eye as cheek. Wing slightly pointed apically with apex between M1 and R4+5. Thorax with light to dense grey pruinosity.

Chaetotaxy: Three to seven ori (two in Spanish female); two ors. Six or seven dorsocentrals, two or three presutural, decreasing in size anteriorly. Mid tibia without posteromedial setae.

Colouration: Body mostly dark brown. Head yellow with back of head, occiput, clypeus, mentum and ventral margin of gena dark brown, distal 2/3 of first flagellomere brownish, venter of face light brown and frons slightly darker anteriorly. Knees yellowish orange; tibiae and tarsi paler than femora with tibiae slightly darker medially. Scutum with nearly imperceptible metallic green shine in VA female. Calypter margin and hairs white to dark brown. Halter white, rarely with small lateral spot and ventral margin of knob brown (VA female). Abdomen dark brown with indistinct (VA) or strong coating of grey pruinosity, except on brownish orange male terminalia (sometimes with dark dorsomedial spot on epandrium). European specimens often with fronto-orbital plate, face, apex of palpus, parafacial and ring under eye mostly dark, tibiae often yellowish or more orange on distal 1/3, and epistoma usually larger.

Genitalia: (Figs 152-155 ) Epandrium relatively broad and shallow, with suture between it and surstylus barely evident. Surstylus slightly curved anteriorly and with numerous small, pointed, tubercle-like setae along inner-basal/medial surface. Phallophorus tapered distally and partially fused to flat, pale sclerites of basiphallus, which are weakest and irregular along dorsal margin, with right sclerite partially separated from darker, curved apical section. Hypophallus sac-like and membranous with partial sclerotisation along anteromedial surface. Distiphallus nearly cylindrical with irregularly sclerotised margins not entirely meeting ventrally; twisted past midpoint. Ejaculatory apodeme minute.

Hosts.

Asteraceae - Carduus , Cirsium , Cynara ( Spencer 1990).

Distribution.

USA: VA*. France, Italy, Malta, Germany, Spain, Croatia ( Papp and Černý 2015). Turkey. Chile (Valparaiso, La Cruz; introduced) and Argentina ( Valladares 1998; Çöl et al. 2006).

Type material.

Syntypes [ Apfelbecki ]: Yugoslavia. Zadar (♂♀, coll. Strobl). [Not examined]

Syntypes [ Agromyza andalusiaca ]: Spain. "Southern Spain" [= Algreciras?] (?, coll. Strobl). [Not examined]

Material examined.

France. Perpignan , 10.x.1959, mine Cynara carduuculus, em. 24.v.1959, K.A. Spencer, CNC352745 (1♂ [with puparium], CNC) . Germany [?]. "Agrom. Apfelbecki Str., det. Hendel " (1♀, USNM) . Spain. Barcelona , “prat”, 27.iii.1960, K.A. Spencer (1♀, USNM), CNC352746 (1♀, CNC), En Alcachofe , La Cruz , Valpo, Nac. 5.ix.1959, N. Hichins (5♂ 2♀ 1?, USNM) . USA. VA: Fairfax Co., Turkey Run Park , 0.3 km W mouth Turkey Run, 38°58'N, 77°09.6'W, Malaise trap, 29.iii-25.iv.2007, D.R. Smith (1♀, USNM) .

Comments.

While difficult to differentiate from a number of Palaearctic taxa, Agromyza apfelbecki is quite distinct from Nearctic Agromyza because it is exceptionally large (wing length at least 4.0 mm), there are numerous dorsocentrals (at least six), the epistoma is large and pronounced, the head is predominantly pale (including the palpus and face) and the halter is sometimes maculated. Agromyza apfelbecki is one of only three Agromyza known to feed on Asteraceae , and is distributed primarily around the Mediterranean where it often occurs on globe artichoke (Spencer, 1990).

The above Virginia record is the first known occurrence of this species in the Nearctic, where it was likely introduced accidentally on its host plant. As discussed by Dempewolf (2004), Agromyza apfelbecki can be a Plantago major pest on artichoke if populations become large enough, particularly to younger plants; the damage caused by larval feeding can vary significantly between years (Spencer 1973), possibly due to climatic conditions, as frost can severely increase mortality among larvae ( Ricchello 1928).

Figures

Figures 152 - 155. Agromyza apfelbecki Strobl, male genitalia 152 external components, ventral 153 hypandrium and postgonite, ventral 154 hypandrial complex, right lateral 155 phallus, ventral.