Phytomyza aconiti Hendel
Creators: name: Eiseman, Charles S.
name: Lonsdale, Owen
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Agromyzidae
Phytomyza
Phytomyza aconiti

description: Phytomyza aconiti Hendel
(Fig. 171)
Material examined. COLORADO: Park Co., High Creek Fen, off of Rte. 185, 13.vii.2015, em. 29.vii– 1.viii.2015, C.S. Eiseman, ex. Aconitum columbianum, #CSE1891, CNC564713–564723 (4♂ 7♀); MASSACHUSETTS: Hampshire Co., Pelham, 88 Arnold Rd., 3.ix.2012, em. 28.ix.2012, C.S. Eiseman, ex Delphinium, #CSE108 (3♂ 2♀).
Hosts. Ranunculaceae: Aconitum sp. (Spencer 1969), A. * columbianum Nutt., Delphinium x cultorum Voss (Frick 1959).
Leaf mine. (Fig. 171) Several larvae feeding together (up to five or perhaps more), forming a greenish blotch, which later turns whitish to pale brown and disfigures the leaf. Frass is in distinct black grains, scattered abundantly throughout.
Puparium. Brown; formed outside the mine.
Distribution. USA: *CO, *MA, NY, OH, PA; Canada: QC; Europe.
Phytomyza actaeivora spec. nov.
(Figs. 35, 37, 172, 303–308)
Holotype. MASSACHUSETTS: Franklin Co., Northfield, 42.649095, -72.429338, 10.x.2015, em. 4.iv– 4.vi.2016, C.S. Eiseman, ex Actaea pachypoda, #CSE2318, CNC654100 (1♂).
Paratypes. MASSACHUSETTS: same collection as holotype, CNC 654101–654107 (7♂ 1♀).
Etymology. The specific epithet refers to the host plant, Actaea L.
Host. Ranunculaceae: Actaea pachypoda Elliott. We have found larvae forming similar leaf mines on A. racemosa L. and A. rubra (Aiton) Willd.
Leaf mine. (Fig. 172) A whitish upper-surface blotch with conspicuous primary and secondary feeding lines, containing several larvae. The blackish frass is in scattered small particles and wavy threads. Larvae exit through slits in the lower epidermis.
Puparium. (Fig. 37) Whitish to pale yellow, protruding from the exit slit or loosely attached to the lower leaf surface adjacent to the exit slit.
Distribution. USA: MA; we have seen similar leaf mines in NY, OH, and VT, and Spencer (1969) reported one from QC.
Adult description. Wing length 2.3–2.5mm (♂), 2.5mm (♀). Eye height divided by gena height: 5.4–7.3. First flagellomere slightly enlarged, slightly longer than high, apically rounded; except at base, covered with hairs as long as width of arista base. Arista pubescent. Notum pruinose. Orbital plate not well defined. Vein dm-cu absent.
Chaetotaxy: Two ors (posterior seta 2/3–4/5 length anterior), two ori (anterior seta thinner and ½–2/3 length posterior). Ocellar seta subequal to anterior ori. Postvertical slightly longer than anterior ors. Four strong dorsocentral setae that slightly decrease in length anteriorly. Acrostichal setulae in usually four but sometimes up to six scattered rows.
Coloration: (Fig. 35) Setae dark brown. Head yellow with dirty white tint that is darker on frontal vitta and face; pedicel and scape light brown to yellowish, first flagellomere dark brown; orbital plate with minute light brownish spots around base of setae and setulae; posterior margin of vertex and posterolateral corner of frons to base of inner vertical seta dark brown, with spot extending as paler stripe (usually very light brown) to base of posterior ors; ocellar spot slightly larger than tubercle, subquadrate with corners rounded and anteromedial margin concave. Body with light brownish pruinosity that is only pronounced on thorax, where it is almost coppery; there are large, irregular and heavier bluish patches medially on scutum. Base color of thorax brown to dark brown, with postpronotum, notopleuron and supra-alar spot paler. Wing veins yellow, becoming white to base. Calypter white with hairs light brown. Haltere white. Legs dark brown with apices of femora light yellow, with spot as long as wide, and tibiae and tarsi yellow to light yellow with apical tarsomeres light brown. Abdomen dark brown with lateral margin of tergites narrowly yellow.
Genitalia: (Figs. 303–308) Surstylus fused to epandrium, weakly sclerotized except for setose margin; epandrium with flat marginal lobes ventrolateral to cerci. Hypandrium stout and rounded with long apical apodeme. Postgonite simple with one medial seta and two subapical sockets. Phallophorus dorsally fused to right sclerite of basiphallus. Basiphallus composed of two narrow plates, apically darker, with base of left sclerite wrapping around venter of shaft. Hypophallus with one pair of dark lateral bar-like arms with irregular margins that meet ventrally via flat transverse plate; ventromedial surface with stout irregular tubule that is produced as narrow flagellum with dark base. Paraphallus darker and shorter than lateral arm of hypophallus; anteriorly converging and fused to ventromedial surface of mesophallus. Mesophallus as long as sclerite of hypophallus, with one pair of small, flat lateral plates emerging from dorsum; dark and cylindrical with distal half abruptly expanded and rounded to support distiphallus. Distiphallus divided into one pair of narrow tubules slightly longer than basiphallus; strongly separated at base with dark “elbow”, tubules paler and slightly curved and convergent apically. Ejaculatory apodeme well-developed; sperm pump with transverse sclerite with thickened lateral margins.
Comments. The adult of Phytomyza actaeivora is dark and brownish pruinose with the frons mostly yellowish (notably excluding a dark stripe to the posterior ors on the frons), the pedicel and scape are yellowish and the first flagellomere dark brown, the apices of the femora are distinctly light yellow, the lateral margin of the abdominal tergites are yellow and the wing veins are yellow. Internally, the distal apodeme of the hypandrium is unusual (Fig. 305), the structure of the hypophallus (sclerited section and medial tubule) is unique, and the lateral processes of the mesophallus and the slender distiphallus tubules that are abruptly angled basally are highly distinctive (Figs. 307, 308). The first flagellomere is also covered with long hairs, which will allow it to be keyed to P. ceanothi Spencer [specimens not available for examination] in Spencer & Steyskal (1986), but in this species from Kansas, there is just one ori, the orbital plate is entirely yellow, the margin of the calypter is dark brown, the wing is only 1.3–1.8mm, the paraphallus is absent, and the tubules of the distiphallus are fused and pointed distally.
The leaf mine of Phytomyza actaeivora is similar to that of the European P. actaeae Hendel, as noted by Spencer (1969) in his discussion of an unidentified mine on Actaea rubra found in Quebec. Mines on A. rubra range from whitish to brownish, and on this host we have found larvae in late June and early July, suggesting P. actaeivora is at least bivoltine (if the A. rubra feeder is indeed conspecific).
description: Published as part of Eiseman, Charles S. & Lonsdale, Owen, 2018, New state and host records for Agromyzidae (Diptera) in the United States, with the description of thirty new species, pp. 1-156 in Zootaxa 4479 (1) on pages 64-65, DOI: 10.11646/zootaxa.4479.1.1, http://zenodo.org/record/1452913