Liriomyza euphorbivora Eiseman & Lonsdale, 2021

Eiseman, Charles S., Lonsdale, Owen, Linden, John Van Der, Feldman, Tracy S. & Palmer, Michael W., 2021, Thirteen new species of Agromyzidae (Diptera) from the United States, with new host and distribution records for 32 additional species, Zootaxa 4931 (1), pp. 1-68 : 27

Liriomyza euphorbivora Eiseman & Lonsdale , spec. nov.

( Figs. 40–43 , 75 , 140–143 )

Holotype. USA. OKLAHOMA: Payne Co., Marena , 36.072618°, -97.247242°, 29.v.2018, em. 14.vi.2018, M.W. Palmer, ex Euphorbia marginata , # CSE4617 , CNC1144138 (1♁).

Etymology. The specific epithet refers to the host plant genus, Euphorbia L.

Host. Euphorbiaceae : Euphorbia marginata Pursh.

Leaf mine. ( Fig. 75 ) The single collected mine was a whitish (partially greenish), roughly circular blotch on the upper leaf surface, centered on the midrib, 7 mm across when complete, with frass in a few small, dark grains and lumps. A photo taken of the lower leaf surface at the time of collection shows what appears to be a 0.2-mm wide, epidermal linear mine, but this does not appear to be contiguous with the mine that contained the fly larva and we believe it is unrelated. It is not discernible in the preserved leaf.

Puparium. Yellow; formed outside the mine.

Phenology and voltinism. The only known specimen was collected as a larva in late May, emerging as an adult in mid-June.

Distribution. USA: OK.

Adult description. Wing length 1.5 mm (♁). Female unknown. Length of ultimate section of vein M 4 divided by penultimate section: 2.8. Eye height divided by gena height: 3.0. First flagellomere small, rounded. Thorax subshining.

Chaetotaxy: Two ori, two ors; subequal to ocellar and postvertical setae. Four dorsocentral setae, only first seta long, with second seta ⅖ length. Five rows of acrostichal setulae.

Coloration: ( Figs. 40–43 ) Setae dark brownish-black. Head yellow with ocellar spot dark brown; posterolateral corner of frons dark brown nearly to base of outer vertical, paler brown to base of inner vertical; back of head and clypeus brown. Scutum dark brown with wide, complete lateral yellow stripe on scutum (reaching base of posterior supra-alar and intra-alar) that continues along posterior margin as narrow line along scutellum. Mediotergite dark brown; anatergite brown with posterodorsal corner yellow; katatergite yellow with posteroventral corner brown. Pleuron yellow in base color; anepisternum with wide clavate anteroventral stripe (wider anteriorly) and narrow posteromedial line along suture; anepimeron mottled brown; katepisternum brown below level of seta; meron mostly brown. Scutellum dark anterolaterally. Legs yellow with basal half of fore coxa dark brown, mid coxa basally brownish and hind coxa mottled brown; base of femora narrowly brown (reduced ventrally); tibiae brown with base of fore and mid tibiae yellow, fore tibia yellower and hind tibia darker; tarsi brown. Abdomen brown dorsally, stripe narrowing posteriorly to tergite 5; epandrium brown. Calypter margin yellow with grey tint, hairs greyish-brown.

Genitalia: ( Figs. 140–143 ) Epandrium not fused to surstylus, with one spine. Surstylus with two apical spines. Phallophorus with venter much reduced, short. Basiphallus sclerotized along dorsal and left lateral surface with extension on left distal margin below paraphallus. Paraphallus simple, narrow. Hypophallus with small rod-shaped sclerite with apical hairs. Ejaculatory duct swollen and pigmented apically. Mesophallus slightly shorter than distiphallus, subcylindrical, fused to distiphallus dorsally, with slight ventral carina along suture. Distiphallus slightly wider than mesophallus, distal half shallow and cup-shaped, enclosing one pair of short processes, angled dorsally; basal half slightly narrower, sides parallel in ventral view, tapering basally in lateral view. Ejaculatory apodeme large and well-developed with broad blade; sperm pump with broad sclerotized cup-like venter.

Comments. This is the second Liriomyza to be reared from Euphorbia in North America, after L. euphorbiella Eiseman & Lonsdale. That species is likewise known only from Payne Co., Oklahoma, but it was reared from E. heterophylla var. cyathophora (Murray) Griseb. rather than E. marginata , and its mine begins with a distinct linear portion and does not cross the midrib. Mines on E. marginata similar to that of L. euphorbivora have been photographed in Ontario ( Mews 2019b), and the aborted mine on E. cf. brachycera Engelm. in Colorado noted by Eiseman & Lonsdale (2019) could conceivably have represented this species. TSF has found largely linear Liriomyza mines on E. curtisii Engelm. in North Carolina, but so far adults have not been reared from these.

Worldwide, 12 Liriomyza species have now been reported from Euphorbia , including three listed by Benavent- Corai et al. (2005) that were omitted without explanation from the review of Euphorbia -feeding Agromyzidae by Martinez & Sobhian (2000). Of these three, L. congesta (Becker) normally feeds on Fabaceae , and L. sonchi Hendel on Asteraceae , so these records seem likely to be erroneous (both are derived from a paper on parasitoids of Agromyzidae in Valencia, published in 1987). The record of the highly polyphagous L. sativae Blanchard appears plausible, however, apart from its being poorly documented (the cited source, Martinez (1993), is apparently a simple list of host genera, and is a publication we have been unable to obtain after multiple attempts; Martinez & Sobhian (2000) explicitly stated that L. sativae is “not yet recorded on Euphorbia ”). Possibly this record refers to McClanahan (1975), who caged a population of L. sativae with E. pulcherrima Willd. ex Klotzsch and observed light mining but no puparium formation. Whether the unidentified Nearctic mines noted above represent any of these 12 species remains to be seen, but to aid in the identification of Liriomyza specimens reared from Euphorbia , a modified version of the key by Martinez & Sobhian (2000) is presented below with L. euphorbiella , L. euphorbivora , and L. sativae added, and supplemented with data from Ellis (2020).

Figures

FIGURES 40–47. Figures 40–43: Liriomyza euphorbivora Eiseman & Lonsdale, spec. nov., holotype; 40: dorsal; 41: head; 42: lateral; 43: habitus. Figures 44–47: L. hypopolymnia Eiseman & Lonsdale, spec. nov.; 44: paratype, dorsal; 45: same, head; 46: same, lateral; 47: puparia.

FIGURES 73–86. Mines of Phytomyzinae on host plants: 73: Liriomyza blechi Spencer on Ruellia carolinensis; 74: Liriomyza cf. cracentis Lonsdale on Ageratina altissima; 75: L. euphorbivora Eiseman & Lonsdale, spec. nov. on Euphorbia marginata; 76: L. hypopolymnia Eiseman & Lonsdale, spec. nov. on Polymnia canadensis, upper surface; 77: same, lower surface; 78: L. orilliensis on Nabalus sp.; 79: L. cf. taraxaci Hering on Krigia virginica; 80: L. trifolii (Burgess) on Mecardonia acuminata; 81: Phytomyza cf. aesculi Eiseman & Lonsdale on Aesculus flava; 82: P. flavilonicera Eiseman & Lonsdale, spec. nov. on Lonicera sempervirens; 83: same; 84: P. notopleuralis Spencer on Cornus sericea; 85: P. thermarum (Griffiths) on Erigeron pulchellus; 86: P. triostevena Eiseman & Lonsdale, spec. nov. on Triosteum sp.

FIGURES 140–143. Liriomyza euphorbivora Eiseman & Lonsdale, spec. nov., male genitalia; 140: external components, ventral; 141: ejaculatory apodeme; 142: phallus, ventral; 143: same, left lateral.