Ophiomyia kwansonis Sasakawa

Material examined. ONTARIO: Ottawa, 695 Malibu Tr., 10.vii.2021, em. 2–4.viii.2021, O. Lonsdale, ex ornamental Hemerocallis, CNC1905434, CNC1905435 (1♂ 1♀), 21.vii.2021, em. 12.viii.2021, CNC1905432, CNC1905433 (2♂).

Photographed mines. DISTRICT OF COLUMBIA: 38.941969, −76.989364, 16.vii.2022, C. Seltzer, mines on Hemerocallis fulva (iNat 122893379); IOWA: Linn Co., Mt. Vernon, 41.918168, −91.412591, 19.ix.2019, I. Winkler, mines on Hemerocallis (iNat 40142448); MAINE: York Co., Wells, 43.3177, −70.649863, 5.vii.2020, W. Sweet, mines on Hemerocallis (iNat 52017284); MINNESOTA: Hennepin Co., Edina, 44.898279, −93.363009, 17.vii.2020, M. Zappa, mines on Hemerocallis fulva (iNat 53427056); NEBRASKA: Douglas Co., viii.2020, dvdkssrw, mines on Hemerocallis (iNat 67782014); NEW JERSEY: Morris Co., Chester Twp., 40.778965, −74.721274, 5.vii.2020, S. Rall, mine on Hemerocallis fulva (iNat 52147248); NORTH DAKOTA: Burleigh Co., Bismarck, 46.813928, −100.790663, 26.ix.2020, megnd, mine on Hemerocallis (iNat 60901873); OREGON: Multnomah Co., Portland, 29.vii.2015, M.W. Palmer, mines on Hemerocallis (BG 1111821); RHODE ISLAND: Bristol Co., 41.695188, −71.259471, 24.vii.2021, chickenparmesan24, mine on Hemerocallis (iNat 88459700); VERMONT: Bennington Co., Rupert, 43.274368, −73.172933, 24.vii.2021, N. Sharp, mines on Hemerocallis fulva (iNat 88371120); WASHINGTON: Thurston Co., Olympia, 47.07716, −122.94313, 17.vii.2024, M.W. Palmer, mines on Hemerocallis (iNat 229925628); BRITISH COLUMBIA: Greater Vancouver, 49.220827, −123.025071, 8.vii.2023, S.B. Robeson, mine on Hemerocallis (iNat 172054363); NEW BRUNSWICK: Westmorland Co., Sackville, 45.900079, −64.365159, 16.vii.2022, J. Klymko, mine with puparium on Hemerocallis (iNat 126471381); NOVA SCOTIA: Halifax, Dalhousie University, 44.637225, −63.58862, 29.ix.2023, loireegger, mine on Hemerocallis (iNat 185452927); ONTARIO: York Co., Markham, Marsnow Dr., 43.830692, −79.411483, 29.vi.2020, H. Mews, mine on Hemerocallis (iNat 51626033); 43.830617, −79.411475, 29.vi.2020, H. Mews, mines on Hemerocallis (iNat 51626077); PRINCE EDWARD ISLAND: Queens Co., Bedford Parish, 46.267788, −63.025993, 16.vii.2022, R. W. Harding, mine with puparium on Hemerocallis fulva (iNat 126524588); QUEBEC: Montreal, 45.5042, −73.57747, 26.ix.2023, Z. Cai, mines on Hemerocallis (iNat 185058619).

Host. Asphodelaceae: Hemerocallis fulva (L.) L. (Williams & Steck 2014).

Leaf mine. (Williams & Steck 2014: Figs. 4–5) Silvery-whitish; long, narrowly linear, sometimes becoming irregular or spiral-shaped; frass often not evident, but sometimes visible as fine, dark grains and short strips. Williams & Steck (2014) note that “often larvae cross to the lower surface and continue to feed until they mature.” Location of pupation varies, but mature larvae often appear to occur towards the paler, concealed base of the leaf or the dorsal root surface.

Puparium. Pale brownish, not strongly segmented; posterior spiracles dark brown with pores in one or two irregular rows in a shallow arc. Pupation internal with anterior spiracles protruding through leaf surface (Williams & Steck 2014: Fig. 6).

Phenology and voltinism. In North America, Williams & Steck (2014) note “Multiple overlapping generations” annually, and while adults are present throughout the growing season, more concentrated adult emergence occurs in June and August.

Distribution. USA: [AL, AR, CA, CT, DC, DE], FL, [GA, IA, IL, IN, KS, KY, LA, MA], MD, [ME, MI, MN, MO], MS, [NC, ND, NE, NH, NJ, NY, OH, OR, OK], PA, [RI, SC], TN, [TX], VA, [VT, WA, WI, WV]; * Canada: [BC, NB], ON, [PE, QC]; Japan; Taiwan; Slovenia (Williams & Steck 2014). Apart from our Ontario material, adult specimens have only been reported from Florida and Maryland; other USA records not in brackets are based on examined larvae and puparia.

Comments. These are the first specimens of Ophiomyia kwansonis, the daylily leafminer, from Canada. Its occurrence in Canada is unsurprising considering the speed at which this Japanese species has spread throughout the United States following its likely accidental introduction via the trade of its ornamental host, perhaps as early as 2006 (Williams & Steck 2014). Additional Canadian records of leaf mines are documented on iNaturalist, with two observations in June 2020 near Toronto being the earliest. The first known example for each province is listed above under Photographed mines (as well as the first photographed mine for each US state not listed by Williams & Steck (2014)), with observations in 2022 from New Brunswick and Prince Edward Island, and in 2023 from British Columbia, Quebec, and Nova Scotia.

One male specimen of Opius (Braconidae) was reared from a larva collected at the same locality as the reared flies (coll. 10.vii.2021, em. 8.viii.2021, CNC1905436). Other reared parasitoid Hymenoptera of this invasive species are mentioned in Williams & Steck (2014), but these specimens were not identified at the time of publication. The specimen was identified by J. Fernandez-Triana (CNC), who noted that Opius is a large genus in need of global revision, with 180 described species in North America alone. No Opius has been reared from Ophiomyia kwansonis previously, so there is the possibility that the association is new.