Liriomyza arctii Spencer

Liriomyza arctii Spencer

(Fig. 133)

Material examined. CONNECTICUT: Litchfield Co., Canaan, 21.vii.2015, em. 6.viii.2015, C. Vispo, ex Heliopsis helianthoides, #CSE2167, CNC564650, CNC564651 (2♀); MASSACHUSETTS: Franklin Co., Northfield, 276 Old Wendell Rd., 1.vi.2016, em. 24.vi.2016, C.S. Eiseman, ex Arctium minus, #CSE2628, CNC654199 (1♀); Connecticut River boat ramp, 24.ix.2016, em. 20.iv.2017, C.S. Eiseman, ex Bidens cernua, #CSE3528, CNC939721 (1♂); OHIO: Delaware Co., Sunbury, Monkey Hollow Rd., 1.viii.2016, em. 13.viii.2016, C.S. Eiseman, ex Verbesina alternifolia, #CSE2879, CNC659969 (1♂); WISCONSIN: Buffalo Co., Alma, S1287 State Road 88, 17.vii.2015, em. 6.viii.2015, C.S. Eiseman, ex Heliopsis helianthoides, #CSE1969, CNC564623 (1♂).

Hosts. Asteraceae: Arctium lappa L. (Scheffer & Lonsdale 2018), A. minus Bernh., * Bidens cernua L., * Heliopsis helianthoides (L.) Sweet, * Verbesina alternifolia (L.) Britton ex Kearney.

Leaf mine. (Fig. 133) On Arctium, a “[n]arrow, whitish, linear mine, with frass initially greenish-diffused, later in more distinct black strips” (Spencer 1969). The mines we collected on Arctium matched this description, but those on Heliopsis and Verbesina had greenish to blackish, diffuse frass deposits throughout their length, without any distinct strips. In the single mine found on Bidens, the frass was mostly diffuse but with intermittent, more or less distinct strips. The mine on Verbesina was 1.5 mm wide at the end.

Puparium. Dark brown, formed outside the mine (Spencer 1969); our puparia varied from yellow to orange to medium brown.

Distribution. USA: *CT, *MA, MN, NY (Scheffer & Lonsdale 2018), *OH, WI; Canada: ON. The record of “WN” (Lonsdale 2017) refers to WI (Spencer & Steyskal 1986).

Comments. This apparently native fly has been reared repeatedly from Arctium (Carduoideae), an Old World genus introduced to North America. Bidens, Heliopsis, and Verbesina (Asteroideae) are the first native host records. The use of hosts in two different subfamilies presents the possibility that Liriomyza arctii may feed on a wide variety of asteraceous plants. As far as is known, every other Nearctic Asteraceae-feeding Liriomyza is either restricted to hosts in one subfamily or has hosts in at least one other order.