Cerodontha (Butomomyza) angulata (Loew)

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, Zootaxa 4479 (1), pp. 1-156 : 39-40

Cerodontha (Butomomyza) angulata (Loew)

( Figs. 22 , 124–125 )

Material examined. MASSACHUSETTS: Franklin Co., Northfield, 42.648774, -72.429433, 26.x.2015, em . 30.iii–3.v.2016, C.S. Eiseman, ex Carex , pupation external, #CSE2296, CNC654203–654211 (1♂ 8♀); same collection data, em. 17.iv.2016, pupation internal, #CSE2400, CNC654195 (1♀); 276 Old Wendell Rd. , 1.xi.2015, em. 3.v.2016, C.S. Eiseman, ex Carex , pupation external, #CSE2443, CNC654170 (1♀); 18.vii.2016, puparium 19.vii.2016, em. 4.viii.2016, C.S. Eiseman, ex Dichanthelium clandestinum , #CSE2842, CNC654169 (1♂); 23.vii.2016, em. 11.viii.2016, C.S. Eiseman, ex Scirpus hattorianus , #CSE2868, CNC659970 (1♀); Hampshire Co., Northampton , 42.366360, -72.671754 , 15.vi.2017, em. 6.vii.2017, C.S. Eiseman, ex Carex stipata , #CSE3899, CNC939710 (1♀); Pelham, Quarry St. , 4.vii.2013, em. 18.vii.2013, C.S. Eiseman, ex Dichanthelium clandestinum , #CSE713, CNC392665 (1♂); Pelham, Butter Hill Wildlife Sanctuary, 19.iv.2015, em. 8.v.2015, C.S. Eiseman, ex Luzula , #CSE1543, CNC564618 (1♀); Nantucket Co., Nantucket , 41.289665, -70.010519 , 30.vii.2017, em. 18.viii.2017, C.S. Eiseman, ex Carex crinita , #CSE4140, CNC939651 (1♂); Worcester Co., Charlton, Flint Rd. , 21.ix.2016, em. 25.ix.2016, C.S. Eiseman, ex Dichanthelium clandestinum , #CSE3010, CNC638884 (1♀); NORTH CAROLINA: Durham Co., Durham, Leigh Farm Park , 9.v.2017, em. 13.vi.2017, T.S. Feldman, ex Dichanthelium , #CSE3826, CNC939783 (1♂); 14.vi.2017, em. 3.vii.2017, T.S. Feldman, ex Dichanthelium , #CSE3891, CNC939773 (1♂); Pelham Road , 13.v.2017, em. 3–6.vi.2017, T.S. Feldman, ex Dichanthelium acuminatum ssp. acuminatum , #CSE3784, CNC939827–939829 (1♂ 2♀); Sandy Creek Park , 16.v.2017, em. 8.vi.2017, T.S. Feldman, ex Dichanthelium , #CSE3806, CNC939841 (1♀); Scotland Co., Laurinburg, St. Andrews University , 10.i.2017, em. 15.ii.2017, T.S. Feldman, ex Carex , #CSE3150, CNC939737 (1♀); 18.i.2017, em. 6.iii.2017, T.S. Feldman, ex Dichanthelium , #CSE3158, CNC939751 (1♂); WASHINGTON: Jefferson Co. , 10.x.2012, em. 4.v.2013, C.S. Eiseman, ex broad-leaved wetland Carex , #CSE412, CNC358502 (1♂); 11.x.2012, em. 20.v.2013, C.S. Eiseman, ex narrow-leaved upland Carex , #CSE528, CNC358501 (1♂).

Hosts. Cyperaceae : Carex * crinita Lam., C. * stipata Muhl. ex Willd. , Scirpus * hattorianus Makino ; * Juncaceae : Luzula DC.; * Poaceae : Dichanthelium acuminatum (Sw.) Gould & C. A. Clark , D. clandestinum (L.) Gould.

Leaf mine. ( Figs. 124–125 ) On Carex and Scirpus ( Fig. 125 ) the mine is whitish, and the larva moves up and down the leaf to form an irregular secondary blotch. Frass is deposited in a few large, black lumps. In our experience “long, narrow, yellowish” ( Spencer & Steyskal 1986) is not a good characterization of the mines of this species. The mine on Dichanthelium ( Fig. 124 ) begins with a dark, trumpet-shaped area along the midrib, and the larva initially mines toward the apex of the leaf. A single blackish patch of frass is deposited at the point where the larva reverses direction. The upper surface mines are greenish-white, with some reddish discolored patches (in some cases covering the majority of the mine surface). We have also found a single example of a lower surface mine that was white throughout (without reddish patches), beginning with a similar dark, trumpet-shaped area along the midrib, and likewise with all the frass in a patch where the larva turned around near the leaf tip. Mines on Luzula are whitish with reddish discolored patches, occupying most or all of the leaf when complete.

Puparium. ( Figs. 22 , 124 ) Oval, yellowish-brown to blackish-brown; glued with frass inside the mine or formed outside, frequently lightly attached to the leaf surface near the end of the mine ( Spencer & Steyskal 1986; Ellis 2016). In the Carex examples we collected in Washington, the puparium was formed within the mine (in one instance, the larva was accidentally ejected from the mine during collection, and it pupariated soon afterward). On Carex in Massachusetts, one puparium was formed within a mine and the rest were either found loosely attached near the bases of the leaves in the field or formed externally in rearing vials. In our experience, pupation has usually been outside the mine on the other host genera. On Dichanthelium , the puparium is sometimes found on the upper leaf surface a short distance from the end of the mine ( Fig. 124 ); in one instance it was directly on top of a split in the mine surface through which the larva had emerged, with a torn flap of the upper epidermis overlying part of the puparium; several of the North Carolina specimens pupated within the mine. The single puparium from Luzula was found loosely attached near the base of a mined leaf at the time of collection.

Distribution. Probably present in most states; Canada: AB, ON; Europe.

Comments. This species is known to mine many species of Carex (and rarely Scirpus sylvaticus L.) in Europe ( Ellis 2016), but together with that of Cerodontha scirpi (below), ours are apparently the first rearings of any species of Cerodontha (Butomomyza) in North America.

Additional rearing and study of this species is required as there appears to be some variation indicative of additional undescribed species, but the males examined appear to agree with the paralectotype illustrated in Spencer & Steyskal (1986). The phallus of one Carex -reared male (#CSE528) is somewhat paler, however, with the apical swellings of the mesophallus and distiphallus slightly less pronounced. The basal stalk-like section of the mesophallus of the male reared from broad-leaved wetland Carex (#CSE412) is also shorter, but this may be due to the fact that it died before adult development was complete.

Figures

FIGURE 22–29. Figure 22: Cerodontha (Butomomyza) angulata (Loew), empty puparium. Figure 23: Cerodontha (Butomomyza) sp. 1., empty puparia (left one parasitized by a braconid wasp). Figure 24: C. (Dizygomyza) edithae spec. nov., adult male. Figures 25–26: C. (D.) feldmani spec. nov.; 25: adult male; 26: empty puparium. Figure 27: C. (D.) morosa (Meigen), empty puparium. Figure 28: C. (Poemyza) incisa (Meigen), puparium. Figure 29: C. (P.) inconspicua (Malloch), puparia.

FIGURES 124–132. leaf mines; 124: Cerodontha (Butomomyza) angulata (Loew) in Dichanthelium clandestinum (puparium on leaf surface at lower left); 125: C. (B.) angulata in Carex sp.; 126: C. (C.) dorsalis (Loew) in Triticosecale sp.; 127: C. (Dizygomyza) edithae spec. nov. in Iris versicolor (puparium at left); 128: C. (D.) feldmani spec. nov. in Carex flaccosperma (puparium at far left; other dark spot is a dead larva); 129: C. (D.) cf. iraeos (Robineau-Desvoidy) in Iris cristata (brown puparium to right of black frass spot); 130: C. (D.) morosa (Meigen) in Carex leptonervia (puparium at right); 131: C. (Poemyza) incisa (Meigen) in Cinna arundinacea (transmitted light, with two puparia); 132: C. (P.) inconspicua (Malloch) in Elymus virginicus (transmitted light, with two puparia).