Phyllonorycter celtisella (Chambers, 1871)

Eiseman, Charles S. & Davis, Donald R., 2020, Wrong side of the leaf: assigning some Lithocolletinae species (Lepidoptera: Gracillariidae) to their proper genera, Zootaxa 4751 (2), pp. 201-237 : 213-215

Phyllonorycter celtisella (Chambers, 1871) ( Figs. 30–32 )

L.[ithocolletis] celtisella Chambers 1871c: 129 .

Phyllonorycter celtisella (Chambers) — Davis 1983: 10.

Leaf mine. Chambers (1871c) stated that the mine ( Figs. 30–31 ) begins as a short, narrow, crooked line on the underside of the leaf, ending in a blotch that presents the same appearance on both sides of the leaf, i.e. slightly puckered along the center. Braun (1908) clarified that while the early linear portion is on the lower surface, the larva “then cuts through the parenchyma to the upper side, where the mine broadens into an elongate blotch, made tentlike by a longitudinal ridge in each epidermis.” The larva then eats “the entire parenchyma, leaving merely the dark discolored cuticles of the leaf.”

Hosts. Cannabaceae : Celtis laevigata Willd. , C. occidentalis L.

Distribution. Canada: ON; USA: CT, IA, IL, KY, MA, NC, OH, OK, TX.

Review. Chambers (1871c) described this species from specimens reared from Celtis occidentalis in Kentucky. Braun (1908) stated that the range of Phyllonorycter celtisella “is wide, and probably coincides with that of its food plant.” Specific records include Texas ( Frey & Boll 1876, as Lithocolletis pusillifoliella ), Ohio ( Ely 1917), Ontario ( Yoshimoto 1977), Illinois ( Godfrey et al. 1987), and Connecticut ( Maier & Davis 1989).

CSE has reared this species from a C. occidentalis mine collected in the Loess Hills, Monona Co., Iowa ( Fig. 32 ), and has examined mines from the same host collected by M.W. Palmer in Payne Co., Oklahoma, and from C. laevigata collected by T.S. Feldman in Scotland Co., North Carolina. S. Whitebread (in litt.) reports having reared P. celtisella from mines collected in Massachusetts (Hingham, Plymouth Co.), and notes that adult emergence may be from either the upper or the lower leaf surface.

Comments. In Connecticut, Maier & Davis (1989) reared adults of Phyllonorycter celtisella from mines collected on 13 June, 17 August, 23 September, and 19 October, but they did not report the emergence dates. A mine CSE collected in Ottawa, Ontario on 11 July yielded an adult on 16 July, and the Iowa and Massachusetts specimens emerged in spring from mines collected on 17 September and 27 October, respectively. Thus, in the northern part of its range, occupied mines of P. celtisella can be found in every month from June to October; two generations have been confirmed, but there are possibly more. We are not aware of earlier dates for larvae in southern states, but the Texas specimen was caught in Dallas in mid-April ( Frey & Boll 1876). In Illinois, Godfrey et al. (1987) did not cite any observations of larvae but listed adult collection dates ranging from 30 April to 28 August.

Phyllonorycter celtifoliella (Chambers) also feeds on Celtis in eastern North America, but it makes a typical underside tentiform mine. This species is much less common than P. celtisella according to Chambers (1871c) and Braun (1908), although the reverse is true in the vicinity of Charleston, Coles Co., Illinois (T. Harrison in litt.).

Figures

FIGURES 30–32. Phyllonorycter celtisella. 30: Lower surface of leaf mine on Celtis occidentalis (note short initial portion formed on lower surface at upper right); 31: Upper surface of the same mine (note longitudinal crease in blotch portion, with protruding pupal exuviae); 32: Reared adult.