Cameraria arizonella (Braun, 1925) Eiseman & Davis, 2020

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 : 203-206

Cameraria arizonella (Braun, 1925) , new combination

( Figs. 5–14 )

Lithocolletis arizonella Braun 1925a: 148 . Phyllonorycter arizonella (Braun) — Davis 1983: 10.

Leaf mine. A flat, upper-surface blotch ( Figs. 5–6 ); see Comments for details.

Generic placement. Although Braun (1925a) did not refer to the flat larva, she gave characters to separate the adult from “its allies in the conglomeratella group.” This is a reference to Cameraria conglomeratella (Zeller) , an oak feeder, and leaves no doubt about the proper placement of the species. The mature leaf mine ( Fig. 6 ) is typical for Cameraria ; the distally dark-margined white markings on the forewings ( Figs. 7 , 13–14 ) and the pair of setae at the apex of the tegumen ( Fig. 9 ) confirm that arizonella belongs in this genus.

Host. Ericaceae : Arbutus arizonica (A. Gray) Sarg.

Distribution. USA: AZ.

Review. Braun (1925a) described this species from five specimens reared from upper-surface mines on Arbutus arizonica collected at White House Canyon in the Santa Rita Mountains of Arizona ( Fig. 13 ). There appear to be no further literature records of Cameraria arizonella . CSE reared six specimens from leaf mines on A. arizonica collected at Madera Canyon, Arizona (Santa Cruz Co.; likewise in the Santa Rita Mountains) on 14 March 2017 ( Figs. 5–7 ). The adults ( Figs. 7 , 14 ) emerged from 10 to 24 April, similar to Braun’s (1925a) emergence dates of 9 to 22 April.

Comments. It is worth noting here that Acrocercops arbutella Braun (Gracillariidae) , described immediately after Cameraria arizonella and from the same locality, also forms upper-surface blotch mines on Arbutus arizonica . Braun (1925a) did not clearly describe how the mines of the two species differ, but based on mines of Acrocercops arbutella collected in Arizona by CSE at Madera Canyon (Santa Cruz Co.) and Ramsey Canyon (Cochise Co.) and identified by the rearing of seven adults, we have noted several distinctions. The mine of C. arizonella begins with an initial narrow portion no more than a few mm long. Frass is plastered on the floor of the blotch, so that the mine appears clean and pale brown in reflected light. The finished mine has one or a few distinct creases, and the larva pupates within it. In contrast, the mine of A. arbutella begins with a long serpentine track with a central frass line. The upper epidermis is conspicuously stained with patches of brown frass, otherwise appearing whitish in reflected light. The finished mine is irregularly wrinkled but without distinct creases. Braun (1925a) did not state where the cocoon is formed, but contrary to the statement by Powell & Opler (2009) that pupation is within the mine, in our experience the larva always exits through a semicircular slit in the upper epidermis before spinning its cocoon.

Figures

FIGURES 5–7. Cameraria arizonella. 5: Aborted early leaf mine on Arbutus arizonica (eggshell at lower left); 6: Completed mine; 7: Reared adult.

FIGURES 8–10. Cameraria arizonella. 8: Phallus; 9: Male genitalia, ventral view; 10: Sternite 8.

FIGURES 11–14. Cameraria arizonella. 11: Female genitalia, ventral view; 12: Female genitalia, lateral view; 13: Holotype, reared by A.F. Braun (photo: J.D. Weintraub/ANSP Entomology); 14: Live adult.