Stigmella vandrieli

Diagnostic description: 

Diagnosis. A fasciate species with very distinct androconial scales and edged scape, only to be confused with S. kurokoi, which has a dark frontal tuft in contrast to the orange one in vandrieli. Male genitalia characterized by the vesica with more than two complete coils. Female only separated from other fasciate species (kao, kurokoi, castanopsiella, clisotophora) by the complicate genitalia.

Morphology: 

Description. Male. Forewing length 2.0-2.3 mm (n=3), wingspan 4.9-5.0 mm. Head: frontal tuft orange; collar lead-grey; scape silvery white, posteriorly and distally edged with lead-grey to black; flagellum grey-brown. Antennae with 30-31 segments (n=3).
Thorax shining lead-grey. Forewings basal third shining lead-grey, followed by dark brown band of 1/4 wing-length, a shining silvery fascia at 2/3, constricted in middle or broken, dorsally enlarged; wingtip dark brown, with distinct cilia-line, terminal cilia silvery grey; underside dark brown with blue green gloss. Hindwing costa with long spatulate, dark brown androconial scales; these almost as long as hindwing width. Upperside of hindwing with dark brown lamellar scales, slightly extending into dorsal fringe, about 1/5 cilia length. Underside grey-brown. Abdomen brown-grey, ventrally grey; anal tufts absent.
Female. Forewing length 2.2-2.4 mm (n=2), wingspan 5.4-5.6 mm. Antennae with 22 segments (n=1). Very similar to male, but forewing underside grey-brown with blue-green gloss, hindwing grey, without special scales.
Male genitalia. Capsule length 205-230 µm (n=3). Tegumen slightly arched. Vinculum narrow, with deep anterior excavation. Uncus bilobed, notch equal to width of individual lobes. Gnathos with posterior processes basally close, diverging posteriorly, pointed; anteriorly with small anterior processes. Valva length 130-140 µm (n=3), almost triangular; with short distal process and a more ventral setose lobe; transtilla wide, sublateral processes about half its length. Aedeagus 475-500 µm long (n=3), basally bulbous, 210-215 µm wide, more than twice as long as capsule; vesica coiled, with 2.5 tot 3 complete coils, with a narrow band of numerous pointed cornuti: small in basal part , larger ones near tip; manica conspicuous, enveloping only part of distal half of aedeagus.
Female genitalia. T8 rounded, with a group of scales and 4-5 setae centrally and a pair of lateral setose lobes. All apophyses relatively long and narrow. Bursa complex, structure not completely understood, ca. 1050-1110 μm long. Ductus bursae long (more than half bursa length) and narrow, with a complete coil in middle, leading towards a globular sac, which is either the bursa or accessory sac; from the ductus a sclerotized spinose structure runs into the sac and makes 2 turns and ends spirally. It seems as if the ductus spermathecae is part of this structure. The whole structure seems to fit the male coiled vesica perfectly.

Associations: 

Hostplant. Cyclobalanopsis glaucoides (=Quercus (Cyclobalanopsis) glauca ssp. schottkyana), an evergreen cupuliferous tree with serrate, coriaceous leaves. Mines collected on leaves of 50-125 mm long.
Leafmines. Egg on leaf upperside, position indifferent, but not infrequently on a lateral vein. Mine a much contorted gallery, first filled with black frass, later with dispersed black frass, leaving narrow clear margins.
Larva. Pale greyish white in mine, pale yellow outside; head pale, with dark brown caudal extensions and eye spots; ganglia not visible in mine, but distinct outside; feeds with dorsum upwards.

Distribution: 

Yunnan.

Life cycle: 

Life history. Larvae found in October, adults reared in October-November.

Citation: 

This taxonomic description is based on Van Nieukerken (2000).

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith