Stigmella trojana

Diagnostic description: 

Diagnosis. Males somewhat resemble S. basiguttella and S. samiatella, but have usually a paler dorsum and a more mottled appearance; also the spatulate scales along hindwing costa (to be seen from underside!) distinguish trojana. Females can be confused with other black-headed species, particularly S. atricapitella and S. zangherii.
Male genitalia separated from similar S. bicuspidata by smoothly rounded inner lobe of valva, from very similar S. dorsiguttella by shorter inner lobe, not reaching tip of distal process. Female genitalia characterised by the arrangement of the spines in the globular accessory sac on two bulbous lobes.

Morphology: 

Description. Male. Forewing length 2.1-2.3 mm, wingspan 4.4-5.0 mm. Head: frontal tuft fuscous to black, occasionally a few yellow scales; collar white. Scape white. Antenna grey brown, 2/3 of forewing length, with 34-36 segments. Thorax and forewing dark grey brown, hardly shining at tip, along dorsum usually paler, almost white; terminal cilia concolorous, slightly paler at tip; underside dark grey brown, with basal elongate yellowish grey, pale spot of indistinct androconial scales. Hindwing pale grey, along dorsum in basal third with long spatulate androconial scales, inserting in patch on underside forewing; usually only visible from underside. Abdomen dark grey, with pale yellowish anal tufts inserted on well sclerotized plates.
Female. Forewing length 2.0-2.3 mm; wingspan 4.5-4.9 mm. Antenna with 21-26 segments. As male, but patch underside forewing and androconial scales absent; forewing sometimes completely unicolorous; abdomen dark grey, without anal tufts.
Male genitalia. Vinculum anteriorly slightly bilobed. Uncus with widely separated conical and curved horns. Gnathos with long slender, widely separated posterior processes. Valva with pointed distal process, slightly less than valva length; inner margin forming a distinct inner lobe, which does not reach to tip of distal process; sublateral processes short, less than 1/4 transtilla length. Aedeagus long and anteriorly widened; vesica with single coil anteriorly, several very long and strongly curved cornuti following the coil, with several associated small cornuti, more posteriorly with rows of shorter spines at both sides, distally also a row at right hand side of aedeagus; manica absent.
Female genitalia. Accessory sac with many longer spines posteriorly, all directed anteriorly, inserted on two cushion-shaped bulbous lobes; ductus spermathecae with 5 convolutions, at least 2 as long as bursa.

Associations: 

Hostplant. Quercus trojana; since the record in Turkey is outside the range of Q. trojana, it probably also feeds on another oak.
Leafmine. A gallery, according to the original description not different from S. zangherii or S. szoecsiella, which feed on the same host, egg position not noted. Larva yellow.

Distribution: 

Northern Greece and Turkey (new record). From sea level up to 2400 m in Turkey.

Life cycle: 

Life-history. Probably bivoltine, larvae found in June, adults emerging almost immediately in June; also found in July and October.

Citation: 

This taxonomic description is based on Van Nieukerken (2003).

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