Stigmella dentatae

Diagnostic description: 

Diagnosis. A uniform brown species, male distinguished from omelkoi and aladina by the lack of their conspicuous androconial scales, dentatae has only some androconial scales along hindwing costa and brown hindwings; the yellow abdominal tufts separate it also from aladina, which has grey tufts. Male genitalia characterized by basally broadened aedeagus and coiled vesica. females only separated by genitalia: accessory sac folded, with one bend and covered with many spines.

Morphology: 

Description. Male. Forewing length 2.3-2.8 mm (2.55 ± 0.18, n=6), wingspan 5.3-6.4 mm. Head: frontal tuft yellowish orange; collar and scape cream, flagellum grey brown. Antennae with 32-37 segments (n=4). Thorax and forewings uniform brown, cilia similar, their tips greyish; underside brown, without androconial scales. Hindwing disk with brown scales, cilia grey; underside brown, costal edge with pale brown spatulate androconial scales. Abdomen grey-brown, large yellow anal tufts.
Female. Forewing length 2.5 mm (2.42 ± 0.09, n=4), wingspan 5.1-5.7 mm. Antennae with 24-25 segments (n=3). Hindwing pale grey, fringe normal. Abdominal tip blunt.
Male genitalia. Capsule length 265-300 µm (n=4). Vinculum anteriorly concave. Uncus with widely separated horns. Gnathos with widely separated long posterior processes. Valva length 190-215 µm (n=4), with pointed distal process of less than 1/4 valva length, inner margin with rounded lobe. Aedeagus 370-415 µm long (n=4), 185-220 µm wide at bulbous basis, asymmetrically widened at right side; vesica with one coil basally, basal part with many minute cornuti, distal part with ± 70 large cornuti. Manica spinose, distinct.
Female genitalia. T8 rounded, with two longitudinal bare furrows, a group of 6-8 setae centrally. Bursa present, but flimsy, usually lost during preparation; accessory sac folded, with one bend; covered with many spines of different sizes, partly joined in groups; the spines concentrated on right side. Ductus spermathecae long, a long straight part followed by 4 convolutions.

Associations: 

Hostplant. Quercus mongolica (including var. grosseserrata in Japan), Q. dentata (Primorskiy Kray).
Leafmines. Egg on leaf-underside, in single positively identified mine away from a vein. In the mixed series with S. aladina eggs are found on veins or away from them. Mine a long narrow linear gallery with linear black frass throughout, not different from S. aladina. These mines are also very similar to those of the European S. roborella (Johansson).
Larva. Pale yellow, head pale brown, ganglia invisible. Feeds dorsum upwards.

Life cycle: 

Life history. Bivoltine, larvae found in July and September-November; adults fly in May (indoors rearing March-April) and July-September.

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