Stigmella karsholti

Diagnostic description: 

Diagnosis. A large species; male externally superficially resembling S. samiatella or occasionally some other species, but androconials very characteristic. Female resembling other pale headed species, but more coarsely scaled, larger and with more antennal segments than other deciduous oak feeders. Male genitalia characterized by very long aedeagus, only comparable to that of S. basiguttella, but even longer, and terminal large spines absent. Female genitalia very characteristic.


Description. Male. Forewing length 2.8-3.3 mm, wingspan 6.5-6.8 mm. Head: frontal tuft ochreous, on vertex darker grey-brown; collar almost white. Scape white. Antenna pale grey brown, 2/3 of forewing length, with 37-44 segments. Thorax dark bronze brown. Forewing dark bronze brown, more coarsely scaled and darker towards the tip, some of the scales with strong purplish or bluish iridescence; terminal cilia concolorous; underside bronze-brown, slightly darker along costa; from 1/3 to 2/3 of dorsum a brush of long dark fuscous hair-scales. Hindwing coarsely scaled, grey-brown, dorsum with dark grey-brown androconial scales, extending into fringe to at most half cilia length; in addition dark hair-scales of approximately same length as cilia; along costa two types of spatulate androconial scales: very short ones, shorter than hindwing width and longer ones, approximately as long as dorsal cilia; underside grey brown. Abdomen dark grey brown, with pale yellowish anal tufts inserted on well sclerotized plates.
Female. Forewing length 2.5-2.9 mm, wingspan 5.7-6.6 mm. Antenna about half forewing length, with 30-33 segments. Head yellow, otherwise as male except for androconial scales.
Male genitalia. Vinculum anteriorly slightly bilobed. Uncus with two, almost triangular, widely separate processes. Gnathos with long, widely separated posterior processes. Valva with pointed distal process about 1/3 valva length; inner margin sinuous, distally with pronounced inner lobe; sublateral processes about 1/3 transtilla length. Aedeagus very long (longest in the group), aedeagal tube with strongly sclerotized distal lobe at right side, resembling large cornutus; vesica with many cornuti, in basal half only small cornuti, in distal half longer needle-shaped cornuti, forming a group at left side, distalmost at right side a group of smaller ones; manica covering distal 2/3 of aedeagus, covered with small spines and pectinations.
Female genitalia. Bursa reduced, not visible in preparations. Accessory sac strongly sclerotized in distal half, globular (in slides often collapsing), distal 1/2 to 2/3 covered with spines; opening to ductus bursae in anterior part, ductus curving almost 180°; ductus also covered with spines. Ductus spermathecae coiled, with about 11-12 convolutions.


Hostplant. Quercus canariensis (= Q. mirbeckii).
Leafmine. Unknown, the mines from which the females were reared, have not been preserved (O. Karsholt, pers. comm.).


Only known from northern Tunisia in the extensive oak forests near Ain Draham.

Life cycle: 

Life-history. The larva was taken in March, all adults in May.


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