Stigmella salicis

Diagnostic description: 

Diagnosis.  Very closely related to S. myrtillella and vimineticolaS. myrtillella differs from the variable salicis in having usually darker  forewings with more distinct fascia and white cilia; vimineticola differs  salicis from in having indistinct or absent fascia and more yellowish  cilia.  The male genitalia are exceedingly similar and somewhat variable,  the only reliable differences seem to be the cluster of slender spines in  the aedeagus:  in salicis 4-8 of unequal length and almost straight, number  of cornuti and spines 9-13; in vimineticola 4-8 of unequal  length, the longest distinctly curved, number of cornuti and spines 11-14;  in myrtillella 4-7 equally long, short and straight, number of spines and cornuti 7-10.  The female genitalia of myrtillella differ from those of  salicis by shorter, more curved apophyses and shorter anal tufts; those of  vimineticola by sharply pointed ovipositor, long and strong apophyses and  presence of distinct spines in ductus spermathecae.  Also similar to S.  obliquella, see diagnosis of that species.

Morphology: 

Male. Wingspan: 4.9-6.6 mm.  Head: frontal tuft pale ochreous  to yellow or ferruginous; collar yellowish white to ochreous; scape white  to pale yellow; antenna two thirds length of forewing, grey.  Thorax dark  grey-brown.  Forewing: area proximal to fascia varying from yellowish brown  to dark grey-brown, appearing more or less coarsely scaled; fascia yellowish  white to yellow, oblique and constricted in middle; sometimes reduced into  costal and dorsal spots, indistinct or absent; distal to fascia dark grey-  brown to brownish black, coarsely scaled; terminal cilia white to pale  yellow, strongly contrasting with distal part of forewing; pale grey at  tornus.  Hindwing: pale grey-brown; cilia similar.  Abdomen dark grey with  small grey anal tufts. Female.  Wingspan: 4.8-6.2 mm.  Antenna half length of forewing.  Forewing usually darker with more distinct fascia than that of male.  Abdomen dark grey; ovipositor protruding; anal tufts long, yellowish grey. Male genitalia. Vinculum with shallow to distinct  anterior emargination.  Uncus subtriangular with deep, square medial  emargination; paramedial notches varying from distinct to absent.  Gnathos  with horizontal bar and anterior processes forming a rectangular plate;  horns long, well separated at base, parallel to slightly diverging; lateral  arms narrow.  Valva almost parallel-sided, posteriorly rounded with two  short and pointed, inwardly curved processes.  Transtilla with moderately  long to very short sublateral processes.  Aedeagus slightly to distinctly  shorter than genitalia capsule with 5 to 6 unilaterally sclerotized cornuti  and a cluster of 4 to 8 slender spines of unequal length; spines almost  straight.  Number of cornuti and spines varying from 9 to 13. Female genitalia. Corpus bursae with sparse pectinations  and a distinct band of dentate, scallop-shaped chitin plates.  Ductus  spermathecae without spines.  Apophyses long, posteriores slightly shorter  than anteriores.  Anal tufts approximately half length of apophyses.  Ovipositor protruding, tip blunt.

Associations: 

Host plants:  Salix spp., seems to prefer rough-leaved  sallows; rarely on Myrica gale.  Egg: on underside of a leaf, usually close  to a vein or leaf margin.  Larva:  yellow.  Mine : variable;  in small leaves often contorted with confluent windings forming a false  blotch; in narrow leaves usually following leaf margin or ribs; first half  of mine almost filled with frass; second half with frass deposited as a  broad and irregular central line.  Cocoon: pale brown.  

Distribution: 

Widely distributed and common all over Scandinavia and  Finland, including the northernmost region: - C. Europe, Mediterranean and  the British Isles.  

Life cycle: 

Voltinism: in  S. Scandinavia and C. Europe bivoltine;  mines in July and from mid-September  to mid-October.  In N. Scandinavia univoltine with mines from late August  to early September. 


Citation: 

Description based on Johansson and Nielsen (1990)

Notes on description: 
Notes. A paler form of salicis with indistinct or absent fascia and less contrasting cilia occurs in northernmost Sweden and Finland. Males are sometimes difficult to separate from the northern form of S. zelleriella. Also a form with almost black forewings and white fascia is known from northernmost Norway. Stigmella vimineticola (Frey, 1856) (= Nepticula vimineticola Frey, 1856: 382). Contrary to earlier belief (Nieukerken 1986a: 3), S. vimineticola is sufficiently different from S. salicis to warrant specific status. S. vimineticola has been reported from Denmark, Sweden, Norway, Finland, N. Germany, the Netherlands and The British Isles; most, if not all, of these records are misidentifications. Almost all specimens reared from Salix viminalis and closely related Salix species in northwestern Europe are S. obliquella, the rest, S. salicis. Also Frey's material of vimineticola is mixed with by salicis. S. vimineticola is known with certainty from Switzerland, Austria and N. Italy, but it has most likely a wider distribution. See also diagnosis of S. salicis. A male specimen of S. vimineticola "Zürich, Frey coll." with genitalia slide BM24094 is selected as lectotype. (BMNH). Female genitalia , mine on Salix elaeagnos and closely related Salix species.
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith