Table 2 Results of the morphological study. The order follows the diagnostic value for species identification. Numbers in parentheses give the count of an observed characteristic per total number of examined characteristics (see Additional file 2 for a detailed evaluation)
Character | Ae. koreicus | Ae. j. japonicus | Diagnostic value for species identification |
|---|---|---|---|
 Hind femur | Base entirely pale-scaled (43/43) | Dark subbasal band (30/30) | Diagnostic character |
 Hind tarsomere IV | Complete pale basal ring (41/41) | Most often dark (17/29), few pale scales (6/29) or incomplete pale ring (6/29) | Very variable in Ae. j. japonicus |
 Subspiracular patch (L + R) | Usually present (81/86), size very variable if present, 1 to 28 scales, mean number and median 10 | Usually absent (59/60), maximum 1 scale counted (1/60) | Ae. koreicus can lack this patch, size varies a lot |
 Pedicel scales | Usually more pale than dark scales (40/43) | Usually more dark than pale scales (28/30) | Not easily quantifiable, sometimes scales are evenly distributed in both species |
 Costa | Usually no pale scales present (36/43), maximum few pale scales present (7/43) | Usually with pale scales (29/30), only once entirely dark | Number of pale scales very variable in Ae. j. japonicus |
 Postpronotum | Often no dark scales present (25/43) or only few dark scales (16/43); clear pattern of dark scales only twice | Usually no dark scales present (29/30), maximum of a few dark scales present (1/30) | Usually no or only a few dark scales present in both species but pale scales more whitish and less crescent shaped scales counted in Ae. koreicus |
 Fork scales | Usually no pale scales present (40/43), maximum 3 pale scales counted | Usually some pale scales up to 16 present (19/30) or no pale scales present (11/30) | Not easily recognizable, mainly dark in both species |
 Hind tarsomere V | Most often dark (29/41), few pale scales (10/41) or incomplete pale ring (2/41) | Entirely dark (29/29) | Usually dark in both species |
 Antepronotum | Broad pale scales (43/43) | Broad pale scales (30/30) | No discrimination possible |
 Color of scutal stripes | All scales golden-yellow, prescutellar area usually with paler scales (37/43), never silver-white | All scales golden-yellow (29/29) | No diagnostic character |
 Length of anterior dorsocentral stripes on scutum | Stripes usually reach the middle of the scutum (40/42) or slightly shorter (2/42) | Stripes reach at least the middle of the scutum (4/29), usually longer (25/29) | No diagnostic character |
Tergite pattern | |||
 Basomedian patch | Usually present on segments II-VII (38/41), at least present on segments II-VI (3/41) | Present on segments II–V up to segments II-VII (20/28), only on segment II (1/28) or absent on all segments (7/28) | No diagnostic character, very variable in Ae. j. japonicus |
 Size of basomedian patch | Ranges from a few pale scales (11/41), over pale spots (14/41) to clearly visible bands (15/41); once the patch was fused with the basolateral patches | If present, usually only a few pale scales (20/21), maximum a pale spot present (1/21) | No diagnostic character |
 Basolateral patch | Present on segments II–VII (43/43) | Present on segments II–VII (30/30) | No discrimination possible |
 Tergit VIII | Basolateral patches usually fused (35/42) | Basolateral patches usually not fused (21/28) | No diagnostic character |