Ectoedemia occultella ( Linnaeus, 1767 )

Yagi, Sadahisa, Hirano, Nagao & Hirowatari, Toshiya, 2019, Taxonomic notes on the Ectoedemia suberis and angulifasciella species groups in Japan (Lepidoptera: Nepticulidae), Zootaxa 4706 (2), pp. 201-230 : 224-225

5. Ectoedemia occultella ( Linnaeus, 1767)

( Figs. 40 , 48–50 , 56 , 62 )

For synonymy see van Nieukerken et al. 2016.

Type locality: Hammerby ( Sweden) .

Material examined. JAPAN. Hokkaido: 3 ♂, 1♀, Hanazono, Kutchan-cho, 6.x.2017, larvae on Betula ermanii , ex. pupa 20.v.2018, S. Yagi, genitalia slide no. SY578, DNA extraction no. SaY150. Honshu: [Nagano Pref.] 1 ♂, Tateshina-kogen, 2.x.1969, larva on Betula platyphylla , 9.v.1970, H. Kuroko ( OPU) .

Male. Forewing length 2.2–2.3 mm, wingspan 5.0– 5.3 mm (n = 4). Female. Forewing length 2.7 mm, wingspan 6.2 mm (n = 1).

Diagnosis. This species and E. minimella (Zetterstedt,1839) can be easily distinguished from others of the angulifasciella group by the absence of a cilia line and a long pseuduncus. Ectoedemia occultella is similar to E. minimella , and it can be distinguished by the frontal tuft in female (male with blackish tuft in E. minimella ) and vesica without elongated cornuti.

In East Asia a morphologically very similar Sorbus -feeding Ectoedemia occurs sympatrically with E. occultella ( Hirano 2013; van Nieukerken et al. 2016: Supplementary material 2). However, E. occultella can be separated from it by the fuscous forewing (fuscous forewing with stronger purple sheen in the Sorbus -feeding Ectoedemia ), sharper pseuduncus (a little shorter and not so sharp in the Sorbus -feeding Ectoedemia ), and slender sublateral process of transtilla in male genitalia (basally thick in the Sorbus -feeding Ectoedemia ). These two species are very difficult to distinguish and their host plants occur sympatrically. Therefore, records that are not based on reared specimens need to be confirmed.

Barcode data. A DNA barcode of one specimen (BOLD: ADX7742) was generated and deposited in the Gen- Bank with accession number LC467971 . The barcode of this species is closest to that of " Ectoedemia StephanandraKorea " based on BLAST in GenBank, and the similarity between them is 95.29%.

Biology. The Japanese population utilizes Betula platyphylla Sukaczev var. japonica (Miq.) H. Hara and B. ermanii Cham. Similar mines also were found on B. maximowicziana Regel and B. corylifolia Regel et Maxim. Eggs are deposited on the underside of the leaf. The leafmine starts as a blotch, filled with blackish frass, and later becomes a larger blotch and the blackish dense frass is glued to the upper surface at the center of the mine, forming a dark spot under which the larva can hide. Larvae are pale greenish cream; found in October, which indicates univoltinism.

Distribution ( Fig. 62 ). Northern Holarctic: from westernmost Europe to Japan and throughout northern North America ( Puplesis 1994).

Remarks. A similar shaped mine and larvae are found on Stephanandra spp. in Korea and Japan ( Doorenweerd et al. 2015; Yagi unpubl.).

Figures

FIGURES 38–41. Adults of the Japanese Ectoedemia angulifasciella group, male 38. E. pilosae collected in Shimotakai-machi, Nagano Pref. 39. E. picturata collected in Ishikari-shi, Hokkaido Pref. 40. E. occultella collected in Kutchan-cho, Hokkaido Pref. 41. E. jacutica collected in Tomakomai-shi, Hokkaido Pref.

FIGURES 48–53. Male genitalia of the Japanese Ectoedemia angulifasciella group. 48, 49. E. occultella, genital capsule with phallus removed (Genitalia slide No. SY578). 50. Ditto, phallus (Genitalia slide No. SY578). 51, 52. E. jacutica, genital capsule with phallus removed (Genitalia slide No. SY189). 53. Ditto, phallus (Genitalia slide No. SY172).

FIGURES 54–57. Leafmines of the Japanese species of the Ectoedemia angulifasciella group. 54. E. pilosae on Agrimonia pilosa. 55. E. picturata on Rosa hirtula. 56. E. occultella on Betula platyphylla. 57. E. jacutica on Aruncus dioicus.

FIGURES 58–63. Japanese distribution maps of Japanese species of the Ectoedmeia suberis and angulifasciella groups. 58. E. chasanella. 59. E. ortiva. 60. E. pilosae. 61. E. picturata. 62. E. occultellla. 63. E. jacutica.