Stigmella pruinosa Puplesis & Robinson

Stonis, Jonas R., Diškus, Arūnas, Remeikis, Andrius, Noreika, Remigijus & Schuster, Jack, 2013, Four new leaf-mining Acalyptris species from Guatemala and Belize, with new data on bionomics of Stigmella pruinosa (Lepidoptera: Nepticulidae), Zootaxa 3737 (2), pp. 101-117 : 112-115

Stigmella pruinosa Puplesis & Robinson

( Figs 48–58 )

Stigmella pruinosa Puplesis & Robinson 2000: 38 , 39.

Material examined. GUATEMALA: 2♂ (only genitalia from developed pupae, no pinned adults/moths available), 1♀, Petén Region, El Caoba, 17°00'N, 89°40'W, mining larvae on Ulmaceae , elevation ca. 300 m, 14.ii.2012, field card no. 5121, LT-GT Scientific Expedition, genitalia slides nos RA477, RA493, RA494) (ZMUC). BELIZE: 2♂ (holotype and paratype), Cayo District, Chiquibul Forest Reserve, Las Cuevas, secondary forest close to Las Cuevas Research Station, 3–16.iv.1998 (R. Puplesis & S. Hill), genitalia slide no. 29124 (BMNH); 9♂, 7♀, San Ignacio, disturbed secondary lowland moist tropical forest at town edge, 17–18.iv.1989 (R. Puplesis & S. Hill), genitalia slide no. 29126♀ (BMNH); 1♂, Pook's Hill Nature Reserve (S of Teakettle Village), secondary lowland moist tropical forest close to main camp, 28–29.iv.1998 (R. Puplesis & S. Hill), genitalia slide no. AD0308 (LUES with future re-deposition at BMNH).

Diagnosis. A very distinctive small, brown-winged Stigmella species characterized by the whitish androconial scales on the upper side of the male forewing, and by the androconial patch on the hindwing (comprising black and whitish scales). According Puplesis & Robinson (2000) some general features of the male genitalia (especially gnathos, transtilla and aedeagus) suggest that S. pruinosa might be related to the oxyacanthella group (= S. crataegifoliella- group, sensu Wilkinson & Scoble, 1979) which is very widely distributed in the Holarctic Region.

Male. Forewing length: 1.5–1.7 mm. Wingspan: 3.3–3.7 mm. Head: palpi cream to grey; frontal tuft usually pale yellow to yellow-orange, occasionally pale orange-ochre; collar whitish or pale cream; eye-caps cream to yellow-cream or grey-cream; antenna brown to dark brown (occasionally pale brown) but brownish cream or whitish on basal part of flagellum and underside, ca. 19–27 segments. Thorax and tegulae brown, sometimes dark brown. Forewing relatively narrow, brown to dark brown with weak gold (not in all examples), occasionally bronze lustre; sometimes with very weak purplish lustre. Forewing with very numerous long and slender grey-white androconial scales on upperside, densely covering entire median area of wing and extending across the width; size of androconial patch may vary considerably from one-third to one-half length of forewing, but base and apex of wing always lack androconia. Cilia brown, usually paler at tips. Underside of forewing brownish, without androconial scales. Hindwing brownish (or grey) with very distinct androconial patch on basal one-third to twofifths; oval androconial patch comprised mainly of deep black scales, but with numerous elongate whitish androconia scattered along middle of patch. Black and whitish androconial scales overlap cilia for one-fifth of their length. Cilia brown. Underside of hindwing brown, without androconia. Legs cream with brown to dark grey lateral shading. Abdomen brown to dark brown on upper side, brownish cream on underside; anal tufts indistinct, cream; scaling of anal plates (i.e. genital segments, mainly valvae) brownish cream.

Female ( Fig. 54 ). Antenna ca. 18 segments. Forewing entirely brown, without greyish white androconial scales; generally paler than in males, but with some overlap – a few females are darker than the palest males (Puplesis & Robinson 2000). Hindwing without androconial patch, entirely brown. Otherwise similar to male.

Male genitalia ( Figs 55–57 ). Capsule 195–230 µm long. Uncus with two strongly sclerotized, quadrate lateral lobes and U-shaped caudal emargination between the lobes. Tegumen band-shaped, slightly extended caudally. Gnathos with two posterior and two anterior processes on well-developed relatively broad transverse bar (central plate); anterior processes one-third longer than posterior ones and twice as widely spaced; lateral arms short. Valva ca. 90–122 µm long, gradually narrowed posteriorly, with small pointed, inturned apical process. Transtilla with well developed transverse bar, rounded laterally, without sublatera1 processes. Vinculum relatively large, with broad emargination anteriorly and with triangular lateral lobes. Aedeagus ( Fig. 56 ) very large, 210–260 µm long (i.e. longer or considerable longer than genital capsu1e), 60–80 µm broad, without apical carinae. Vesica with numerous tiny spine-like cornuti and long row of considerably larger cornuti in apical third; the latter sometime weakly sclerotized and inconspicuous.

Female genitalia ( Fig. 58 ). Tota1 length 570–717 µm. Abdominal tip not considerably narrowed. Apophyses posteriores and apophyses anteriores almost same length (up to 160 µm), but apophyses anteriores more slender. Vestibulum narrow. Caudal part of corpus bursae broad, slightly wrinkled or not wrinkled; remaining larger part of corpus bursae elongate, without pectinations or signae. Accessory sac small, rounded, weakly separated from bursa; ductus spermathecae with about 2.5–3 coils ( Fig. 58 ).

Bionomics. Mines in leaves of Guazuma ulmifolia Lam. (Malvaceae) trees ( Figs 50–52 ). Egg on upper side of the leaf. Larvae mine in January and February. Sinuous gallery of mine filled with blackish frass ( Fig. 52 ). Larva deep green, with brownish green intestine. Larval exit slit on upper side of the leaf. Cocoon beige-cream; length 1.4, maximal width 0.7 mm ( Fig. 53 ). Adults emerged in March; adults also collected at light in April.

Distribution ( Fig. 48 ). The species is possibly widespread and common in Belize: the Maya Mountains, Chiquibul Forest Reserve (premontane moist tropical forest), San Ignacio (disturbed secondary lowland moist tropical forest), and Pook's Hill Nature Reserve (secondary lowland moist tropical forest). In Guatemala, newly recorded from the Petén Region (lowland secondary evergreen broadleaf tropical forest, fig. 49). Because numerous old empty mines found by us in 2012 along villages and roads near Lago Petén Itzá, we presume that this species is common in Petén Region.

Remark. In this paper we provided the first photographic documentation of the genitalia and adult of Stigmella pruinosa , also a description based on specimens collected both in Belize and Guatemala, with the first record of host-plant and documentation of leaf-mines.

Figures

FIGURES 48 – 54. Stigmella pruinosa Puplesis & Robinson. 48, currently known distribution; 49, habitat, lowland secondary evergreen broadleaf tropical forest near El Remate, Petén Region; 50, 51, host-plant (G uazuma ulmifolia Lam., Malvaceae); 52, leaf-mine; 53, cocoon. Scale 1 mm. 54, female adult, Petén Dept., Guatemala. Scale 1 mm.

FIGURES 55 – 58. Stigmella pruinosa Puplesis & Robinson. 55, male genitalia, capsule, genitalia slide no. RA 494. Scale 100 µm; 56, same, aedeagus. Scale 100 µm; 57, general view with aedeagus inside capsule, genitalia slide no. RA 493. Scale 100 µm; 58, female genitalia, genitalia slide no. RA 477. Scale 250 µm.