Stigmella gallicola van Nieukerken, Nishidaan Nieukerken et al., 2016
- GBIF Backbone Taxonomy
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- Nieukerken EJ van, Doorenweerd C, Nishida K, Snyers C. New taxa, including three new genera show uniqueness of Neotropical Nepticulidae (Lepidoptera). ZooKeys 628: 1-63. doi: 10.3897/zookeys.628.9805. (2016).
- Stigmella gallicola
Male (Fig. 112) (See Remarks). Forewing length about 2.3 – 2.5 mm; wingspan about 5.2 – 6.0 mm. Head: palpi fuscous, distally silvery shiny; face black, silvery shiny, with blue iridescence; frontal tuft ferruginous to orange; collar wide, black to dark brown, silvery glossy, with some blue iridescence; scape golden cream to cream, distally darkened with black to grey scales; antenna slightly shorter than half the length of forewing; flagellum with 32 – 34 segments, brown to almost black on upper side and underside. Thorax, tegula and forewing unicolorous, black to fuscous brown, golden glossy, with some purple and blue iridescence; fringe and underside of forewing black, no androconia. Hindwing black on upper side and underside, without spots or androconia; fringe black. Legs blackgrey, glossy; forelegs silvery shiny with blue iridescence. Abdomen entirely black, without anal tufts. Female. Similar to male (see van Nieukerken et al. 2016). Male genitalia (Figs 113 – 115). Capsule longer (about 320 µm) than wide (about 215 µm). Uncus wide but short, not divided into lobes. Gnathos U-shaped. Valva 170 – 200 µm long, 50 – 70 µm wide, with one very small and very slender apical process, and with one inner (dorsal) process; transtilla with short and slender sublateral processes. Juxta with V-shaped thickening. Vinculum with small triangular lateral lobes and short ventral plate. Phallus (Fig. 115) 290 – 375 µm long, 65 – 121 µm wide; vesica with two large horn-like cornuti and numerous minute cornuti. Female genitalia (described in van Nieukerken et al. 2016). Bionomics (described in van Nieukerken et al. 2016). Larvae yellowish green, make galls on Hampea appendiculata (Donn. Sm.) Standl. (Malvaceae) in March, May and June (van Nieukerken et al. 2016). Adults fly in January, March – June, and October.
Diagnosis. The combination of a black or very dark brown scaling of the adult, U-shaped gnathos, gradually narrowed valva with a small slender apical process, and an unusual set of two very large cornuti in the phallus distinguishes S. gallicola Nieukerken & Nishida from all other Stigmella.
Remarks. This remarkable species was originally included in our manuscript as a new taxon (manuscript prepared 2015) on the basis of a single male specimen and, therefore, deposited in the USNM collection as holotype of S. " eunigra ". However, prior to publication of this paper, the species was described by van Nieukerken et al. 2016, and thus in the current paper we provide additional photographs and drawings, and additional information on the male morphology and adult activity.
Distribution (Figs 1). This species known from Costa Rica (Heredia Province and, after van Nieukerken et al. 2016, also in Puntarenas).
Material examined. 1 ♂, COSTA RICA: Heredia, La Selva Field Station (near Puerto Viejo) 21 – 28. iii. 1988, W. E. Steiner, J. M. Hill, J. M. Swearingen, & J. M. Mitchell, genitalia slide no. RA 617 ♂ (USNM).
Biology. Host plant (Figs 19 - 20). Malvaceae: Hampea appendiculata (Donn. Sm.) Standl. A tree, occurring between Honduras and Panama from sea level to 1800 m on both the Caribbean and Pacific slopes in Costa Rica (Fryxell 2007). Figures 17 - 22. Stigmella gallicola, habitat and host plant. 17 General habitat at Alto Masis / Tierras Morenas, a premountain rainforest in Parque Nacional Volcan Tenorio, 13 June 2007 18 same place, 1 June 2007 19, 20 Habitat and host, Hampea appendiculata at same place, 955 m, 14 June 2007 21, 22 Mature galls on primary leaf veins, respectively adaxial and abaxial view, Estacion Biologica Monteverde 1530 m, 22 April 2016, arrows pointing at nectar glands. Gall (Figs 21 - 30). Galls were induced on leaf veins of young leaves and on axillary leaf buds. Galls on leaf veins are ovoid when mature and more swollen on the leaf underside; length 7 - 18 mm diameter 3 - 8 mm (n = 18). Galls on axillary leaf buds ovoid by swelling of entire buds (Fig. 25) length 8.7 - 11.2 mm, diameter 4.1 - 5.5 mm, gall base of ca. 1.6 mm diameter (n = 5). Galls can cause deformation of young leaves. Gall chamber narrow, located longitudinally in central part of gall, and line with compacted dark brown frass on lower part of chamber, part of the frass reaching towards nectary gland (Figs 26, 27). Galls were found on ca. 2 meter-tall treelets or large trees of 8 - 25 m (n = 7), however we were unable to examine higher parts of large trees. Most of the collected galls were empty, having a more or less rectangular-shaped exit slit of less than 1 mm wide (Fig. 30). We found inquiline phorid fly larvae (Diptera: Phoridae) inhabiting old gall chambers. The gall was already recorded by Hanson et al. (2014). Figures 23 - 29. Stigmella gallicola, galls and larvae in Hampea appendiculata, details, all at Estacion Biologica Monteverde, 1530 m. 23, 24 Galls on primary leaf veins of young leaf, respectively adaxial and abaxial view, 8 June 2016 25 Old gall found at axillary leaf bud, same date 26 Longitudinal cut of mature gall with late instar larva in situ, 20 October 2001 27 Transversely cut leaf (young gall in middle) showing gall chamber and frass mass line, 24 October 2001 28 Late instar larva in situ, note packed frass in gall chamber, same date 29 Late instar larva, dorsal view, slightly ex situ after gall dissection, 4 April 2015. Figures 30 - 33. Stigmella gallicola, life history details on Hampea appendiculata, all at Estacion Biologica Monteverde 1530 m. 30 Larval exit hole, 20 October 2001 31 Cocoon spun on host plant under rearing conditions, same date 32 Recently exited mature larva, 29 April 2016 33 Reared holotype male resting on host leaf, 26 October 2001. Egg. Egg position unknown. Probably laid near or at foliar nectaries (nectar glands) abaxially on primary veins of leaf buds or very young leaves. Larva (Figs 28, 29, 32). Early to late instar translucent (n = 7), mature last instar translucent yellowish green, 6.0 mm long (n = 1). Cocoon (Fig. 31). Pale brown to brown, oval, exit slit side is broad and opposite side tapered (apple seed-shaped), 2.8 - 3.2 mm long, 1.7 - 1.9 mm wide (n = 2). Under rearing conditions inside plastic bags, cocoons were constructed on either host leaf surface or on paper towels (n = 5). Under natural conditions in the field, no cocoons were found on host plant leaves or stems near the galls. Voltinism and habits. Larvae were found inside the galls in March, May and June. Adult emergence has been recorded in January, April, May, June and October. Parasitoids. Braconidae: Adelinae: Adelius sp., endo-parasitoid, koinobiont of host larva and pupating inside host cocoon. It was reared from the Alto Masis Station site (n = 2). Adelinae are specialised parasitoids of Nepticulidae (Yu et al. 2011).
Etymology. The specific name is a noun in apposition, derived from the Latin noun galla (= gall) and suffix - cola, " dweller in ".
Other material examined. 6 ♂, 3 ♀, 5 adults, galls, larvae. Costa Rica: 1 ♂, Heredia Province, Puerto Viejo de Sarapiqui, Trimbina Biological Reserve, 10 ° 24 ' 59.81 " N, 084 ° 7 ' 27.82 " W, 161 m, gall inducer on young leaf veins of Hampea appendiculata, adult emergence 18. i. 2003, Kenji Nishida, Genitalia slide JCK 15024; 2 ♀, Heredia Province, Puerto Viejo de Sarapiqui, OTS La Selva Station, main bridge, 10 ° 25 ' 53.42 " N, 084 ° 0 ' 13.22 " W, 50 m, gall inducer on young leaf veins of Hampea appendiculata, e. l. 2 - 5. v. 2002, Kenji Nishida, Genitalia slide EvN 3739, RMNH. INS. 23739; 1 ♂, Alajuela Province, Parque Nacional Volcan Tenorio, Alto Masis Station, 10 ° 36 ' 39.99 " N, 085 ° 0 ' 1.59 " W, 955 m, gall maker on Hampea appendiculata, young leaf veins, adult emergence 20. vi. 2007, Kenji Nishida; 4 ♂, 1 ♀, Puntarenas Province: Monteverde, Estacion Biologica Monteverde, 10 ° 19 ' 06.9 " N, 084 ° 48 ' 29.3 " W, 1530 m, gall inducer on young leaf veins of Hampea appendiculata, adult emergence 17. iii- 10. iv. 2015, cocoons spun approx. 20. iii. 2015, Kenji Nishida (RMNH, MZUCR).