Neosphecia cecidogena Moreira & Gorbunov

Moreira, Gilson R. P., Gorbunov, Oleg G., Fochezato, Julia & Goncalves, Gislene L., 2019, A peculiar new species of gall-inducing, clearwing moth (Lepidoptera, Sesiidae) associated with Cayaponia in the Atlantic Forest, ZooKeys 866, pp. 39-63 : 46-53

Neosphecia cecidogena Moreira & Gorbunov sp. nov. Figs 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9

Description.

Male (holotype) ( Fig. 2 A–D ). Alar expanse 23.1 mm; body length 10.8 mm; forewing 10.5 mm; antenna 5.8 mm.

Head with antenna dark brown to black dorso-externally and yellow ventro-externally; scapus yellow and narrowly lined with dark brown dorsally; frons entirely dark brown with purple-blue sheen; vertex black with dark-blue sheen and an admixture of individual white and yellow hair-like scales; proboscis completely undeveloped; labial palpus dark brown to black with an admixture of yellow scales dorsally and white, long, hair-like scales ventrally in distal half; occipital black with a few white scales dorsally.

Thorax with patagia dark brown to black with a small, yellow, transverse spot anterior-ventrally; tegula dark brown to black with yellow, hair-like scales distally; mesothorax entirely dark brown to black; metathorax dark brown to black with two tufts of yellow, hair-like scales laterally; thorax laterally dark gray-brown with bronze-violet sheen. Legs with neck plate dark brown to black; fore coxa dark brown to black with a narrow, yellow exterior margin; hind tibia dark yellow with an admixture of black elongated scales on basal half; spurs dark yellow with golden sheen and a few black scales exterior-basally; hind tarsus dark yellow with a dense admixture of elongated black scales dorso-externally. Forewing: dorsally dark brown with dark-violet sheen and an admixture of individual yellow-orange scales, more dense distally and at anal margin; transparent areas present but very small: anterior and posterior ones very narrow, external one divided into two very short cells; cilia dark brown to black with dark violet-purple sheen. Hindwing transparent; veins broadly covered with dark brown and a few yellow-orange scales; discal spot undeveloped; outer margin about as broad as cilia, dark yellow and narrowly dark brown distally; cilia dark brown with dark violet sheen.

Abdomen including anal tuft black with dark blue sheen and a few yellow scales at base of second tergite.

Male genitalia ( Fig. 3 A–D ). Tegumen-uncus complex relatively broad; uncus bilobed distally, with a relatively large semi-oval plate of strong, short, pointed setae internally on each side distally; gnathos rather small, membranous, with a small, narrow, slightly sclerotized plate medio-basally; valva broad, subrectangular, with dorsal margin concave mesally and rounded distally; distal field of setae not developed; setae of medial field restricted to a path on ventro-distal margin; ventral lobe relatively broad on 2/3 basal section, narrowed distally; saccus narrow, ca 0.7 valva in length; aedeagus tubiform, narrowed distally, ca 1.3 × valva length; vesica with numerous minute cornuti.

Female (paratype) ( Fig. 2 E–H ). Antenna with more broad yellow stripe ventro-externally; vertex with more numerous white hair-like scales; labial palpus with more numerous yellow scales dorsally; patagia with more yellow scales anteriorly; legs with more numerous yellow scales; both tergites 4 and 5 with a sparse, dark yellow stripe medially. Color patterns otherwise as in male.

Female genitalia ( Fig. 3E ). Papillae anales membranous, covered with short and a few long setae; eighth tergite relatively broad with relatively long setae distally; posterior apophyses about 1.2 × longer than anterior apophyses; ostium bursae opening near posterior margin of sternite seven, slightly funnel-shaped; antrum membranous, narrow and short; ductus bursae narrow, slightly broadened medially, about as long as anterior apophyses; corpus bursae membranous, elongate-ovoid, ca 1.5 × as long as anterior apophyses, without signum.

Individual variability.

The type series practically invariable in individual size and in the coloration of various parts of the body and wings.

Differential diagnosis.

This new species looks like Melittina nigra Le Cerf, 1917 (type locality: “Brésil, ex E. Le Moult, Coll. F. Le Cerf"; Le Cerf 1917: 240), from which it can be easily distinguished by the absence of the proboscis (well developed in M. nigra ) and poorly developed transparent areas of the forewing (large, well developed, external transparent area divided into seven cells between veins R3-CuA2 in M. nigra ; compare Fig. 2 with Le Cerf 1917: pl. 477, fig. 3933). From N. combusta Le Cerf, 1916 (type locality: "Bolivie, Cochabamba, Yunga del Espiritu-Santo; ex P. Germain (1888 –1889)”; Le Cerf 1916: 9) this new species differs by the presence of transparent areas of the forewing (completely opaque in N. combusta ), by the coloration of the abdomen (dorsally tergite 3 with a narrow yellow stripe anteriorly in N. combusta ), and by the coloration of the hind tarsus (dark brown to black in the compared species; compare Fig. 2 with Le Cerf 1916: pl. 375, fig. 3137). Neosphecia cecidogena sp. nov. cannot be confused with any other Melittiini of the Neotropical region by its generic characters.

Etymology.

The species name, an adjective, is derived from a composition between the Portuguese “Cecidia” (a gall) and the suffix gena (derived from the Latin verb “gigno”, be born). Thus, the epithet refers to the cecidogenous habit of the new described clearwing moth.

Material examined.

All specimens were either dissected or reared from galls associated with Cayaponia pilosa (Vell.) Cogn. ( Cucurbitaceae ), from the Centro de Pesquisas e Conservação da Natureza Pró-Mata (CPCN Pró-Mata, 29°28'36"S, 50°10'01"W, São Francisco de Paula Municipality, Rio Grande do Sul State (RS), Brazil; 04-06.IV.2014, G.R.P. Moreira & R. Brito legs., LMCI 263; 21-24.VI.2016, G.R.P. Moreira, R. Brito, J. Fochezato legs, LMCI 306; 28-30.VI.2017, G.R.P. Moreira and J. Fochezato legs., LMCI 319; 01-02.VIII.2017, G.R.P. Moreira and J. Fochezato, LMCI 320; 20-23.III.2018, G.R.P. Moreira, V. Becker, A. Moser, R. Brito & J. Fochezato legs., LMCI 326.

Type material (all pinned-dried adults). Holotype: ♂ LMCI 319-83; Paratypes: 1♂, LMCI 319-84, with genitalia preparation on slide; 1♀, LMCI 263-52, with genitalia preparation on slide; 1♀, LMCI 319-82, donated to MCTP (64103); 1♀, LMCI 319-85.

Non-type material. Adults (pinned-dried): 1♂, with genitalia preparation on slide, LMCI 319-81; 1♀, with genitalia preparation on slide, LMCI 306-19. Immature stages (fixed in Dietrich’s fluid and preserved in 70% ethanol): ca 30 eggs, dissected from female during genitalia preparation, LMCI 263-52b; 2 last instar larvae (LMCI 263-49 and 326-148); 2 pupae (LMCI 263-51 and 309-02); 12 dis sected, mature galls (LMCI 263-35); 5 empty, senescent galls with pupal exuviae (LMCI 319-86). Also, 6 last instar larvae, preserved in 100% ethanol at −20 °C, used for DNA extraction (4 specimens, LMCI 263-33; 2 specimens, 326-146), and 2 last instar larvae preparations, mounted in Canada balsam on a slide (LMCI 263-42, 43).

Description of immature stages.

Eggs ( Fig. 4 ): light brown, obovoid, with the anterior end slightly flattened; maximum length (average ± standard deviation) = 0.05 ± 0.01 mm, maximum width = 0.39 ± 0.01 mm, n = 6. Surface of chorion with faint carenae, delimiting irregular, mostly hexagonal cells and minutely pitted, forming a continuous meshwork-like plastron (sensu Hinton 1981), except for the anterior end where corresponding holes are sparse. Micropylar area on anterior pole, consisting of a subtrapezoidal indentation in the center, which is surrounded by a rosette of about 20 subpentagonal cells that increase in size centrifugally.

Last instar larva ( Figs 5 , 6 , 9D ): head capsule width (average ± standard deviation) = 2.39 ± 0.06 mm; body length = 10.34 ± 2.45 mm, n = 4. Body light yellow; head tan-brown, with a clearer, dorsal, irregularly shaped area, covering the frontoclypeus, adfrontal area and adjacent portions; this area projects latero-posteriorly, ending close to the posterior margin of the head. Prothoracic shield slightly melanized except for a pair of faint patches formed by pigmented spots, located mesally on posterior margin. Anal plate and prothoracic legs not melanized ( Figs 5C, D , 9D ). Setae mostly reduced in size, on pinacula ( Fig. 6G, K ) that are inconspicuous under light microscopy (same color as body) ( Fig. 5 C–E ). Head: wider than long, with lateral margins convex, slightly hypognathus; frontoclypeus subtriangular, higher than wide, extending to three-quarters of epicranial notch; ecdysial line weakly defined, reaching close to epicranial notch and delimiting a narrow adfrontal area ( Fig. 5 A–D ). Six poorly developed, laterally located stemmata ( Fig. 6A, C ). Antennae ( Fig. 6B ) two-segmented; basal segment with four sensilla on distal margin, two short and stout, one minute and one long, ca 10 × the length of the others; distal segment much thinner and shorter, bearing three short sensilla on distal margin. Labrum slightly bilobed, with three pairs of setae laterally on distal margin, and one pair centrally on proximal base. Mandible well developed, with four cusps along distal margin and two small setae mesally on external surface. Maxilla ( Fig. 6D, E ) with palpus and galea well developed. Spinneret short, conical ( Fig. 6D, E ). Labial palpus ( Fig. 6E ) bisegmented; distal segment thinner and shorter, with well-developed apical seta. Thorax (T) and abdomen (A): integument covered with microtrichia, except on pinacula ( Fig. 6G, K, L ). Thoracic legs well developed, with stout tarsal claw ( Fig. 6H, I ). Circular spiracles with slightly elevated peritreme, laterally on T1, A1-8. Abdominal pseudopodia absent, replaced by pairs of ambulatory calli ( Fig. 6L ) on A3-6 and A10, without crochets.

Chaetotaxy ( Fig. 5A, B ). Head with F unisetose; C group bisetose; A group trisetose, forming an obtuse triangle with A3 closest to stemmata; AF group bisetose; P unisetose; Md group absent; L unisetose; S trisetose; SS trisetose (not drawn). A3 and P1 about equal in length, longest setae on head. T1 with D group bisetose; XD bise tose; SD bisetose; L bisetose; SV bisetose. T2-3 with D group bisetose; SD unisetose; L1 unisetose; SV unisetose. A1-7 with D group bisetose; MD unisetose; SD bisetose; L bisetose; SV and V unisetose. A8 with D group bisetose; MD unisetose; SD1 unisetose; L bisetose; V unisetose. A9 with D group unisetose, SD bisetose; L unisetose. A10 with D group bisetose; SD bisetose; V unisetose, and three pairs of unnamed setae on lateral of calli.

Pupa ( Figs 7 , 8 ). Body length (average ± standard deviation) = 11.52 ± 0.67 mm; n = 5. Yellowish brown, becoming dark brown near adult emergence ( Fig. 7C ). Head with stout, short, bow-shaped frontal gall-cutter process in dorsal view ( Figs 7A, C ), which is continued latero-caudally up to eye margin by slightly elevated ridges that limit depressions on frons under lateral view. Vertex with two pairs of small setae laterally. Clypeus little pronounced, with one pair of small setae laterally; labrum short, slightly bilobed ( Fig. 8B ). Antennae clubbed at the end, reaching anterior portion of third abdominal segment. Mandibles small, rounded, meso-anterior to the eyes. Maxillary palpi small, rounded, latero-posteriorly to the eyes. Proboscis shorter than and laterally margined by the prothoracic legs; galea converging mesally along the second half portion. Labial palpi contiguous on the center, extending to half length of the galea. Pronotum fairly developed, bearing a central ridge that extends caudally along the meso- and metanotum. Hindwings concealed by forewings, both extending to sixth abdominal segment. Protho-, meso-, and methatoracic legs reaching the second, fifth, and seventh abdominal segments, respectively. Thoracic and abdominal setae extremely reduced in size: one pair, latero-dorsally, on meso- and metathorax, and A2-A9; another pair, subspiracular, on A2-A7. Abdominal spiracles rounded, with slightly elevated peritreme ( Fig. 8E ), laterally on A2-A7; spiracle on A8 closed. Basal and caudal transverse rows of spines ( Figs 8D, F ) present from abdominal segments two to seven on males; only one row of such spines is found on segment seven of females, and also on segments eight and nine on both sexes. Last abdominal segment with four pairs of stout, scaly spines on caudal margin: two pairs in latero-dorsal and two pairs in latero-ventral position ( Fig. 8H, G ).

Distribution.

This new species is known only from the type locality, the humid forest portions of the CPCN Pró-Mata, São Francisco de Paula municipality, Rio Grande do Sul State, Brazil.

Host plant.

Galls of N. cecidogena have been found only in association with Cayaponia pilosa (Vell.) Cogn. ( Cucurbitaceae ), which is distributed in the ombrophilous Atlantic Forest of southern Brazil (from Minas Gerais to Rio Grande do Sul State) ( Gomes-Klein et al. 2015). Biology and natural history of this cucurbit are poorly known. It is a herbaceous, prehensile vine ( Fig. 9A ), which bears pairs of forked, axillary tendrils, simple, alternate leaves with lamina that may vary from entire, to three to five lobed; flowers are solitary, axillary, and with penduncles varying from 7 to 9 cm long; fruits are ellipsoid and ca 2 cm in length, which are initially green ( Fig. 9B ) but changing to wine-colored when mature ( Porto 1974; Villagra and Romaniuc Neto 2011). At the type locality, C. pilosa plants are found scattered on forest borders, particularly along trails.

Natural history.

The unilocular, cylindrical galls of N. cecidogena measure on average ( ± standard deviation) 3.44 ± 2.51 cm (n = 9) in length when mature. They appear individually and from the beginning develop externally on axillary buds of C. pilosa vines. Contrary to the oval C. pilosa fruits ( Fig. 9B ), N. cecidogena galls are not pedunculate ( Fig. 9C ). They are green during development and later turn dark brown with the progress of senescence ( Fig. 9I ). The internal chamber is filled with a yellowish nutritive tissue ( Fig. 9D, E ) which is consumed by larvae during development. With the end of feeding, the last larval instar builds a blackish, circular operculum ( Fig. 9 F–H ) that splits the chamber into two sections, one distal, where the frass is deposited, and one basal, which has the distal portion of the wall lined with light-gray silk ( Fig. 9E ) and where pupation occurs. Achieving maturation, the wall of the gall hardens with the exception of the distal, pointed end, which remains thin and soft and through which adult emergence occurs ( Fig. 9I ). During emergence, with the action of the frontal process and body contortions, the pupa detaches the operculum and ruptures the distal, weaker portion of the wall. By continuing these movements and anchoring the body laterally with its abdominal spines, the pupa pushes itself partially out of the gall. During this process, the anterior portion of the exuviae is split, allowing adult emergence. In all cases of adult emergence under laboratory conditions, the anterior part of the pupal exuviae (head and thorax) was found protruding to the outside ( Fig. 9J ), while the posterior third remained in the chamber.

A few C. pilosa plants have been found at the type locality bearing from one to five N. cecidogena galls per plant. Field collections carried out during five consecutive years at the type locality indicated that it is a univoltine species, larvae growing during the summer when young galls are seen on C. pilosa vines. Fully developed galls containing last instar larvae have been collected mainly during autumn. When brought to the laboratory, these remained larvae during the winter, apparently in a diapause state. Pupation in this case occurred during the first week of September and emergence a few days later during early spring. The absence of a proboscis suggests that adults of N. cecidogena are not active feeders. The appearance of a substantial number of corionated eggs in the abdomen of dissected females shortly after emergence in the laboratory indicates that reproduction occurs early in adult life, and thus, adults may not live long.

Figures

Figure 2. Pinned-dried Neosphecia cecidogena adults, with corresponding heads in detail A-D male (holotype, LMCI 319 - 83) E-H female (paratype, LMCI 319 - 85); dorsal (A, C, E, G), ventral (B, F) and lateral (D, H) views. Scale bars = 0.5 mm (C, D, G, H); 4 mm (A, B, E, F).

Figure 3. Neosphecia cecidogena genitalia morphology under light microscopy A male (LMCI 319 - 84), general, ventral view (unrolled preparation, sensu Pitkin 1986; aedeagus omitted) B right half of the tegumen-uncus complex, mesal (pointed by closed arrow in A asterisk indicates anal tube) C distal portion of left valva in detail (enlarged area marked with a rectangle in A), ventral D aedeagus, lateral E female (LMCI 306 - 19), general, ventral (open arrow points to missing distal portion of the right anterior apophysis, broken off during preparation). Scale bars = 0.1 mm (B-D); 0.3 mm (A, E).

Figure 4. Egg of Neosphecia cecidogena under scanning electron microscopy A general view B chorion in detail C micropyle area. Scale bars: 100, 15, 20 µm, respectively.

Figure 5. Neosphecia cecidogena last larval instar under light microscopy A cephalic chaetotaxy, frontal view B thoracic and abdominal chaetotaxy, lateral C, D head in detail, anterior and lateral, respectively. E last abdominal segments in detail, dorsal. Scale bars: 200 µm (A, D); 0.4 mm (E); 0.5 mm (C); 1 mm (B).

Figure 6. Morphology of Neosphecia cecidogena last larval instar under scanning electron microscopy A head, antero-dorsal view B antenna, anterior C stemmata, lateral D maxillae and labium, ventral E spineret, lateral F prothoracic shield, dorsal G meso- and metathoracic segments, dorsal H prothoracic leg, posterior I tarsal claw in detail, posterior J prothoracic spiracle, lateral K second to fourth abdominal segments, lateral L abdominal callus in detail, ventral. Scale bars: 20 µm (E, I, J); 40 µm (B), 100 µm (C, D, H, L); 0.5 mm (A, G, K).

Figure 7. Neosphecia cecidogena pupa under light microscopy, in dorsal (A), ventral (B) and lateral (C) views. Scale bar: 1 mm.

Figure 8. Neosphecia cecidogena pupal morphology under scanning electron microscopy A, C head, ventral and lateral views, respectively B clipeal seta in detail D third to sixth abdominal segments, lateral E fourth abdominal spiracle, lateral F spines of fourth abdominal segment in detail, lateral G last abdominal segments, posterior H spine of last abdominal segment, mesal. Scale bars: 40 µm (H); 50 µm (B, E); 100 µm (F); 200 µm (C, G); 0.4 mm (A); 0.5 mm (D), respectively.

Figure 9. Natural history of Neosphecia cecidogena on Cayaponia pilosa A host plant at the type locality B young fruit, lateral C fully developed gall on axillary region, lateral D, E basal portion of median-sized gall sectioned transversally, showing yellowish nutritive tissue (pointed by closed arrows) (D) longitudinally sectioned medium-sized galls, showing larval feeding scars on nutritive tissue (some are indicated by open arrows) F longitudinally sectioned mature gall, with last instar larva (asterisk) inside (closed and open arrows indicate frass and operculum, respectively) G transversally sectioned, senescent gall showing detached operculum (indicated by seta) and internal wall covered by silk H longitudinally sectioned senescent gall showing internal silk covering (proximal limit pointed by closed arrow) I senescent, overwintering gall, lateral (seta indicates direction of adult emergence) J distal portion of senescent gall, showing pupal exuvium left partially protruded after adult emergence (marked with asterisk). Scale bars: 2 mm (G, H); 3 mm (D-F); 4 mm (J); 6 mm (I); 9 mm (C); 1 cm (B); 9 cm (A).