Locharcha Meyrick 1923

Genus Locharcha Meyrick

Type species Locharcha emicans Meyrick by monotypy Locharcha opportuna Moreira and Becker, new species

(Figures 1–8)

Type material

BRAZIL: Centro de Pesquisas e Conservação da Natureza Pró-Mata (CPCN Pró- Mata; 29°29 ʹ 16 ″ S, 50°10 ʹ 60 ″ W; 925 m), São Francisco de Paula Municipality, Rio Grande do Sul State (RS), Brazil. Adults preserved dried and pinned, reared by the senior author from galls induced by Palaeomystella fernandesi Moreira & Becker (Lepidoptera: Momphidae) on Tibouchina sellowiana (Cham.) Cogn. (Melastomataceae): LMCI 174, 26 March 2012, by G.R.P. Moreira, F.A. Luz and P. Pollo; LMCI 210, 7–9 March 2013 by G.R.P. Moreira, F.A. Luz and L.T. Pereira. HOLOTYPE: ♂ (LMCI 210–189), donated to DZUP (29.418).

PARATYPES: 1 ♂ (LMCI 210–45), 2 ♀♀ (LMCI 174–179 and 193), donated to DZUP (29.419, 29.420 and 29.421, respectively); 1 ♂ (LMCI 174–180), 2 ♀♀ (LMCI 174–40 and 210–57), donated to MCNZ (81.904, 81.905 and 81.906, respectively); 1 ♂ (LMCI 174–187), 2 ♀♀ (LMCI 174–41 and 176), donated to MCTP (36.227, 36.228 and 36.229, respectively); 1 ♂ (LMCI 210–64), 2 ♀♀ (LMCI 174–194 and 196), donated to VOB.

Other specimens examined

With the same collection data, deposited in LMCI. Adults, dried and pinned: 6 ♂♂ (LMCI 174–174, 177, 182, 191, 210–62; 174–170, with genitalia in glycerine GRPM 50–24), 5 ♀♀ (LMCI 174–185, 188, 195, 210–46; 174–171, with genitalia in glycerine GRPM 50–25). Adults, fixed in Dietrich’ s fluid, preserved in 70% ethanol: 2 ♂♂ (LMCI 174–206 and 207, with genitalia in glycerine GRPM 50–68 and 69, respectively); 2 ♀♀ (LMCI 174–210 and 211, with genitalia in glycerine GRPM 50–70 and 71, respectively). Slide preparations, mounted in Canada balsam: genitalia, 1 ♂ (GRPM 50–63), 2 ♀♀ (GRPM 50–64 and 65); wings, 2 ♂♂ (GRPM 50–59 and 60), 2 ♀♀ (GRPM 50–61 and 62); 2 last-instar larvae (GRPM 59–66 and 67). Immature stages, fixed in Dietrich’ s fluid and preserved in 70% ethanol: 12 last-instar larvae (LCMI 174–55); 9 pupae (LMCI 174–216); 6 dissected galls (LMCI 174–217 to 222). In tissue collection, nine larvae (LMCI 174–53 and 57) fixed and preserved in 100% ethanol, at −20°C.

Diagnosis

A gelechiid lineage with larvae, pupae and adults having a clear affinity with the Teleiodini (sensu Lee and Brown 2008). It is assigned to the (formerly) monotypic genus Locharcha Meyrick, in having males with very similar wing venation patterns, and a strongly asymmetrical valva associated with a dome-shaped tegumen (Clarke 1969). Locharcha opportuna differs from L. emicans Meyrick in having a different wing colour pattern, uncus subtrapezoidal, tegumen longer than wide, and saccus not developed.

It is close to Coleotechnites Chambers, sharing males with an asymmetrical valve, and females with a single spiny, wedge-shaped signum. Locharcha opportuna differs from the species of Coleotechnites in several characteristics: (1) fore wings with veins R 4 stalked to R 5, and M 2 stalked to M 3; (2) hind wings with vein R5 separate from M1, and M2 separate from M3; (3) males without hair pencil in anal area of hind wings; (4) females with anterior margin of sterigma asymmetrical, projecting anteriorly as a process on the left side.

Description

Adult (Figures 1–4). Male and female similar in size and colour. Small moth, with fore wing length varying from 5.33 to 7.15 mm (n = 8). Head (Figure 1B): Frons and vertex mostly cream-white; labial palpus mostly with cream-white scales tipped with dark grey, terminal segments angled slightly upward; antennae dark grey; proboscis yellowish brown. Vestiture moderately smooth. Eye relatively large, rounded; vertical diameter subequal to interocular distance across frons. Ocellus absent. Antenna filiform, longer than half fore wing; flagellomeres completely encircled by single, dense row of slender scales. Clypeus with ventral margin broadly truncate. Pilifers well developed, triangular. Proboscis ~ length of labial palpus. Maxillary palpus short, smoothly scaled, 4-segmented, bent anteriorly and upward. Labial palpi three-segmented, long, bent anteriorly and upward; ratio of segments from base ~1.0: 3.4: 3.4. Thorax: Tegula and mesonotum mostly cream-white, mottled with sparse yellowish scales; tegula with darkgrey scales anteriorly; prothoracic and mesothoracic legs mostly dark grey; metathoracic legs lighter, mostly covered with cream-white scales tipped with dark grey. Fore wings (Figures 1A, 2A): dorsally covered with dark-grey scales along anterior portion and with cream-white scales on posterior margin, forming two wide, irregularly shaped, longitudinal bands; the cream-white band, mottled with yellowish scales; ventrally covered by darkish-grey scales; fringe yellowish; lanceolate, with 12 veins; L/W index ~ 4.3; retinaculum subcostal, with secondary, adjacent subradial setae in female; discal cell closed, ~ 0.63× length of fore wing; Sc ending circa middle anterior margin; R 5-branched; R 1 ending near two-thirds of wing margin; R 4 and R 5 stalked c.1/2 distance from the cell apex; R 4+5 and M 1 separate; M 3-branched; M 2 and M 3 stalked near cubitus; CuA 2-branched; 1A +2A forked basally, extending more than half length of posterior margin. Hind wings (Figures 1A, 2A): light grey on both sides; fringe mostly light grey and yellowish on anterior and posterior margins, respectively; with 9 veins, with a parallel-sided hair pencil at base of anal area; L/W index ~ 4.4, ~ 0.76 fore wing in length; frenulum a single acanthus in male, with two parallel-sided acanthi in female; discal cell closed, ~ 0.63× length of fore wing; Sc+R 1 ending at circa onethird of anterior margin; Rs ending circa two-thirds of anterior margin; M 3- branched, with M 1, M 2 and M 3 separate; CuA 2-branched, CuA 1 and CuA 2 separate; CuP weakly sclerotized, ending at one-third of posterior margin; 1A +2A well developed, ending near basis of posterior margin. Legs with tibial spur pattern 0–2–4; epiphysis present. Abdomen: Mostly covered by cream-white scales; pregenital segments unmodified.

Male genitalia (Figures 2B, 3A–E). Uncus (Figure 3A) small, subtrapezoidal, subequal in length to gnathos and with distal margin setose; tegumen dome-shaped, basal width/length ratio c.0.45; gnathos (Figure 3B) falcate; costal part of left valva (Figure 3C) with bulbous base and distal part slender, long and curved; in locus (Figure 2B), the distal part directed first to the right, and then upward, contouring the tegumen dorsally; saccular part of valve absent; right valve not detected; siccae (Figure 3D) symmetrical, curved mesally and setose, with the aedeagus anchored mesially; phallic fulcrum cylindrical (Figures 3D, E), middle-sized, with distal margin ventrally pointed; vesica without cornuti; saccus not developed.

Female genitalia (Figures 2C, D, 4A, B). Anal papillae laterally compressed, forming a narrow terminal, setose lobe; apophyses posteriores c.3× length of apophyses anteriores; sterigma with anterior margin asymmetrical; tergum projecting anteriorly on the left side as a pointed process (Figures 2D, E, 4A); sternum deeply and narrowly emarginated medially, bearing the ostium bursae on anterior, rounded portion, located on the left ventral side; ductus bursae membranous, shorter than corpus bursae, with ductus seminalis inserted medially; corpus bursae an elongate sac, wall covered by small, stout spines and bearing anteriorly a single spiny, wedgeshaped, centrally constricted signum (Figure 4B).

Etymology. From the Latin opportunus [= opportunist]; feminine. Immature stages

Last larval instar (Figures 5, 6). Body length varying from 3.9 to 5.72 mm (n = 7). Endophyllous, semiprognathous and tissue-feeder. Head, thorax and abdomen with setae well developed. Head: light brown (Figure 5C), smooth (Figure 6A); frons subequal in height and width, extending to circa one-half epicranial notch (Figure 5A, C); labrum (Figure 6B) shallowly notched, with six pairs of setae of unequal size; six stemmata (Figure 6C) arranged in C-shaped configuration. Chaetotaxy (Figure 5A): A group trisetose; L group unisetose; P group bisetose; C group bisetose; F group unisetose; AF group bisetose; S group trisetose; SS group trisetose. A1, A3, P1, P2, S2 and S3 about equal in length, longest setae on head; C1, C2, F1, A2, AF2, L1 intermediate in length; AF1 shorter. Antenna (Figure 6D) twosegmented; mandibles (Figure 6B) broad, with four teeth and two unequal setae on outer surface; labium (Figure 6E) with two-segmented palpi, each bearing a seta; first segment c.8× longer than second segment; spinneret parallel-sided; maxilla (Figure 6F) prominent.

Thorax and abdomen (Figure 5B–D). Prothoracic shield (Figure 5C) dark brown, divided longitudinally by indistinct, unpigmented area; anterior and posterior half of mesothoracic, metathoracic and abdominal segments white and violet, respectively, giving a banded appearance to the larva (Figure 5D); pinacula small, fuscous; anal plate (Figure 5D) dark brown; anal fork black, with three major pairs of prongs; thoracic legs (Figure 5D) dark brown, with a pair of broad bladelike setae (Figure 6G) ventrolateral to terminal claw. Prolegs (Figure 6I) on A3–A6 and A10 of equal size; crochets in a biordinal, uniserial circle, mesial penellipse. Thorax chaetotaxy: T1 with D group bisetose, both located on the dorsal shield, D1 shorter than D2; XD group bisetose, similar in length and both on the dorsal shield; SD bisetose, laterally on the dorsal shield; L group trisetose, L1 longer than L2; SV group bisetose, posteroventral to L2, SV1 slightly longer than SV2; V group unisetose. T2 and T3 with D and SD groups bisetose; SD2 shorter than SD1; L trisetose, L3 posterior to L1–L2, similar in length to L1; SV unisetose; V unisetose. Abdomen chaetotaxy: D group bisetose; A1–A9 with D2 slightly longer than D1, and A10 with D1 and D2 similar in size; A1–A8 with SD group unisetose, A10 with SD1 and SD2 similar in size; L group trisetose; A1–A8 with SV group bisetose, SV1 slightly shorter than SV2, SV1 absent in A9; V group unisetose.

Pupa (Figures 7, 8). Body elongate-oval in dorsal and ventral views, varying from 5.2 to 6.24 mm (n = 8) in length, widest in mesothoracic region; vertex rounded; frontoclypeal suture weakly defined, concave medially; labrum U-shaped, labial palpi barely exposed; maxillary palpi short, not extending beyond anterior margin of eye; maxillae extending distally between sclerites of midlegs; antennae meeting mesially and reaching apical margin of fore wings; apices of metathoracic legs large, with distal part wider than antenna. Integument weakly melanized, with a few microsetae scattered dorsally on cephalic region (Figure 8A) and abdomen, and on anterior portion of abdominal segments. Abdominal terga mostly covered with stout spinelike microtrichia (Figure 8C). Thoracic and abdominal spiracles rounded, with elevated peritreme (Figure 8B); spiracle A8 partially closed. Sternum A6 with a pair of pseudopodium scars (Figure 8E); the scars on A5 are hidden by the overlying wing. Abdominal segment A7 posteriorly fringed with several aligned groups of short, stout setae (Figure 8B, D). Abdominal segments A8–A10 partially fused, with caudal cremaster bearing a few long, stout, distally coiled setae (Figure 8F, G).

Molecular phylogeny. A total of 621 nucleotide sites were analysed, of which 150 (24%) were variable. In accordance with our phylogenetic hypothesis, Coleotechnites was recovered as monophyletic in both methods of inference (BI and ML), with high support values (Figure 9). Because the topologies were identical, we decided to present only one (BI). Locharcha opportuna was placed as a sister lineage of the Coleotechnites species included in the analyses, with strong BPP and bootstrap support values (0.98 and 88, respectively) (Figure 9). The evolutionary divergence observed between comparisons of pairs of species ranged from 2 to 13% (± 1%) (Table 2). The distance between the new lineage described herein and Coleotechnites was 11% (Figure 9). Similarly, the divergence between L. opportuna and the outgroups (Recurvaria and Exoteleia) was c.12% (± 1%). Finally, the K2P distances within Coleotechnites indicate that this group also shows significant diversity, as evidenced by the range of distances (2–8% ± 1%) (Table 2).

Distribution. Locharcha opportuna is known only from the type locality, the Dense Umbrophilous Forest (= Brazilian Atlantic Rainforest sensu stricto) portions of the CPCN Pró-Mata, São Francisco de Paula, Rio Grande do Sul, Brazil. As already mentioned, it occurs in association with fusiform galls (Figure 10A) induced by a species of Palaeomystela Fletcher (Lepidoptera, Momphidae) on the terminal branches of Tibouchina sellowiana (Cham.) Cogn. (Melastomataceae), which is described elsewhere (Luz et al. 2014).

Life history and seasonal abundance. Dissections in the laboratory demonstrated that field-collected galls having intact walls usually contain a larva of Palaeomystella, which can be differentiated from those of L. opportuna by their cream-white bodies (Figure 10B), among other morphological characteristics. Additional galls of this type left to develop in the laboratory showed that pupation of the cecidogenous larva occurs inside, within a tied-silk cocoon. Prior to pupation in this case, the last larval instar builds an operculum (Figure 10D) through which the adult emerges. However, none of these galls was collected attached to T. sellowiana plants during systematic sampling. Observations of individual galls under field conditions, on host plants belonging to the non-destructive sampling group, demonstrated that in fact they are dehiscent, later in ontogeny falling to the ground (Figure 10C), where the cecidogenous larva completes its development. Searches for them on the ground near T. sellowiana trees resulted in collection of many of these operculated galls.

The dissections also showed that galls having open, rounded orifices in the wall (Figure 10E) usually contained a larva of L. opportuna (Figure 10F). Additional galls of this type left to develop in the laboratory showed that these larvae are residents and live solitarily within these galls, feeding intensively on tissues induced to develop by the Palaeomystella species. They use the wall orifices to discharge their faeces. Dissection also showed that pupation in this case occurs inside the gall, within a tiedsilk cocoon that is generally covered with faecal pellets (Figure 10G). By following each gall throughout ontogeny in the non-destructive samples, we found that, in contrast to the galls containing the Palaeomystella larvae, this modified gall morphotype does not fall to the ground, but remains attached to T. sellowiana trees for months. They progressively dry out, turning black after the L. opportuna emerge, and are then frequently used as shelters by small arthropods such as collembolans and acarines.

Of the total of 512 galls dissected in laboratory, 164 (32.05%) had intact walls, containing larva of the cecidogenous insect; 169 (33.0%) had orifices and thus contained a larva or pupa of L. opportuna: the remaining galls had unidentified immatures of either parasitoid wasps (19.92%), predator thrips (9.96%) or cecidophagous curculionids (5.07%). No gall contained living larvae of both the inducer and L. opportuna living together, but dead bodies and exuviae (head capsules) of the former were found in a few galls that contained living larvae of the latter. The number of galls found with two or more larvae of L. opportuna was negligible.

The variation in the frequency of different instars in relation to gall size and colour revealed that early instars (II and III) of the cecidogenous species were found inside green galls, and the later ones (IV) in galls with a colour spectrum ranging from green to violet (Figure 11A). We presume that galls containing first-instar larvae of the cecidogenous species were not detected in our sampling because of their very small size. Head-capsule exuviae from the first instar were frequently found inside galls with a second instar inside, and these were the smallest galls sampled. In contrast, larvae of the kleptoparasite, from all instars, were found primarily in violet galls (Figure 11B).

Within the continuum from green to violet-coloured galls found in the field (Figure 12A), green galls that were dissected had predominantly cecidogenous larvae inside, and the violet ones contained L. opportuna (Figure 12B). The smallest fieldcollected galls contained no larvae of the latter (Figure 12C). We also found a significant correlation between gall size and colour; taking all the galls into account, the intensity of green decreased and the violet increased with the increase in the size of the galls (Figure 12D).

Galls containing either cecidogenous larvae or the kleptoparasite ranged in number from 57 (April 2012) to three (August 2012) per sampling occasion (mean ± standard deviation = 23.78 ± 4.36 per occasion), which correspond to 7.12 and 1.5 per plant per occasion, respectively (= 4.49 ± 2.00 galls per plant per occasion). Young, small galls containing cecidogenous larvae began to appear during early spring (September) when the T. sellowiana trees began to sprout, and reached a clear peak in density during the following autumn, which coincides with the flowering season (April) (Figure 13). The existence of a second, shorter density peak during October suggests that two generations may occur per year, and this possibility should be further investigated. The variation in abundance of the kleptoparasite followed that of the cecidogenous species, with the corresponding density peaks occurring in succession.