Liriomyza mystica Boucher & Nishida

Boucher, Stephanie & Nishida, Kenji, 2014, Description and biology of two new species of Neotropical Liriomyza Mik (Diptera, Agromyzidae), mining leaves of Bocconia (Papaveraceae), ZooKeys 369, pp. 79-97 : 81-85

Liriomyza mystica Boucher & Nishida sp. n. Figs 4,8-27,48,50

Type material.

Holotype ♂: COSTA RICA: Cartago: San Ramón de Tres Ríos, 1600 m, (09°56'18"N, 083°58'38"W), ex. Bocconia frutescens , larva exited 5-9.vii.2010; adult emerged 21-26.vii.2010, Kenji Nishida (LEM).

Paratype: same data as holotype (9 ♂; 8 ♀: LEM); same except larva exited: 25-28.vi.2010, adult emerged: 20-22.vii.2010 (14 ♂; 15 ♀: INBio); same except larva exited 29. vi– 4.vii.2010, adult emerged 15-24.vii.2010 (8 ♂; 7 ♀: NMNH); same except adult emerged 21-25.vii.2010 (4 ♂; 4 ♀: CNC); same except along main road, (09°56'20"N, 083°58'55"W), 1500 m, collected 19.xii.2008, emerged 16-20.i.2009, K. Nishida & T. Johnson (1 ♂; 5 ♀: MZUCR). San José: San Isidro de Coronado, Centro. 1420 m, (09°53'18"N, 084°00'22"W), ex. Bocconia frutescens , adult emerged 17.vi.2010, Kenji Nishida (1 ♀: LEM). Puntarenas: Monteverde. Estación Biológica Monteverde. 1538 m, (10°19'09"N, 084°48'32"W), mating on Bocconia leaf. 18.vii.2010, Kenji Nishida (1 ♂; 1 ♀: MZUCR).

Diagnosis.

This species can be distinguished from other Neotropical species of Liriomyza by its completely yellow head and anepisternum, mesonotum almost completely brown to margin of scutellum, usually 2 + 1 dc, legs completely yellow, calypter brown on apical half with margin and fringe brown, and by the shape of the male genitalia and the shape of the anterior and posterior larval spiracles.

Description.

Frons width 0.25 mm; ratio of frons width to eye width 2.3; orbit 0.23 times width of frons at midpoint; frons slightly projecting above or in front of eye in profile (Fig. 8), forming a distinct ring (cheek) below eye; 2 reclinate ors and 2 inclinate ori (Fig. 9) (lower ori sometimes reduced or missing on one side); orbital setulae reclinate, varying in number from about 4-8; first flagellomere rounded, not enlarged in males, with slight apical pubescence; arista 0.30-0.40 mm, with short but dense pubescence; gena deep, slightly extended at rear (Fig. 8); gena height at midpoint: 0.44 times maximum eye height. Eye oblique, bare. Normally 2+1 dc (except 4 specimens with 2+0 dc and 3 specimens with 3+1 dc); acrostichals in about 4 irregular rows; prescutellar acrostichal bristles absent; 2 notopleural bristles; 1 strong postpronotal bristle with 1 or 2 small setulae; anepisternum with 1 strong bristle on posterior margin at midpoint, sometimes with a few extra setulae; katepisternum with one strong bristle on posterodorsal corner, on yellow ground. Fore and mid-tibia without lateral bristle. Wing length 1.50-1.95 mm in male and 1.85-2.20 mm in females; M1+2 ending at wing tip; costa extending to M1+2; last section of CuA1: 1.5-1.9 times length of penultimate. Cross-vein r-m located at midpoint of cell dm. Stridulatory mechanism apparently absent.

Colour. Head (including frons, orbit, face, antenna, palp) entirely bright yellow. Hind margin of eye black for a small section beyond vte; both vt on yellow ground. Occiput black. Eye sometimes with a slight bluish or greenish reflection (not as pronounced as in Liriomyza prompta , Fig. 29); mesonotum almost completely dark brown except for narrow yellow margin posteriorly (Fig. 10), prescutellar area and intra-alar area sometimes slightly paler brown resulting in a weakly defined banded pattern on thorax, most visible in teneral specimen (Fig. 11); scutellum completely yellow with small brown patches laterally. Basal scutellar bristles on brown ground (but at the limit of yellow). Postpronotum, notopleuron and anepisternum completely yellow (at most with a very small pale brown patch on one or two of the sclerites). Katepisternum mostly brown except for upper margin yellow. Calypter brown on apical half, margin and fringe also brown; halter completely white. Legs completely yellow. Abdominal tergites pale brown.

Male genitalia. Distiphallus in the form of two narrow tubules, slightly diverging apically in ventral view (Fig. 13). Mesophallus widest apical section (Fig. 13a), about 1.5-2 times larger than basal narrower tubular section (Fig. 13b). Mesophallus in lateral view with small indent at midpoint (Fig. 12). Surstylus absent. Epandrium without chitinized margin and without spines. Ejaculatory apodeme (Figs 14, 15) weakly sclerotized, symmetrical or sometimes asymmetrical with blade more expanded on one side.

Early stages. Larval length (at maturity): 3.2-4.0 mm, slightly larger than Liriomyza prompta larva. White to creamy white with an internal orange spot at head (live specimens, Figs 24, 25, 27). Anterior spiracles about 0.13-0.23 mm distance from each other; fan-shaped and each with 5 small openings in a single row (Fig. 18). Posterior spiracles divided into 3 subequal projecting bulbs (Figs 16, 17). Cephalopharyngeal skeleton with wide arms (Fig. 19), Each mandible with 2 large teeth. Puparium pale brown to transparent (Fig. 48).

Host plant.

Bocconia frutescens L. ( Papaveraceae ).

Biology.

The larvae feed on spongy parenchyma and other tissues of primary veins and petioles of large, relatively old, mature leaves. Most of the larvae were in leaves of>30 cm long, with>10 mm petiole width and>10 mm thickness (n=120). The larvae were more frequently found mining in the thicker part of the primary vein including the petiole (i.e. less frequently near the leaf apex). One larva was found mining inside of a 2.2 mm width primary vein near the leaf apex. A few larvae were mining thick secondary veins. The mining appears to occur longitudinally, mostly near the upper leaf surface; the larvae left some brown to reddish brown scars along the leaf blade where the vein and blade join (Figs 20, 21, 23). These scars were more easily seen with a strong transmitted light (Fig. 21). The mines (internal tunnels) can also be distinguished by narrow pale lines (Fig. 22). When infested veins were longitudinally dissected, usually one to a few white Liriomyza prompta larvae were observed mining singly and scattered (n=12 leaves) (Figs 23, 24). Some solitary parasitoid wasp pupae were also found among the spongy parenchyma (Fig. 50). The mature fly larvae exited from either the upper side or underside of the veins (n=12 holes) (Fig. 25), each larva making a small oval-shaped hole of 1.1-1.3 mm wide (n=12) (Fig. 26). The tissue around the old exit holes was brown to reddish brown (n=5). The newly emerged larvae wiggled around in rearing plastic bags/cases for a couple of hours to a few hours before settling (Fig. 27) and starting to form a puparium. The larvae readily pupated on the plastic surfaces. In general, the puparia (Fig. 48) were more translucent (translucent pale brown) than those of Liriomyza prompta (translucent brown to dark brown) and the pupa inside was visible. Duration of the larval stage was not recorded. The larvae that exited from veins pupated between 26 to 29.vi.2010 and the adults emerged between 20 to 22.vii.2010, i.e. the pupal stage lasted approximately 25 days (n=29). A mating pair was observed on the underside of a leaf around 7:00 am (site 13). No oviposition behavior was observed for this species.

Parasitoids.

Two species of Pteromalidae : Pteromalinae : sp. 01 from sites 5, 10, 15, parasitizing late instar larva, pupating inside the leaf vein (Fig. 50); Pteromalinae sp. 02 from sites 5, 10, 13, parasitizing larva and pupating inside the host puparium; one species of Braconidae : Opiinae : Opius sp. from site 10, parasitizing larva and pupating inside the host puparium.

Comments.

Liriomyza mystica is most similar to Liriomyza prompta described below and to the Neotropical species Liriomyza commelinae (Frost) and Liriomyza robustae Spencer, especially in the form of the phallus with paired tubules. But these two latter species differ from Liriomyza mystica in a number of characters, including their host plants (both known from plants in the family Commelinaceae ); mesonotum with a distinctive black and yellow pattern; surstylus with a distinct spine; third antennal segment enlarged in males; shape of both anterior and posterior spiracles and pupation occurring inside the mine ( Silva and Oliveira 1952, Spencer 1984, Valladares 1984). The anterior and posterior spiracles of Liriomyza mystica are most similar to those of Liriomyza caesalpiniae Valladares reared from a Caesalpiniaceae , Caesalpinia gilliesii Benth. ( Valladares 1984: figs 14, 15).

Most adult specimens of Liriomyza mystica were reared from site 5, but it was also found at other sites, up to an elevation of 2765 m (Table 1). Considering that Liriomyza mystica larvae feed inside primary veins and petiole of large, mature leaves, it made it difficult to establish Bocconia arborea as possible host due to the problems in studying large trees with large leaves. In sapling trees of ca. 1 m tall (n=2) at Santo Domingo de Heredia (site 9), no larvae or evidence of feeding was observed.

Etymology.

The species name is derived from the Latin mysticus (secret, mystic), referring to the hidden and inconspicuous leaf mines in primary vein and petiole.