Fergusonina lockharti Tonnoir

Taylor, Gary S. & Davies, Kerrie A., 2010, The gall fly, Fergusonina lockharti Tonnoir (Diptera: Fergusoninidae) and description of its associated nematode, Fergusobia brittenae sp. nov. (Tylenchida: Neotylenchidae), Journal of Natural History 44 (15 - 16), pp. 927-957 : 930-940

Fergusonina lockharti Tonnoir

( Figures 1–3 ; Tables 1–7)

Fergusonina lockharti Tonnoir, 1937: 141–142 .

Holotype

Western Australia. One male (slide) Mundaring , July 1933, G.A. Currie, bred from leaf gall of E. rudis (ANIC) .

Material examined

South Australia. Two females, seven males (dried) ex gall on Eucalyptus, Stonyfell, R Shakes coll., May 1965 ( WINC); four females, four males (dried) Stonyfell, S.A., May 1965, R Shakes, ex galls on E. camaldulensis (ANIC) ; one female, one male, larvae (spirit) Mt Bold 26 May 1956, JM Fisher, ex galls on E. camaldulensis (ANIC) ; 10 females, 13 males (dried) ex gall on E. camaldulensis, McLaren Vale , 29 August 1985, RS Bungey ( WINC); one female (dried) ex gall on Eucalyptus, McLaren Vale , 28 September 1985, RS Bungey ( WINC); larvae (spirit), ex galls on Eucalyptus sp. , Goolwa, 26 February 1995, KAD ( WINC); larvae (spirit, three slides), ex galls on Eucalyptus sp. , Goolwa, 3 March 1995, GST and KAD ( WINC); 107 females, 103 males (dried), Goolwa, S. Aust, GST and KAD, (from 6 March to 1 April 1995), reared from caged Fergusonina galls on Eucalyptus sp. ( WINC); six females, six males (dried), same label data, except 3 March to 1 April 1995 ( ANIC); 37 females, 46 males reared from Fergusonina galls on Eucalyptus sp. , GST and KAD, March 1995 ( WINC); six females (spirit) same label data ( WINC); five females (slide), same label data ( WINC); larvae (spirit) ex galls on Eucalyptus sp. , Goolwa, 3 March 1995, GST and KAD ( WINC); three females, eight males (slide) Goolwa, 18–23 March 1995, GST and KAD, reared from galls on E. camaldulensis (WINC) ; one gall (dried), Waite Inst., Adelaide, on E. camaldulensis, KAD , 7 December 1995 ( WINC); six galls (dried), Goolwa, GST and KAD, F. flavicornis galls on E. camaldulensis , galls bagged 1 March 1996, coll. 4 May 1996 ( WINC); 30 females, 27 males (dried), Goolwa, GST and KAD, from F. flavicornis galls on E. camaldulensis , galls bagged 1 March 1996, coll. 29 March 1996 ( WINC); one gall (dried), “Temple Bruer”, KAD, April 1996, on E. camaldulensis (WINC) ; seven females, 10 males (slide), Goolwa, 17 May 1996, GST and KAD, from gall on E. camaldulensis (WINC) ; one female (slide), Goolwa, 3 May 1996, GST and KAD, from gall on E. camaldulensis (WINC) ; three females, eight males (dried), Goolwa, 13 October 1996, GST and KAD, ex terminal leaf bud gall on E. camaldulensis (WINC) ; four galls (dried), Goolwa, 1 March 1997, KAD, galls on E. camaldulensis (WINC) ; 92 females, 99 males (dried), 10 females, 10 males (slide), Goolwa, GST and KAD, ex terminal-leaf bud gall, on E. camaldulensis , em. in laboratory March 1997 ( WINC); three females, 14 males (dried) ex gall on E. camaldulensis , “Piccaninny”, Beachport, KAD, 5 April 1997 ( WINC); seven females, nine males (dried) Beachport, “Piccaninny”, KAD, 5 April 1997, ex F. flavicornis terminal leaf bud gall on E. camaldulensis (WINC) ; six females, six males (dried), Goolwa, 17 May 1997, GST and KAD, from galls on E. camaldulensis (ANIC) ; 18 females, 17 males (dried), 15 females, 10 males (slide), Flinders Ranges, Bunyeroo Gorge, October 1997, S Charwat, from gall on Eucalyptus sp. ( WINC); one female, one male, one gall (dried) Woodside, 14 March 1998, J Bellati, from Fergusonina galls on E. camaldulensis (ANIC) ; one gall (dried), Padthaway, JT Jennings, 13 May 1998, on E. camaldulensis (WINC) ; 1 gall (dried), Walkers Flat, 13.iv.1998, JT Jennings, on E. camaldulensis (WINC) ; one female, one male (dried), Flinders Ra., Bunyeroo Gorge, J. Schwarz, 5 May 1998, ex terminal leaf bud gall on E. camaldulensis (WINC) ; 238 females, 150 males, three galls (dried), 182 females, 206 males, larvae (spirit), 22 females, 18 males (slide), Flinders Ranges, Bunyeroo Gorge, J. Schwarz, 6 June 1998, terminal leaf bud gall on E. camaldulensis (WINC) ; larvae (spirit), Melrose, 31 October 1998, GST, from terminal leaf bud galls on E. camaldulensis (WINC) ; three females, galls (dried), Melrose, 1 November 1998, GST and KAD, ex galls on E. camaldulensis (WINC) ; larvae (spirit), Goolwa, GST and KAD, 27 November 1998, ex Fergusonina sp. galls on E. camaldulensis (WINC) ; 10 galls (dried), Goolwa, GST, 7 February 1999, terminal leaf bud gall on E. camaldulensis (WINC) ; one gall (dried), Adelaide, Urrbrae, Waite Campus, GST, 8 February 1999, terminal leaf bud gall on E. camaldulensis (WINC) ; two galls (dried), Stuart Hwy, Cadney Pk, KAD, 9 March 1999, on E. camaldulensis obtusa (WINC) ; one gall (dried), Stuart Hwy, 50 km south of Marla, 9 March 1999, on E. camaldulensis obtusa (WINC) ; five galls (dried), 50 km south of Marla, KAD, 9 March 1999, terminal leaf bud gall on E. camaldulensis (northern form) ( WINC); larvae (spirit), 50 km south of Marla, KAD, 11 March 1999, from terminal leaf bud galls on E. camaldulensis (northern form) ( WINC); four galls (dried), Goolwa, GST and KAD, F. flavicornis galls on E. camaldulensis , dried galls bagged 15 April 1999, coll. 25 August, pinned 25 October 1999 ( WINC); two galls (dried), Meningie, GST and KAD, 20 April 1999, on E. camaldulensis (WINC) ; one gall (dried), 1 km south of Wistow, Mt Barker- Strathalbyn Rd, GST, 25 August 1999, terminal leaf bud gall on E. camaldulensis (WINC) ; one gall (dried), 6 km north of Strathalbyn, Mt Barker-Strathalbyn Rd, GST, 25 August 1999, on E. camaldulensis (WINC) ; two females, two males, one gall (dried), Adelaide, Kensington Park, KAD, 12 November 1999, from terminal leaf bud gall on E. camaldulensis (WINC) ; three galls (dried), Adelaide, Urrbrae, Waite Campus, GST, 11 February 2000, terminal leaf bud gall on Eucalyptus interstans L Johnson and K Hill (WINC) ; two galls (dried), Adelaide, Urrbrae, Waite Campus, GST, 11 February 2000, terminal leaf bud gall on Eucalyptus lockyeri Blaxell and K Hill (WINC) ; larvae (spirit, 11 slides), Ambleside (35°00.28′ S, 138°48.38′ E, elev. 321 m.), 2 km north-east Verdun, GST, 14 February 2000, from terminal leaf bud galls on E. camaldulensis (WINC) ; three galls (dried), 2 km north-west Tailem Bend 35°14.37′ S, 139°26.45′ E, GST, 3 August 2000, on E. camaldulensis (WINC) .

New South Wales. One gall (dried), Hay, KAD, 16 January 1999, terminal leaf bud gall on E. camaldulensis (WINC) ; one gall (dried), Narrandera, Lake Talbot, GST, 23 June 1999, terminal leaf bud gall on E. camaldulensis (WINC) ; two galls (dried), Wilcannia, KAD, 30 May 2005, on E. camaldulensis (WINC) .

Western Australia. Larvae (spirit), Kununurra , KAD, 15 July 1999 , ex terminal leaf bud gall on E. camaldulensis (WINC) ; 50 females, 50 males (dried), Kellerberrin , KAD, 21 October 2000 ( WINC) .

Description

Adult. Measurements as in Tables 1–5. Head, legs and abdomen yellow; second and third antennal segments yellow; arista yellow basally, dark brown to black apically; eyes red-brown with green iridescence in fresh specimens; ocellar triangle brown; presutural mesonotum with 2 + 2 light brown vittae, medial vittae dark brown to black anteriorly; postsutural mesonotum with 3 + 3 dark vittae, median short, submedial long, broad, lateral narrow, often somewhat indistinct; scutellum pale yellowbrown; subscutellum dark brown to black; dorsum of abdomen with striped appearance: first visible abdominal segment predominantly yellow, with lateral margins dark brown, segment 2 yellow with incomplete anterior dark band (broken medially), segments 3, 4 each with complete, brown anterior band and yellow posterior band, dark anterior band of segment 5 expanded medially; in male epandrium yellowbrown, in female segment 6 yellow-brown anteriorly, paler posteriorly; segment 7 strongly sclerotized, dark brown to black.

Chaetotaxy (unless otherwise stated setae black): one pair of ocellar setae and one pair of longer, slightly divergent postocellar setae; a pair of minute setae present within ocellar triangle; inner vertical setae about same length as postocellar setae, outer vertical setae long, divergent; two pairs of orbital setae, the upper pair reclinate, a little longer than postocellar and inner orbital setae; lower orbital setae proclinate, about twice length of interfrontal setae; interfrontal and parafacial setae and setae on cheek (= genae) short, numerous ( Figure 3A ); lower interfrontal setae and inner parafacials yellow; postocular setae about same length as interfrontals; vibrissae long; second antennal segment with one stout seta and three to five short setae; third antennal segment rounded, arista long, micropubescent.

Mesonotum with many short setae; acrostichals not clearly differentiated, except for posterior achrostichals, which are about twice length of anterior ones; posterior three dorsocentral setae long with posterior seta longest; intra-alars not clearly differentiated except for posterior intra-alar which is about same length as penultimate dorsocentral setae; posterior supra-alar setae long, not much shorter than posterior dorsocentrals; anterior supra-alar, anterior and posterior notopleural setae, presutural seta and humeral seta about equal in length; humeral callus with one long seta and one or two short anterior setae; mesopleuron with one long and 9–13 short setae; sternopleuron with one long and two to four short setae; scutellum with very long marginal subapical setae, and shorter marginal basal setae.

Wing ( Figure 1A ) elongate oval; costa terminating beyond R2 + 3, bearing setae and with a humeral break; vein R1 bearing mid-way two sensory pits (not shown); veins R2 + 3 and R3 + 4 parallel, or nearly so, in holotype slightly convergent; anterior cross vein, r-m, shorter, 0.6–0.9 times length of posterior cross vein, r-cu, and shorter or about equal, 0.7–1.1 times distance between them; posterior cross vein complete, two sensory pits on vein R3 + 4 beyond junction of r-m, and two on anterior cross vein, r-m, one of these close to, or on junction of R3 + 4 and r-m.

Male terminalia ( Figures 1B–D , 3B ): epandrium ( Figure 1B ) with numerous small setae, around 15–19 pairs long setae and one pair very long dorsal setae; gonocoxites fused to epandrium, simple; surstylus (= coxites, Tonnoir 1937; telomeres, Harris 1982) simple, distally rounded without apical tooth but with about six to eight small setae on inner surface, separated from epandrium by a shallow cleft; aedeagal apodeme with anterior end rounded in median plane and articulating posteriorly with base of intromittent organ ( Figure 1C,D ); postgonites (= paraphalli, Tonnoir 1937) with one large distal tooth and three lateral teeth.

Female terminalia ( Figures 1E–G , 3C ) comprising abdominal segments 6–9; segment 6 sclerotized cylindrical, its tergite and sternite fused, without lateral suture, with four dorsal and four ventral submarginal setae, the median ones somewhat shorter than the laterals; segment 7 more strongly sclerotized, black with two rows of two dorsal and two rows of two ventral setae, the anterior pair on dorsum shorter than submarginal pair, on ventrum submarginal pair shorter than the anterior pair; segment 8 membranous, invaginated completely within preceding segments but in some preserved specimens protruding, assuming a more elongate structure; segment 9 elongate, acicular, retracting deeply into segments 6 and 7.

Egg. Spindle-shaped, length 0.65 mm, width 0.26 mm tapering to a short blunt “pedicel” at the micropylar (anterior) end and with a long pointed process at the posterior end ( Taylor et al. 1996).

Larva. Three larval instars. Measurements as in Table 6. First instar larva ( Figure 2A ) elongate C-shaped, transparent, 0.54 ± 0.08 (mean ± SD), range 0.44–0.68 mm long, 0.19 ± 0.05, range 0.11–0.28 mm wide (n = 16) with raised annulations delineating body segments, cephalopharyngeal skeleton minute, 0.029 ± 0.002, range 0.026 –0.032 mm long (n = 16), anterior and posterior spiracles not seen, dorsal shield absent. Second instar larva ( Figure 2B ) elongate-ovate, slightly curved from lateral aspect, transparent, 0.78 ± 0.18, range 0.39–1.06 mm long, 0.39 ± 0.10, range 0.21–0.59 mm wide (n = 25), cephalopharyngeal skeleton more prominent, 0.078 ± 0.007, range 0.068 –0.098 mm long (n = 25), anterior and posterior spiracles black, prominent; dorsal shield absent, its position indicated by raised epidermal swelling in vicinity of middorsum in late second instar. Third (final) instar larva ( Figure 2C,D ) ovate-pyriform, 1.69 ± 0.51, range 0.90–2.45 mm long, 0.89 ± 0.30, range 0.48–1.45 mm wide (n = 25), (specimens in ethanol), slightly curved from lateral aspect; head (cephalic segment) retracted within first thoracic segment, bearing anteriorly inconspicuous, dark maxillary sensory papillae proximal to apex of cephalopharyngeal skeleton (antennae not seen); cephalopharyngeal skeleton strongly sclerotized, 0.188 ± 0.020, range 0.158 – 0.211 mm long (n = 25); abdomen with nine segments; a pair of black spiracles prominent laterally on posterior margin of prothorax (anterior spiracles), and laterally on anterior margin of abdominal segment 8 (posterior spiracles); dorsal shield comprising a medial black sclerotized plate 0.30–0.35 mm wide, formed by fusion of posterior portion of third thoracic segment (metanotum), abdominal segment 1 and anterior portion of abdominal segment 2, usually with four, sometimes three and rarely five, anteriorly projecting, stout, sclerotized teeth ( Figure 3D,E ); raised sclerotized spicules on anterior dorsal margin of first thoracic segment, and dorsally on thoracic segments 1 and 2; a transverse series of raised ridges comprising raised sclerotized spicules occurs most prominently on abdominal segments 1–4, becoming less prominent on segments 5–7.

Puparium. Measurements as in Table 7. Barrel-shaped ( Figure 2E ), brown, bearing dorsal shield (see description of larvae); sexually dimorphic in size, with male puparia 2.13 ± 0.14, range 1.90–2.24 mm long, 1.25 ± 0.08, range 1.14–1.34 mm wide, and female puparia 2.50 ± 0.07, range 2.41–2.59 mm long, 1.45 ± 0.05, range 1.41–1.52 mm wide (n = 5).

Gall. Ovoid, bulbous structure ( Figure 3F ), length 18–50 mm, width 12–20 mm ( Taylor et al. 1996) containing up to 200 discrete cavities each containing a single fly larva or puparium. Galls are formed from terminal, meristematic leaf primordia comprising a number of leaves, with the ventral surface of the outermost leaves forming the outer surface of the gall. Leaf veins could be seen on the surface of the gall, and in some, ungalled leaf tissue emerged along the side of the gall or extended beyond the gall tip. Fresh galls mostly green but may become reddish on exposure. At gall maturity, plant stem senesces at the base of gall, which turns light brown and may split with dehydration, and becomes dark brown with age. Old galls may persist on host for several seasons. The histology of these galls was examined (as Fergusobia / Fergusonina -induced shoot bud galls on E. camaldulensis , in Giblin-Davis et al. 2004), where hypertrophied tissue two to nine cells thick was found lining the lumen of the locules.

Comments

Revised diagnosis. For other species of Fergusonina , all life stages have been described only for F. nicholsoni Tonnoir ( Currie 1937) , F. turneri Taylor (Taylor 2004) and F. giblindavisi Taylor ( Taylor and Davies 2008) . Using available descriptions in Malloch (1925, 1932), Tonnoir (1937), Currie (1937), Taylor (2004), Taylor et al. (2007) and Taylor and Davies (2008), F. lockharti can be separated from most species of Fergusonina on the structure of the dorsal shield of the larvae, setation of the female terminalia, structure of the male terminalia and gall type. Of the remaining species where descriptive data could not separate F. lockharti , type material has been examined. From these species, it differs as follows: F. lockharti is similar to F. flavicornis in general colour pattern and setation of the female terminalia and is separated only by the degree of pigmentation of the ‘pleurae’ in the key of Tonnoir (1937). Fergusonina lockharti differs from F. flavicornis in being considerably larger and the yellow band on the posterior margin of each abdominal tergite is wider (the abdomen of the holotype of F. flavicornis is dark, with only a narrow pale band on the posterior margin of each tergite). The wing of F. lockharti is longer and proportionally narrower, whereas that of F. flavicornis is short and broad. In F. pescotti Tonnoir , in which the setation of the female terminalia is consistent with F. flavicornis , abdominal segment 7 is considerably shorter, and the aedeagus has one terminal tooth and no lateral teeth.

Figures

Figure 1. Fergusonina lockharti: (A) wing; (B) male epandrium; (C) male aedeagus; (D) male aedeagus (detail); (E) female terminalia, dorsal, extended; (F) female terminalia, dorsal, retracted; (G) female terminalia, ventral. Scale bars: D–G, 0.05 mm; B, C, 0.1 mm; A, 1 mm.

Figure 2. Fergusonina lockharti: (A) first instar larva, lateral; (B) second instar larva, lateral; (C) third instar larva, dorsal; (D) third instar larva, lateral; (E) puparium, dorsal aspect. Abbreviations: abs 1–9, abdominal segments 1–9; ceph, cephalic segment; ds, dorsal shield; sa, anterior spiracle; sp, posterior spiracle; ts 1–3, thoracic segments 1–3. Scale bars: A, B, 0.2 mm; C–E, 1 mm.

Figure 3. Fergusonina lockharti: (A) adult head, frontal aspect; (B) tip of male aedeagus; (C) female terminalia, posterior aspect, showing position of setae (arrows, see text); (D) dorsal shield of puparium, anterodorsal aspect; (E) dorsal shield of puparium, anterolateral aspect; (F) galls. Scale bars: C, E, 0.05 mm; B, D, 0.1 mm; A, 0.2 mm; F, 20 mm.