Apiocera striativentris Paramonov, 1953

Ferguson, David J. & Yeates, David K., 2018, Immature stages of the Australian flower-loving fly Apiocera striativentris (Diptera: Apioceridae), Zootaxa 4387 (2), pp. 394-400 : 395-399

Apiocera striativentris Paramonov

( Figs. 2–10 )

Larva ( Figs. 10 A–F ): 38.5-42.0 mm long; 2.9-3.2 mm wide, creamy white in colour; head curved ventrally, partly retractable into prothorax; body cylindrical with lateral, rounded, swollen ridge extending along length of body. Thorax: segment I-III cylindrical, a pair of inconspicuous prothoracic spiracles on posterior and dorsolateral margins of segment I; each with a single, hair-like seta situated medially near ventrolateral margin; metathoracic segment (segment III) with an inconspicuous, minute black vestigial spiracle situated near anterior margin, medially on lateral swollen ridge. Abdomen: segment I posteriorly constricted; segments II-V are conspicuously ‘bead-like’ (as described in English, 1947), segment margins constricted and medial diameter slightly greater than diameter of thoracic and abdominal segments VI-VIII; segments I-VII each with a minute black vestigial spiracle situated medially on lateral swollen-ridge; segments I-VII each with a relatively small, oval shaped ‘creeping welt’ towards posterior margin; prolegs on each side near anteroventral margins of segments II-V; segment VIII with pair of conspicuous posterior spiracles on the dorsolateral surface, near anterior margin; medial surface of posterior spiracle roughly textured with dorsoventrally orientated crescent shaped opening along its anterior margin, outer margin with 63-65 small, oval openings; segment IX half length of segment VIII, posterior margin truncated with narrow ridge; hair-like setae placed on dorsolateral and ventrolateral surfaces ( Figs. 10 A, B ). Head capsule: ( Figs. 10 C, D ): 1 mm wide x 4 mm long (includes metacephalic rod); sclerotised reddish brown and yellow-brown medially; lateral edge with a broad ‘keel’ (term used by English 1 947) for sclerotised lateral extension of epicranium). Relatively short yellow-brown setae on dorsal and ventral surfaces of epicranium and maxilla ( Figs. 10 C, D ); two-segmented maxillary palpus situated on subapical, dorsolateral margin, basal segment length twothirds of its width, apical segment 1.5 x longer than width, apical surface with four processes on anterior surface and slightly larger process medially; pair of mandibular hooks are situated along inner surface of maxillae with labrum medial. Apex of labrum has a pair of small setae, immediately posterior to apex is an elongate, depressed area, along dorsolateral margins are a series of erect setae that extend to posterior margin of the depression ( Fig. 10 F ). Maxilla lacinia broadly covered with numerous small ventrally projected setae. Metacephalic rods darkly sclerotised and supporting a thinly sclerotised membrane medially; tentorial arms anterior half darkly sclerotised, posterior half transparent with broad membranes that extend along its length; a narrow connective membrane extends into head capsule ( Figs. 10 , C–D).

Comments: As the male larva entered the pre-pupal stage it contracted to approximately 60% of its slender, elongated form, and adopted a ventrally curved posture for a few days ( Fig. 5 ) then curved dorsally, remaining that way for few more days before straightening out and pupating. The larvae that resulted in the adult female was more robust than the male larva, not having the distinctive ‘bead-like’ appearance of the anterior abdominal segments. It was probably already a pre-pupa when collected ( Fig. 3 ).

Pupa ( Figs. 6, 8 , 10 , I–O): 19 mm long; greatest width of thorax: 4.5 mm; greatest width of abdomen: 4.8 mm; greatest width of abdominal segment IX: 2mm, (other material examined: 25 mm long; greatest width of thorax: 5 mm; greatest width of abdomen: 6 mm; greatest width of abdominal segment IX: 2.5 mm; cylindrical and straight; head and thorax dark reddish brown, abdomen yellow-brown with conspicuous opalescent sheen. Head: anterior surface with pair of anterior antennal processes with swollen bases and robust spinous apical processes; posterior antennal processes on the lateroventral surface beside the eye sheath have swollen bases, and apices with robust spinous processes projecting posteriorly; distinctive prothoracic spiracles on posterior surface of compound eye sheath margin, extending anteriorly over compound eye sheath. Both anterior mesothoracic spines and posterior mesothoracic spine are elongate and posteriorly directed. Labral sheath (lsh) narrowing posteriorly, extending over proboscidal sheath (prsh) with rugose surface; maxillary sheath (msh) rugose; anterior coxal sheath (asch) rugose; posterior coxal sheath (pcsh) rugose on its margins, relatively smooth medially; leg sheaths 1-3 (lesh 1-3) rugose along lengths; apex of hind leg sheath (lesh 3) reaching the posterior part of abdominal segment II; wing with swollen posterior mesothoracic callosity at wing base; posteroventral extension of wing sheath reaches posterior margin of abdominal segment I. Abdomen: slightly elevated, reddish brown sclerotised spiracles on segments I-VII are situated adjacent to anterior segmental margins and along lateral ridge. Dorsal anterior margin of segment I and posterior margin of segments II-VII are rows of elongate, yellow-brown, bristle-like spines, row curves anteriorly over lateral ridge and medially along dorsal surface; all spines sub-equal in size and length. The total number of spinous processes on abdominal segments are as follows: A1: D: 18, RL: 8, V: absent or obscured, LL: 6; A2: D: partly obscured, RL: obscured, V: 11, LL: 10, A3: D: 32, RL: obscured, V: 18, LL: 12; A4: D: 27, RL: 10, V: 18, LL:11; A5: D: 26, RL: 11, V: 23, LL: 11; A6: D: 24, RL: 9, V: 22; LL: 10; A7: D: 22, RL: 10, V: 21, LL: 10. A8: 57; A9 densely rugulose, without spines.

Comments: The ventral surface of abdominal segment VIII and IX display sexual differences. The male segment VIII is smooth with a continuous, unbroken row of bristle-like spines, and segment IX is shorter in length than that of the female ( Fig. 10 N ). In females the surface of segment VIII is rugose and the row of bristle-like spines has a medial gap ( Fig. 10 O ).

Teneral males ( Fig. 9 ) and females ( Fig. 7 ) possessed full body colours when they emerged. Their opaque wings reached full length quickly and wing veins darkened within 15-20 minutes after emergence. As soon as the wing veins darkened the adults became agitated, walking quickly and flying inside their rearing chamber.

Abbreviations: Larva; abd = abdomen; amsp = anterior mesothoracic spine; ant = antenna; a spr = anterior spiracle; ecr = epicranium; lm = labium; lr = labrum; d mdhk = mandibular hook; mtceph = metacephalic rods; mxl = maxilla lacinia; mx = maxillae; mxp = maxillary palpus; pmc = posterior mesothoracic callosity; prab = abdominal prolegs; p spr = posterior spiracle; thx = thorax; ten = tentorial arm. Pupa: aap, anterior antennal processes; absr = abdominal spiracles; acsh = anteriorcoxal sheath; amsp = anterior mesothoracic spine; cesh = compound eye sheath; lesh 1 = fore leg sheath; lesh 2 = mid leg sheath; lesh 3 = hind leg sheath; lsh = labral sheath; pap = posterior antennal process; pmc = posterior mesothoracic callosity; pcsh = posterior coxal sheath; prsh = area of proboscidal sheath; psh = palpal sheath; pthsr = prothoracic spiracle; pp = posterior processes; wsh = wing sheath.

Material Examined: Larva : Australian Capital Territory (35°19’11.82” S 148°57’23.88” E); Casuarina Sands ; 465m; larvae sieved from bare patches of sand in grassed area: 8 November 2016; D.J. Ferguson; ( ANIC _29:029587). Other material examined: Collection data the same as previous larva; ( ANIC _29:029588), ( ANIC _29:029600); same as previous larvae except collection date : 10 November 2016; (ANIC_29:029601), (ANIC_29:029602), (ANIC_29:029603).

Pupa: Pupal exuvia on pin beneath adult male with label data: Australian Capital Territory (35°19’11.82” S 148°57’23.88” E); Casuarina Sands ; 465m; larvae sieved from bare patches of sand in grassed area: 10 November 2016; pupated: 23 December 2016; emerged: 13 January 2017; ( ANIC _29: 040756).

Additional Material Examined : Pupal exuvia on pin beneath adult female with label data: same as above except sieved: 15 November ; pupated: 28 December 2016 and emerged 19 January 2017, (ANIC_29: 040755). Apiocera maritima larva preserved in ethanol, labelled: New South Wales (35°51’24” S 150°10’50” E), Broulee beach dunes, adjacent to island, 28 September 2015, R .L. & D.J. Ferguson, (ANIC_29: 040767). Six carded female pupal exuvia, labeled: Apiocera maritima Hardy ; Narooma, N.S.W., January 1938 -39. K. English, (ANIC_29: 040757) (ANIC_29: 040758) (ANIC_29: 040759) (ANIC_29: 040760) (ANIC_29: 040761) (ANIC_29:04062). Three carded male pupal exuvia, same as previous, (ANIC_29: 040763) (ANIC_29: 040764) (ANIC_29: 040765). Female pupal exuvia pinned to pith, on pinned adult, Apiocera maxima ; Australia, Kudgee, N.S.W., 16. xii. 1972 . B.P. Moore; on reverse of label: emerged from the sand; (ANIC_29: 040766).

Figures

FIGURE 10. Apiocera striativentris larva and pupa images with details of several morphological characters.A, dorsal view of the male larva, 39.5 mm long; B, lateral view of male larva, 39.5 mm long; C, dorsal view of head capsule, 4 mm long; D, lateral view of head capsule, 4 mm long; E, anterior spiracle of larva, 0.01 mm wide; F, labrum subapical section with pit near apex and setae along the dorsolateral margins; G, posterior view of maxillae palpus; H, posterior spiracle of larva, 0.3 mm widest; I, lateral view of male pupa, 17.5 mm long; J, pupa mask, 7 mm long; K, anterior spiracle of pupa, 0.3 mm wide; L, dorsal row of spinous process on the abdominal segment 5; M, ventral row of spinous process on the abdominal segment 5; N, ventral view of male abdominal segments 8-9, 2.2 mm wide; O, ventral view of female abdominal segments 8-9. [D. J. Ferguson].

FIGURES 1–9. Fig. 1, A view and vegetation of Casuarina Sands, Australian Capital Territory; Fig. 2, Sandy patch free of vegetationthat was sieved, Casuarina Sands; Fig. 3, larvathat resulted inthe adult female in pre-pupa stage. Fig.4, Two larvae sieved from patch of sand; Fig. 5, Pre-pupallarva adopting a ‘C-curve’ position; Fig. 6, The male pupa; Fig. 7, Teneral female with exuvia; Fig. 8, anterolateral view of exuvia [Image: C. Lemann, CSIRO]; Fig. 9, Teneral male with exuvia; [all other images: D. J. Ferguson].scale bar = 2 mm.