Copestylum

Rotheray, Graham E., Marcos-García, Maria-Angeles, Hancock, Geoff, Pérez-Bañón, Celeste & Maier, Chris T., 2009, Neotropical Copestylum (Diptera, Syrphidae) breeding in Agavaceae and Cactaceae including seven new species, Zoological Journal of the Linnean Society 156 (4), pp. 697-749 : 700-701

COPESTYLUM REARED FROM AGAVES AND CACTI

Diagnosis

Larva: Length, 4–50 mm long; subcylindrical in crosssection; truncate anteriorly, usually tapering posteriorly because of narrowing of the anal segment ( Figs 20–27 ). Mouthparts saprophagous i.e. mandibles and mandibular lobes inverted into the oral cavity, attached to the pseudocephalon and forming a filter ( Hartley, 1963; Rotheray & Gilbert, 2008). Cephapharyngeal head skeleton varying in relative lengths of the dorsal and ventral cornua and sclerotization of the vertical plate ( Figs 35–43 ). Dorsal cornua generally rounded apically and only slightly inclined backwards, always shorter than ventral cornua. Mandibles and mandibular lobes variable in size. Dorsal bridge present. Ventral cornu with or without dorsal apodeme ( Figs 42, 43 ). Pharyngeal grinding mill consisting of two opposable sclerotized plates ( Hartley, 1963; Roberts, 1969) sometimes present at the distal apex of the ventral cornua ( Figs 39 , 43 ). Prothorax with well-developed lateral lips and anterior fold. Anterior fold coated in transverse rows of backwardly directed spicules (sclerotised setae). Thorax with varying arrangements and types of setae and spicules ( Figs 28–34 , 54 ). Mesothoracic prolegs present with one to three rows of crochets, rows either transverse or forming ‘U’ or ‘W’ shaped rows. Prolegs on abdominal segments 1–3 or 1–6 with two or three transverse rows of crochets. Abdomen coated in vestiture comprising setae or spicules of various shapes and densities which generally becomes longer towards the anal segment and shorter on the ventral surface. Anal segment divided dorsally into two sections; the anterior section bearing two pairs of lappets (fleshy projections with an apical sensillum and surrounding setae) usually of unequal length and the posterior section bearing a single pair of lappets ( Figs 20–27 ). Base of first (anterodorsal) pair of lappets with an additional short, sometimes inconspicuous fleshy projection bearing an apical sensillum and surrounding setae. Anal segment elongate, longer than sixth abdominal segment, or contracted, shorter than sixth abdominal segment. Posterior breathing tubes fused into a single sclerotized structure variable in length and ornamentation ( Figs 44, 46 , 60, 61 , 68, 70 ). Close to the apex of the breathing tube a shallow to deep transverse ridge (TR) ( Figs 44 , 58, 60, 61 ), section of breathing tube above TR to apex (AP) always with a different surface ornamentation than below: TR from smooth and shiny to being punctured. Spiracular plates usually level each with three pairs of curved to convoluted openings and four groups of interspiracular setae, setae often missing ( Figs 59 , 63 , 70 ). Pupal breathing tubes variable in length, shape, ornamentation, and arrangement of spiracular openings, with openings almost reaching base, concentrated at the apex or on the underside ( Figs 47–53 ).

Taxonomic notes: Characters that distinguish larval Volucellini (including Copestylum ) from other syrphid larvae are the presence of inverted mouthparts and the anal segment divided into two sections with the anterior section bearing two pairs of lappets, the first pair of which has an additional lateral sensillum. Copestylum larvae may be separated from other volucellines by the first two pairs of lappets, which are unequal in length. Rarely are these lappets equal in length but if so, then the lappets are smooth and lack a coating of setae. The 42 species reared from agaves and cacti in this study divide into ten morphological groups ( Table 1) and are diagnosed below.

Figures

Figures 20–22. Third stage larval Copestylum, whole larva, head to the right; scale bar = 6 mm. 20, Copestylum satur; 21, Copestylum tetetzoi sp. nov.; 22, Copestylum vittatum.

Figures 23–24. Third stage larval Copestylum, whole larva, head to the right; scale bar = 6 mm. 23, Copestylum haagii; 24, Copestylum hoya.

Figures 25–27. Third stage larval Copestylum, whole larva, head to the right; scale bar = 7 mm. 25. Copestylum apiciferum; 26, Copestylum isabellina; 27, Copestylum sica.

Figures 35–40. Third stage larval Copestylum, head skeleton, apex to the left, scale bar = 1.4 mm. 35, Copestylum hambletoni; 36, Copestylum vittatum; 37, Copestylum fraudulentum; 38, Copestylum marginatum; 39, Copestylum haagii, 39A, whole head skeleton; 39B, grinding mill, ventral view; 40, Copestylum hoya.

Figures 41–43. Third stage larval Copestylum, head skeleton, apex to the left, scale bar = 1.4 mm. 41, Copestylum dispar; 42, Copestylum apiciferum; 43, Copestylum latum.

Figures 28–34. Third stage larval Copestylum, body vestiture, black areas represent extent of sclerotization; scale bar = 1 mm. 28, 31, and 34, Copestylum quadratum, 28, long fine setae from the dorsum of the metathorax; 31, crochets from proleg on first abdominal segment, larger crochet = primary; smaller crochet = secondary; 34, branched setae from base of lateral lips; 29–30, Copestylum isabellina, 29, short, broad setae from the dorsum of the metathorax, 30, spicules from the anterior fold of the prothorax; 32, Copestylum hambletoni, broad based setae from dorsum of mesothorax; 33, Copestylum multipunctatum sp. nov., triangular shaped setae from dorsum of the anal segment.

Figures 54–57. Puparia of Copestylum, scanning electron photomicrographs, scales as indicated on images, 54, Copestylum pictum, dorsum of prothoracic shield length 3.5 mm; 55, Copestylum spinigera, pupal spiracles, ventral view length 1.12 mm; 56, 57, Copestylum hambletoni, pupal spiracle length 1.3 mm; 56, ventral view; 57, dorsal view. af, apex of anterior fold with spicules; as, anterior spiracle; lf, longitudinal fold; s, spicule groups on anterodorsal margins of mesothorax and metathorax; P, prothorax; Ms, mesothorax; Mt, metathorax.

Figures 44–47. Puparia of Copestylum, scanning electron photomicrographs. 44, Copestylum florida, posterior breathing tube (prp), dorsal view width at TR = 0.3 mm; 45–47, Copestylum vittatum, 45, prp, apical view width 0.2 mm; 46, prp, dorsal view width at TR = 0.5mm; 47, pupal spiracles, whole view from above scale as indicated on images.

Figures 58–61. Puparia of Copestylum, scanning electron photomicrographs, scales as indicated on images, 58, 59, Copestylum spinigera; 58, posterior breathing tube (prp), dorsal view width at TR = 0.87 mm; 59, prp, apical view width = 0.8 mm; 60, Copestylum cockerelli, prp dorsal view width at TR = 1.5 mm; 61, Copestylum hambletoni, prp, dorsal view width at TR = 1.45 mm.

Figures 68–73. Puparia of Copestylum, scanning electron photomicrographs, scales as indicated on images. 68, 70, Copestylum macrocephalum; 68, posterior breathing tube (prp), dorsal view width of TR = 1.3 mm; 70, prp, apical; 71, Copestylum posticum; pupal spiracles, dorsal view length = 0.93 mm; 69, 72–73, Copestylum isabellina; 69, prp, dorsal view width at TR = 1.1 mm, 72, pupal spiracles, ventrolateral view length 0.82 mm; 73, spiracular openings, apical and lateral views.

Figures 62–65. Puparium of Copestylum dispar, scanning electron photomicrographs, scales as indicated on images. 62, posterior breathing tube (prp), dorsal view width at TR = 1.0 mm; 63, prp, apical view width = 0.9 mm; 64, pupal spiracle, ventral view length 1.12 mm; 65, pupal spiracle, dorsolateral view.