Stilobezzia punctulata Lane

Cazorla, Carla G., Diaz, Florentina, Spinelli, Marino Gustavo R. & Ronderos, María M., 2013, New contributions to the knowledge of the immatures of Stilobezzia punctulata Lane and Stilobezzia fiebrigi Kieffer (Diptera: Ceratopogonidae), Zootaxa 3745 (1), pp. 93-99 : 96-98

Stilobezzia punctulata Lane

( Figs. 7–12 , 16–18 )

Stilobezzia punctulata Lane 1947: 204 (female; Brazil)

Stilobezzia (Stilobezzia) punctulata: Lane & Forattini, 1958: 220 (male; Brazil, Panama); Wirth 1974: 45 (catalogue of Neotropica1 species); Borkent & Wirth, 1997: 112 (catalogue of World species); Borkent & Spinelli, 2000: 54 (catalogue of Neotropical species); Cazorla & Marino, 2004: 75 (pupa, Mexico, Colombia, Peru, Bolivia [misident]); Borkent & Spinelli, 2007: 87 (catalogue of Neotropical species); Borkent, 2012 (catalogue of World species); Torreias et al., 2013: 10 (distribution).

Description of fourth instar larva ( Figs. 7–12 , 16–18 ). Head capsule yellowish brown, elongated, cylindrical; chaetotaxy as in Figs. 7–9 ; HL 0.431 mm (SEM), 0.476 mm (BCM); HW 0.169 mm (SEM), 0.372 mm (BCM); HR 2.55 (SEM), 1.28 (BCM); SGW 0.140 mm (SEM), 0.312 mm (BCM); SGR 1.21 (SEM), 1.19 (BCM). Antennae well developed, stout ( Figs. 7–9 ). Labrum ( Figs. 8–10 ) as long as wide; palatum ( Figs. 9–10 ) with three pairs of sensilla styloconica on its anterior edge, the inner one longer; two pairs of sensilla trichoidea on mesal portion, anterior one stouter; one pair of sensilla campaniformia inmediately underneath; well developed, long, pointed scopes ( Fig. 10 ); well developed messors ( Fig. 10 ), lateral to scopes; palatal bar ( Fig. 10 ) present, tongue -shaped. Mandible ( Figs. 7, 9–10 , 18 ) stout, curved, strongly sclerotized; apical tooth large, two submedian teeth, anterior one small, posterior one stouter, recurved back; basal portion with long, thin seta and a pore; fossa mandibularis on ectal surface, MDL 0.10 mm. Maxilla ( Figs. 7, 9–10 ) sclerotized, galeolacinia ( Fig. 10 ) with lacineal sclerite 1 with long thin setae, lacineal sclerite 2 with long, stout seta; maxillary palpus ( Fig. 10 ) cylindrical with 3–4 apical papillae. Hypostoma ( Figs. 7, 10 ) nearly straight, smooth. Epipharynx ( Fig. 16 ) massive; ventral comb massive, its posterior margin irregular with 7 pointed teeth, mesal one smaller; other comb with numerous thin teeth superimposed; nearly straight, sclerotized medial sclerite; lateral arms stout, sclerotized with elongated lateral curtains; LAW 0.066 mm, DCW 0.025 mm; dorsal comb with 9 stout teeth. Hypopharynx ( Fig. 17 ) elongate, posterior end arms thick, without hypopharyngeal fringe. Thoracic pigmentation pale brown. Caudal segment ( Fig. 12 ), chaetotaxy as in Fig. 11 ; four pairs of stout, long setae and two pairs of long, thinner ones; long, stout setae "o" 0.500 mm (SEM), 0.687 mm (BCM); CSL 0.572 mm (SEM) 0.70 mm (BCM); CSW 0.140 mm (SEM) 0.200 mm (BCM).

Bionomics. The larvae of Stilobezzia punctulata were collected from the bottom of a temporary lagoon, associated to hydrophytes. They showed slow, undulating swimming motion, and lasted six days to reach the pupal stages under laboratory rear conditions; the only pupa that reached the adult stage took 10 days to emerged.

Taxonomic discussion. The larva of Stilobezzia punctulata shows some of the previously listed features of carnivorous-predatory larvae for S. fiebrigi . However, the mandible of S. punctulata is larger and more sclerotized than the one of S. fiebrigi ; the head is elongated and cylindrical; the hypostoma is nearly straight and smooth, lacking the mesal elevation flanked by serrate margins; and the lateral arms of the hypopharynx are not connected posteriorly. Stilobezzia punctulata also presents some characters that have been observed in larvae of other genera that bread in clean water of tree holes, such as the presence of lateral curtains in the lateral arms of the epipharynx. Finally, with regard to the very long setae of the caudal segment of this species, Mullen & Hribar (1988) suggested that they may function to amplify the body oscillation and to increase the larval speed in water, enabling to capture prey and/or to avoid predators.

Material examined: Argentina, Corrientes, Estación Biológica Corrientes (EBCo), 27º32'51.8'' S, 58º40'44.8'' W, 52 m, 26-XI-2010, P. Marino, 1 male with larval and pupal exuviae.

Material examined by SEM: same data, 2 larvae (instar IV).

Figures

FIGURES 7 – 12. Stilobezzia punctulata Lane, four instar larva. 7, head capsule ventral view (chaetotaxy); 8, head capsule, dorsal view (chaetotaxy); 9, head capsule, anteroventral view; 10, head capsule, anteroventral view, detail of mouthparts; 11, caudal segment, lateral view; 12, entire larva. Scale: 0.05 mm.

FIGURES 13 – 18. 13 – 15, Stilobezzia fiebrigi. 13, epipharynx, dorsal view; 14, hypopharynx, ventral view; 15, mandible, lateral view; 16 – 18, Stilobezzia punctulata. 16, epipharynx, dorsal view; 17, hypopharynx, ventral view; 18, mandible, lateral view. Scale: 0.05 mm.