Stolas nudicollis ( Boheman, 1850 )

Leocádio, Michele & Mermudes, José Ricardo M., 2019, Description of immatures of Stolas aenea (Olivier, 1790) and Stolas nudicollis (Boheman, 1850) (Coleoptera: Chrysomelidae: Cassidinae: Mesomphaliini), Zootaxa 4545 (1), pp. 61-76 : 66-68

Stolas nudicollis ( Boheman, 1850)

( Figs 39‒58 )

Biology. Eggs were laid directly on leaf surface, without a filamentous stalk. Newly hatching larvae cut a circle around the micropylar area to make their way out of the egg. First instar larvae were gregarious, in contrast with fifth instar larvae, which fed solitary ( Fig. 41 ).

Host plant. Stolas nudicollis individuals fed on Mikania sp. 2 ( Asteraceae ) ( Fig. 38 ) in the field. This is the first host plant record for S. nudicollis .

Egg. Measurements (mm). (n = 11). Length: 1.38‒1.52 (mean = 1.48); width: 0.55‒0.70 (mean = 0.62).

Egg is elongate-oval ( Fig. 39 ), pale-yellow. Chorion surface is densely punctured ( Fig. 40 ). Micropylar area is dark brown elevated, tapering towards the apex.

First instar larva. Measurements (mm). (n = 4). Body length: 1.2‒1.7 (mean = 1.5); body width: 0.8; head width; 0.6; supra-anal process length: 1.1‒1.5 (mean = 1.3).

First instar larvae were fixed after death, which resulted in a darker color and a dry aspect. Besides general body aspect and color, morphological description was not affected.

Body ( Figs 43‒44 ) elongate, slightly flattened dorsoventrally, widest across the metathorax; with 14 pairs of lateral scoli and a pair of supra-anal processes. Integument yellow. Head, pronotum, lateral scoli, supra-anal processes and legs dark brown. Dorsal side of the body with some brown protuberances bearing dark setae. Body surface granulose.

Head ( Fig. 45 ) strongly sclerotized and hypognathous. Endocarina complete, connected to fronto-clypeal suture. Antennae short, set in membranous ring, and two-segmented: first antennomere cylindrical, wider than long; second antennomere cylindrical, longer than wide, with one sensillum at the base; five peg-like sensilla and one long sensory appendix at apex. Vertex with four lateral minute setae. Frons with five rows with very long setae: row Fa with three setae, Fb with five setae, Fc with three setae, Fd with one seta and Fe with two setae. Tempora with three long setae. Six paired prominent stemmata laterally. Clypeus transverse ( Fig. 45 ), five times wider than long, with pair of lateral setae and sensilla. Labrum ( Fig. 47 ) two times wider than long, anterior margin emarginated; with four long setae and two campaniform sensilla medially; two short setae and two campaniform sensilla close to emargination. Epipharynx ( Fig. 48 ) medially with two short setae and many pore-like sensilla; anterior margin with six robust setae on lateral sides and eight short setae on median emargination. Mandibles ( Figs 49‒50 ) strongly sclerotized, with four distinct triangular teeth irregularly serrated and one small proximal serrated protuberance; dorsally with two long setae at the base and two medially sensilla. Maxillae and labium ( Fig. 46 ) connate. Maxillary palpi two-segmented, with a distinct palpiger. First palpomere with two setae and one campaniform sensillum ventrally, second palpomere conic and rounded at apex, with group of apical sensilla, one setae and one campaniform sensillum dorsally. Mala and lacinia not distinctly delimited from palpiger. Palpiger with two long setae and two campaniform sensilla ventrally. Lacinia on dorsal side of palpiger bearing spines at apex. Mala with nine stout, pointed setae and one campaniform sensillum. Paired stipes each with three long, pointed setae. Labial palpi one-segmented with group of apical sensilla and one campaniform sensillum laterally. Prementum with six setae and four campaniform sensilla. Postmentum with two pairs of short setae and a pair of long setae.

Thorax. Pronotum with one pair of lateral prominent spiracles and three rows of very long setae, disposed as 6- 6-10. Mesonotum with two rows of protuberances: first row with eight protuberances with ten setae disposed as 2- 1-1-1-1-1-1-2; second row with six protuberances with ten setae disposed as 2-1-2-2-1-2. Metanotum with the same pattern of setae. Thoracic sternites with a few sparse and very long setae. Legs stout, three-segmented; coxa with at least four very long setae and five short setae at base. Femur strongly sclerotized, with at least seven long setae, one short seta and five campaniform sensilla at base. Tibiotarsus with single claw at the apex, with numerous stout, pointed setae around claw.

Lateral scoli unbranched, with numerous long pointed setae along its length and one seta at apex. Four pairs of scoli on prothorax, one pair on mesothorax, one pair on metathorax and one pair on abdominal segments I‒VIII. Scoli of pairs X‒XI shortest, XIII‒XIV longest, shorter than the supra-anal processes.

Abdomen with ten segments. Tergites I‒VIII with one pair of prominent lateral spiracles, their diameter slightly decreasing posteriorly. Each abdominal tergite bearing a row of setae: tergite I with 12 setae, tergites II‒VIII with ten setae. Ventrites with numerous long setae disposed in rows. Supra anal-processes unbranched, with numerous long setae; apex membranous and unarmed.

Last instar larva. Measurements (mm). (n = 2). Body length: 12.1‒13.7 (mean = 12.9); body width: 7.3; head width: 2.5‒2.6 (mean = 2.55); supra-anal process length: 2.3‒2.4 (mean = 2.35).

Body ( Figs 51‒52 ) oval, flattened dorsoventrally; widest across the metathorax and first abdominal segment; with 14 pairs of lateral scoli and a pair of supra-anal process. Dorsal side pale yellow, with brown spots uniformly distributed. Thorax dorsal side with lateral pale brown spots. Pronotum with one spot on anterior margin and two spots on posterior margin. Mesonotum with four medial spots. Metanotum with four large spots. Abdominal tergites I‒VI with similar pattern of spots: medially with six small spots and laterally one small and one large. Head, legs and lateral scoli brown, except for pair of scoli XIV, yellow. Pair of supra-anal processes yellow. Thoracic sternites pale yellow. Abdominal sternites II‒IV pale yellow with lateral brown spots, sternites V‒VIII brown.

Head ( Fig. 53 ) strongly sclerotized, hypognathous and dorsally covered by the pronotum, visible only ventrally. Endocarina complete, connected to fronto-clypeal suture. Antennae short, set in membranous ring, and two-segmented: first antennomere cylindrical, wider than long, with a short seta on the internal margin; second antennomere cylindrical, longer than wide with one seta at the base; five peg-like sensilla and one sensory appendix at apex. Vertex with four lateral minute setae. Frons with about 44 pairs of setae distributed uniformly. Tempora with five long setae. Six lateral prominent stemmata, two grouped pairs positioned lateral-frontal and one pair ventral-lateral. Clypeus transverse ( Fig. 53 ), 5.2 times wider than long, with pair of lateral setae. Labrum ( Fig. 55 ) two times wider than long, anterior margin emarginated; with four long setae and two campaniform sensilla medially; two short setae and two campaniform sensilla close to emargination. Epipharynx ( Fig. 56 ) medially with two short setae and two groups of nine pore-like sensilla; anterior margin with six robust setae on lateral sides and seven (it is possible one seta is missing, since the number of setae in the emargination is always even) short setae on median emargination. Mandibles ( Figs 57‒58 ) strongly sclerotized, with four distinct triangular teeth slightly serrated and one small proximal serrated protuberance; dorsally with two long setae and one sensillum. Maxillae and labium ( Fig. 54 ) connate. Maxillary palpi two-segmented, with a distinct palpiger. First palpomere with two setae and one campaniform sensillum ventrally; second palpomere conic, with group of apical sensilla, one seta and one campaniform sensillum dorsally. Mala and lacinia not distinctly delimited from palpiger. Palpiger with two long setae and one campaniform sensillum ventrally. Lacinia on dorsal side of palpiger bearing spines at apex. Mala with nine stout, pointed setae and one campaniform sensillum. Paired stipes each with three long, pointed setae and one campaniform sensillum. Labial palpi one-segmented with group of apical sensilla and one campaniform sensillum laterally. Prementum with four long setae, two short setae and four campaniform sensilla. Postmentum with a pair of short setae and three pairs of long setae.

Thorax. Pronotum with one pair of lateral prominent spiracles and numerous short setae: 12 on anterior margin, six on each lateral margin and 14 on posterior margin. Mesonotum with one seta on each lateral side and two rows of setae: anterior row with eight setae and posterior row with six setae. Metanotum with one seta on each lateral side and two rows of setae: anterior row with eight setae and posterior row with 16 setae. Pro-, meso- and metasternum with numerous setae arranged in four groups: two lateral and two medial. Legs stout, threesegmented; coxa with numerous long setae; femur strongly sclerotized, with short and long setae distributed uniformly; with two very long setae and five campaniform sensilla at the base. Tibiotarsus with single claw at the apex, with numerous stout pointed setae around claw.

Lateral scoli unbranched, with numerous spiniform projections bearing long pointed setae. Four pairs of scoli on prothorax, one pair on mesothorax, one pair on metathorax and one pair on abdominal segments I‒VIII. Scoli of pairs IX‒X shortest; V, XII‒XIII longest, longer than the supra-anal processes.

Abdomen with ten segments. Tergites I‒VIII with one pair of prominent lateral spiracles, their diameter slightly decreasing posteriorly, pair of tergite VIII extremely small. Abdominal sternites I‒VI with many setae distributed uniformly, sternites VII‒VIII with fewer setae. Supra anal-processes unbranched, with smooth surface, many short setae at the base; thickened basally and tapering towards apex; apex unarmed.

Specimens examined. BRAZIL, Rio de Janeiro, Cachoeiras de Macacu, Reserva Ecológica de Guapiaçu, Brown Trail (22°26'50,7" S, 42°46'17,6" W). Eggs : 13 collected on 10.x.2013, Leocádio, M. col. ( DZRJ1106 ). First instar larvae: 4 collected on 10.x.2013, Leocádio, M. col. ( DZRJ1107 ) (one dissected). Last instar larvae: 1 collected on 05.vii.2014, Leocádio & Mermudes col. ( DZRJ1108 ) (only head dissected) .

Figures

FIGURES 38–42. Stolas nudicollis (Boheman, 1850) and host plant. (38) Host plant Mikania sp. 2; (39–40) egg, habitus and detail of chorion surface; (41) last instar larva with faecal shield; (42) Adults male and female in copula.

FIGURES 43–50. Stolas nudicollis (Boheman, 1850), first instar larva. (43–44) Habitus, dorsal and ventral; (45) head; (46) maxillae and labium; (47) labrum; (48) epipharynx; (49–50) mandible, dorsal and ventral.

FIGURES 51–58. Stolas nudicollis (Boheman, 1850), last instar larva. (51–52) Habitus, dorsal and ventral; (53) head; (54) maxillae and labium; (55) labrum; (56) epipharynx; (57–58) mandible, dorsal and ventral.