Acentroptera cf. tessellata Baly, 1958

Albertoni, Fabiano F. & Casari, Sônia A., 2017, The natural history and morphology of two bromeliad associated hispines from Brazil: Acentroptera basilica Thomson, 1856 and A. cf. tessellata Baly, 1958 (Coleoptera: Chrysomelidae: Cassidinae: Sceloenoplini), Zootaxa 4243 (3), pp. 521-543 : 531-539

Acentroptera cf. tessellata Baly, 1958

( Figs 53–95 )

Description of first instar larva ( Figs 53–63 , 88, 89 ). Length: 2.5 mm.

Coloration yellowish-white; head ( Figs 55, 56 , 62, 63 ) yellowish with anterior margin of head capsule, mandibles, sagittal line, hypostomal rods and stemmata dark–brown or brown. Prothorax with yellowish rectangular area dorsally and ventrally. Legs ( Figs 60 , 63 ) partially yellowish with tarsunguli dark-brown. Thorax and abdomen with granulated dorsal areas. Antennae ( Figs 58, 59 , 62, 63 ) with 3 elongate antennomeres: basal bearing one short seta and one campaniform sensillum ventrally, near base; median shorter than basal, bearing one short seta ventrally, near middle, 2 stout and short setae dorsally, near apex, and one membranous sensorial appendix at apex, shorter than distal antennomere; distal, shorter and narrower than previous, bearing at apex 3 stout and short setae, one longest.

Head and mouthparts similar to “mature” larva.

Pronotum dorsally granulated in anterior band and in median posterior elliptical area; ventrally each side with granulated anterior fold. Prothoracic spiracle at apex of a tubular projection. Mesonotum grooved transversely slightly granulated on each extremity. Metanotum and segments I–VII grooved transversely, each side of groove granulated. Segments I–VIII with one lateral median elongate projection on each side, each with 2 setae at apex and 2–3 setae near base; segments I–VII with a tubular lateroanterior projection on each side, with spiracular opening at apex; spiracular opening elliptical. Segment IX ( Fig. 61 ) narrow than previous, almost as long as wide, with V-shaped apex and two dorsally placed spiracular openings, innerly to distal angles; distal angles setose; segment X ( Fig. 54 ) reduced, rounded, placed ventrally.

Description presumably mature larva ( Figs 64–81 ).

Length: 10–11 mm (n=2)

Body ( Figs 64–68 ) elongate, wide, strongly dorso-ventrally flattened; abdomen with lateral elongate projections. Coloration cream after fixation; head strongly sclerotized, yellowish with frons darker; mandibles, endocarina and hypostomal rods brown; pronotum yellowish–cream; legs yellowish, partially brown; tarsunguli brown. Body almost glabrous; short setae present laterally in whole length. Thorax and abdomen with granulated elliptical areas; smaller areas ventrally.

Head ( Figs 64 , 66–72 ) prognathous, narrower than prothorax, strongly dorsoventrally flattened, partially retracted into prothorax; epicranial stem absent; median endocarina well-developed, extending between frontal arms; frontal arms V-shaped. Six black stemmata on each side: 2 lateroanterior, 2 dorsal and 2 ventral. Frons with 8 pairs of tiny setae: one pair on each side near anterior margin, an inclined row with 3 setae on each side of endocarina, one pair on each side near base and one pair on sagittal line; each epicranial half with 10 setae: 4 setae near lateral margin, one near frontal arm and a longitudinal row with 5 setae near middle. Hypostomal rods welldeveloped. Frontoclypeal suture indistinct. Antennae ( Figs 69, 70 , 73, 74 ) with 3 elongate antennomeres: basal antennomere with one campaniform sensillum dorsally and one ventrally; median antennomere bearing one ventral short and stout seta near middle, one membranous, cupuliform, sensorial appendix at apex, and the distal antennomere; sensorial appendix as long as distal antennomere; distal antennomere reduced, a half width of median antennomere, inserted latero-internally at apex, side by side with sensorial appendix, bearing at apex 3 short and stout setae. Labrum ( Figs 69 , 75 ) band-like, strongly emarginated medially with distal angles widely rounded; one pair of tiny setae on each side and a dense fringe of setae at anterior margin, shorter in middle. Epipharynx ( Fig. 76 ) densely setose near anterior margin; microspined and with stout setae near middle; one short seta and one pair of campaniform sensilla on each side, near base; two basal campaniform sensilla in middle. Mandible ( Figs 77, 78 ) with lateral margin sinuous on basal half; 3 dorsal and 3 ventral subapical, rounded teeth; one mesobasal stout rounded tooth; one lateroventral tiny seta near base. Maxilla ( Figs 70 , 72 , 80 ): cardo triangular and reduced; palpus indistinguishable; stipes elongate with lateral margin rounded, narrowed at base, with 3 tiny setae laterally; mala triangular, partially sclerotized, densely setose, brush-like near apex and with 4 tiny setae near base. Labium elongate; palpi indistinguishable; prementum with sclerotized transverse band, darker in one triangular area on each side, bearing two tiny setae at base; ligula densely setose, brush-like on distal half; setae surpassing anterior margin; postmentum elongate with 3 pairs of tiny setae. Hypopharynx ( Fig. 79 ) densely setose anteriorly; basal half slightly sclerotized with 2 small lateroanterior sclerites on each side, and 2 larger, rounded, basal sclerites near midde.

Thorax. Prothorax wider than long, longer than mesothorax; fore angles widely rounded; lateral margins almost straight; anterior margin with narrow granulated band; basal region with granulated narrow elliptical band near middle; short setae laterally. Meso- and metathorax band-like, almost of same size; each with placed laterodorsally small rounded projections, with 3–4 setae; mesothorax with laterodorsal anterior rounded spiracle located at apex of tubular projection ( Fig. 68 ); meso- and metathorax dorsally each with two transverse and narrow granulated band with a transverse groove in middle, and ventrally with one small elliptical granulated area on each side.

Legs ( Figs 64 , 67, 68 , 81 ) widely separated, located ventrolaterally; slightly sclerotized, short, robust and 4- segmented; coxa short, band-like, with 3 short setae; femur and trochanter fused, wider than long, with 4 short setae near anterior margin and 5 near base; tibia wider than long with row of sparse setae near anterior margin and one near base; tarsungulus sclerotized with lateroexternal seta at base.

Abdominal segments I–VIII ( Figs 65–68 ) with a lateral median elongated projection with one seta at apex; last segment shorter and more robust; segments I–VII each with one laterodorsal tubular projection with spiracular opening at apex; segments I–VII dorsally with a transverse groove with one narrow band of granulations anteriorly and 2 posteriorly; median band short and/or fused to posterior, forming an elliptical granulated area; ventrally with transverse furrow and elliptical granulated area; granulated area shorter posteriad; segment VIII shorter than previous, spiracle absent; segment IX narrower than previous, sclerotized, elongate, narrowed posterad, with distal margin emarginated, with 2 dorsal spiracular openings, innerly to distal angles. Segment X reduced, ventral, partially sclerotized with distal margin bilobed.

Description of pupa based on pupal exuvia ( Figs 82–86 ).

Head and prothorax lost. Abdomen elliptical, wider on segments III–V; setae on lateral projections and on granulations. Segments I–VIII each with two lateral projections on each side: one short triangular, with sclerotized inner angle and one distal seta, and the second long with sclerotized apex, bearing one seta apically and one sclerotized projection ventrally.

Dorsally, integument with small rounded tubercles, densely granulated with one short seta at apex (setae and granules not represented on Fig. 83 ); segment I with a few tubercles; segments II–VII with two transverse rows of tubercles; segment VIII with one transverse row and segment IX with two tubercles in middle, each with one basal seta. Spiracular openings at apex of dorsolateral tubular projection of segments III–IV; segment V with spiracular opening elongate, horn-like; a pair of rounded spiracular openings near base of segment IX. Ventrally, segments VII–VIII with some microspines near middle. Segment IX narrow, slightly sclerotized, with two apical broad lobes with strongly sclerotized teeth. Segment X reduced, placed ventrally.

Material examined. Brazil. Bahia: Serra Grande, Uruçuca (Faz. Modus Vivendi), 21–27.IX.2015, F.F. Albertoni & M. A. Ulysséa col., 1 first instar larva, 2 (1 dead) presumably mature larvae; 3 exuviae of head, 1 pupal exuvia.

Geographical distribution. Brazil (Bahia and Rio de Janeiro) (present work and Staines 2014).

Biology of Acentroptera cf. tessellata Baly, 1958 ( Figs 87–95 )

The host plant of A. cf. tessellata is here reported for the first time, and the feeding habit of the adults of this species is similar that of A. basilica , although the host plant is Vriesea sp. Adults were searched for four consecutive nights and were not seen feeding, or on the freely open surface of leaves; they were deeply hidden among leaf bases of the rosette. During the hottest periods of the day they were also hidden among leaf bases, and were frequently seen feeding around 15:30 h. While feeding, adults stayed motionless and clinging to leaf surface when bothered, but would display tanatosis if released from leaf surface. When turned upside down on a flat surface, they efficiently turn to an upright position. Using the head and legs, the beetle managed to lean the body to one side and with the legs, hold the surface and pull the body. In this way the tibial-femur join help the movement provoking a larger body inclination, enabling the other side legs to hold the surface and definitely impulse the whole body to the upright position (this behaviour is illustrated on Figs 90–94 ). Ants that walked on bromeliad leaves were seen interacting with adults few times including antennal perception (apparently scanning for chemical and tactile cues) of the beetle. Those were relatively quick interactions and in all cases ants seemed to have “friendship” with the beetles ( Fig. 95 ).

Eggs of A. cf. tessellata were laid alone (three observation) or in sequence of three to four eggs (four observations) on scrapped areas of the leaf surface ( Fig. 87 ). First instar larva hatched and immediately started mining the leaf. When uncovered by first leaf tissue layer, the ventral side of the first instar larva was turned to the thinner side of the leaf tissue corresponded to the adaxial leaf face ( Fig. 88 ).

Figures

FIGURES 53 – 61. Acentroptera cf. tessellata Baly, 1958. First instar larva: 53, 54, habitus (dorsal, ventral); 55, 56, head (dorsal, ventral); 57, clypeus; 58, 59, left antenna (dorsal, ventral), 60, leg; 61, IX segment dorsal.

FIGURES 62 – 65. Acentroptera cf. tessellata Baly, 1958. Fist instar larva: 62, 63, habitus (dorsal, ventral). Later instar: 64, head, thorax and first abdominal segment (lateral); 65, IX segment dorsally.

FIGURES 66 – 70. Acentroptera cf. tessellata Baly, 1958. Later instar larva: 66 – 68, habitus (dorsal, ventral and lateral); 69, 70, head and prothorax (dorsal, ventral).

FIGURES 71 – 76. Acentroptera cf. tessellata Baly, 1958. Later instar larva: 71, 72, head (dorsal, ventral); 73, 74, left antenna (dorsal, ventral); 75, clypeus and labrum; 76, epipharynx.

FIGURES 77 – 81. Acentroptera cf. tessellata Baly, 1958. Later instar larva: 77, 78, mandible (dorsal, ventral); 79, hypopharynx; 80, maxilla and labium; 81 leg.

FIGURES 82 – 86. Acentroptera cf. tessellata Baly, 1958. Pupal exuvia: 82, 83, habitus (ventral, dorsal); 84, prolongation of lateral abdominal segment; 85, 86, apex of abdomen (ventral, dorsal).

FIGURES 87 – 95. Acentroptera cf. tessellata Baly, 1958. Eggs: 87, row of three viable eggs near leaf border. First instar larva inside mine: 88, on “ natural position ” (upside down); 89, dorsal view. Adults: 90, on tanatosis; 90 – 94, righting behaviour: 90, beetle on tanatosis; 91, beetle leaning the body to its right side (the right side legs are now the nearest to de surface); 92 – 93, using the other side legs and the tibio – femur join to pull the body; 94, turned to upright position; 95, ant and adult interaction while the last feeds.