Yingaresca holosericea, (BOWDITCH) (Bowditch)

Duckett, Catherine N. & de Azevedo Moura, Luciano, 2002, First Descriptions Of Immature Stages Of Yingaresca Holosericea (Bowditch) (Coleoptera: Chrysomelidae: Galerucinae) And Notes On Their Biology, The Coleopterists Bulletin 56 (2), pp. 161-169 : 163-167

Description of Immatures

Mature Larva ( Figs. 1A–E , 2A–G ).

Morphometrics: length 4.2–7.0 mm; width 1.0– 2.1 mm.

Habitus. Body, ( Fig. 1A ) eruciform, setose, weakly to strongly arched in preserved specimens; head hypognathous, well sclerotized. Color creamy white with a piceous longitudinal dorsal stripe on either side of midline formed by dorsal sclerites; ventral surface cream, head and legs piceous.

Head ( Fig. 2A–B ). Ovoid, evenly rounded. Epicranial suture distinct, Y­shaped; coronal stem about 1/4 length of head; frontal arms slightly arched; endocarina distinct, extending from base of frons to vertex about midway up the coronal stem. Frons bearing 3 pairs of prominent setae, 1 pair near lateral margin of clypeus, 1 pair near clypeal midline, 1 pair near midline, slightly dorsal to antenna with 1 pair of dorsal placoid sensilla. Each epicranial half bearing 8 setae (5 dorsal, 3 ventrolateral) and 4 sensilla near coronal stem, 3 placoid, 1 peg­like. Stemma rounded; 1 placoid sensillum ventromedial to stemma. Antenna ( Fig. 2G ) small, retractile, 2­segmented; basal segment transverse, bearing 4 round sensilla and 2 peg­like sensilla on membranous apex, 2nd segment conical. Clypeus free, transverse, bearing 3 pairs minute setae evenly distributed across width, lateral most seta dorsal to small placoid sensillum, apical margin straight. Labrum ( Fig. 2D ) free, slightly emarginate apically, bearing 2 pairs stout setae. Epipharyx bearing 7 pairs of spiniform submarginal setae, 1 pair extending past margin; bearing 10 pairs campaniform sensilla and 1 pair peglike sensilla (near midline), midline with abundant microtrichia. Mandible ( Figs. 2A, 2F ) palmate, 5­dentate, 1 small dorsal seta, 1 placoid sensillum and penicillus composed of straight setae. Maxilla ( Fig. 2C, 2E ) lightly sclerotized; cardo transverse, glabrous: stipes elongate, bearing 3 long setae. Galea and lacinia difficult to see if not spread; galea rounded separated from lacinia, bearing 5 spiniform setae and 2–3 slender setae apically, 2 setae subapically; lacinia flattened, bearing 4–5 spiniform setae apically; maxillary palpi 4­segmented, basal segment bearing 3 setae, segments 2 and 3, bearing placoid sensillum, segment 3 bearing short lateral seta, apical segment bearing 1 short seta dorsally, 1 placoid sensillum and 1 lateral groove­shaped sensillum bearing peg­like structure at base. Labium ( Fig. 2C ) mostly membranous with a sclerotized area posteriorly, bearing 2 large setae, and basally 1 pair of large placoid sensilla; ligula broad with 3 pairs of short stout setae; labial palpi 2­segmented, apical segment bearing 1 elongate groove laterally with large peg­like sensillum basally, placoid sensillum ventrally and apex bearing group of small peg­like sensilla.

Thorax. Pronotum ( Fig. 1E ) dorsally flattened, shield­like, lightly melanized, midline not melanized, each half bearing 8 pairs of setae, epipleural tubercle bearing 3 long setae and prehypopleural tubercle bearing 3 short setae. Mesothorax bearing small annular spiracle. Mesonotum and metanotum same width as pronotum, both with a transverse median groove forming 2 plicae and an identical arrangement of sclerites, each bearing: 1 medial interior prescutal sclerite with 2 pairs setae, 1 exterior prescutal sclerite with 1 seta, epipleural tubercle prominent, bearing 4 long setae, posterior parascutal sclerite bearing 2 setae, exterior scuto­scutellar sclerite bearing 2 setae, interior scuto­scutellar sclerites fused, bearing together 1 pair setae. Prehypopleural sclerite strongly chitinized and modified for articulation with coxa. Leg ( Fig. 1E ) strongly chitinized, 5­segmented, tarsungulus strongly curved, with single basal seta, paryonychial appendix prominent, fleshy; tibiae bearing 1 dorsal apical seta, 1 pair dorsal setae, 1 pair ventral sub­apical setae and 1 placoid sensillum; femur bearing 1 pair dorso­apical setae, 3 setae ventrally as shown, femora fused to trochanter; trochanter bearing 4 setae and 4 placoid sensilla near coxal articulation; coxa partially membranous with internal melanized sclerotization as shown ( Fig. 1E ) bearing 3 long setae and 4 minute setae near coxal articulation with pre­hypopleural scerite.

Abdomen. Abdominal segments I–VIII with a transverse median groove forming 2 plicae, and an identical arrangement of sclerites ( Fig. 1A, 1C ); each segment bearing 1 medial interior prescutal sclerite with 2 pairs setae, epipleural tubercle prominent bearing 4 long setae, posterior parascutal sclerite bearing 2 setae just posterior to annular spiracle, exterior scuto­scutellar sclerite bearing 2 setae, interior scuto­scutellar sclerites fused, bearing together 1 pair setae; ventrum bearing 4 small setae arranged transversely. Segment IX elongate, bearing 3 pairs dorsal setae and 4 pairs ventral setae. Segment X forming anal pseudopod bearing 3 pairs short setae ventrally and 4 placoid sensilla on each pleuron.

Material Examined. Maquine´, 15–28 II. 1998, reared, C. N. Duckett, 25 larvae; Porto Alegre, 5–15 III.1998, reared 7 larvae.

Pupa ( Figs. 3A–C ).

Color: pale orange.

Morphometrics: length: 4.3–5.3 mm; width 1.8–2.3 mm.

Head. Rounded, not visible in dorsal view, bearing 3 pairs of long setae, 1 pair subantennal, situated on frons near midline, 2 pairs on vertex, 1 pair ocular and 1 robust pair post­ocular near midline. Mouthparts well developed, distinct ( Fig. 3A ). Labrum elongate, apex gently rounded at corners. Mandibles sclerotized apically, with 3 minute teeth. Maxillary and labial palpi sub­globose. Antennal segments each bearing 2–3 papillae.

Thorax. Pronotum trapezoidal ( Fig. 3C ), 1.25× wide as long, bearing 8 pairs setae; anterior edge bearing 2 pairs setae grouped between pronotal corner and midline, lateral edge bearing 3 setae, 1 near each corner and 1 slightly anterior to midpoint; disk bearing 2 pairs near midline; posterior edge bearing 1 pair in lateral quarter of pronotal margin. Meso­ and metanota bearing 2 pairs setae. Legs bearing 1 pair short setae subapically on femora.

Abdomen. Abdominal terga I–VII bearing 3 pairs of long setae evenly spaced across dorsal surface ( Fig. 3C ), setae borne on small slightly melanized conical tubercles. Each segment bearing melanized annular spiracle and 1 pleural seta, originating from a prominent tubercle, ventro­posteriorly to each spiracle. Spiracle on segment VII reduced. Ventral surface glabrous. Segment VIII invisible dorsally, bearing 4 pairs setae perianally ( Fig. 3B ); 2 pairs posteriorly near midline and two pairs anterolaterally, 1 on each side of anal area. Urogomphi absent.

Material Examined. Maquine´, 20–28 III. 1998, reared, C.N.Duckett. 11 pupae .

Eggs: 0.8–1.0 mm in diameter, yellow, subconical, parallel­sided basally, smooth surface.

Material Examined. Maquine´, 11–25 II & 1–28 III. 1998, 10 clutches .

Biological Notes

Yingaresca holosericea feeds diurnally on Cordia monosperma both in the adult and larval stages. Eggs are usually laid on the surface of leaves in groups of 3–50, mean = 25, (n = 13). One gravid female maintained in captivity for more than two weeks laid 159 eggs in 7 clutches in the first 7 days of captivity. Observations of this female indicated that eggs were usually laid at night or in the early evening. Eggs hatch in 3 or 3.5 days; larvae exit by means of a small rounded hole and do not eat the remaining chorion. First instar larvae disperse to the axils of the host plant, next to the midrib or near folds of small, still expanding leaves or between new leaves, eating mesophyll between leaf hairs. The first instar lasts 4 days, the second, 4–6 days, and the final, 7–8 days including the prepupal period. Pupation is preceeded by a wandering phase where the larva seeks a rolled leaf, appressed leaves or soil. The larvae construct a pupal coccon of fine, irregular brown fibers formed by a secretion. These are used to glue the leaves together if leaves are used for the coccon. The pupal period lasts 4 days and the teneral adult may remain in the cocoon for an additional day.

Adults are often found between appressed leaves or inside rolled leaves. Females are often found on the top of leaves with their heads down, their abdominal apex raised and their antennae extended anteriorly in parallel. While collecting individuals in this posture using an aspirator, we perceived a faint sweetish scent, different from that perceived merely aspirating an adult Y. holosericea in a different posture. This posture and scent could be for pheromone dispersal similar to that of Silphidae (D. Sites, pers. comm.).

Yingaresca holosericea was parasitized by tachinid flies in the first day of larval life, or possibly tachinid eggs were laid on the surface of leaves fed to captive larvae and subsequently eaten. Ten percent of larvae (n = 3) collected in the field later died when their tachinid parasitoids pupated.

Figures

Fig. 1. Yingaresca holosericea mature larva. A) Lateral habitus; B) ventral view of abdominal apex; C) dorsal view of abdominal segment II; D) leg; E) dorsal view of prothorax.

Fig. 2. Yingaresca holosericea head mature larva. A) Head, dorsal view, clypeus, labrum and stemma not drawn; B) head, ventral view; C) labium and maxillae, ventral view; D) labrum; E) maxilla, dorsal view; F) mandible; G) antenna.

Fig. 3. Yingaresca holosericea pupa. A) Ventral view; B) abdominal apex, ventral view; C) dorsal view.