Hybosa acutangula Spaeth, 1913

Świętojańska, Jolanta & Linzmeier, Adelita M., 2024, Description of immature stages of Hybosa acutangula Spaeth, 1913 (Coleoptera, Chrysomelidae, Cassidinae), Zootaxa 5519 (3), pp. 395-422 : 397-417

publication ID

https://doi.org/ 10.11646/zootaxa.5519.3.4

publication LSID

lsid:zoobank.org:pub:8CCF9FA6-695D-4FC3-A7B7-51CD2D1C4CBC

DOI

https://doi.org/10.5281/zenodo.13916719

persistent identifier

https://treatment.plazi.org/id/A2525A2A-FFD6-FA77-FF58-41E7FCF0FEA4

treatment provided by

Plazi

scientific name

Hybosa acutangula Spaeth, 1913
status

 

Hybosa acutangula Spaeth, 1913 View in CoL

Egg

( Figs 2–4 View FIGURE 1–6 )

Measurements (n = 5 [mm]). Mean length of egg: 1.38; width: 0.89 ( Table 1 View TABLE 1 ). Flat, elongated, integument slightly granulated, light brown; covered by a transparent mass placing them together and overlapping. Egg mass covered by a dark faecal shield, mostly rounded, measuring 5.6 mm x 4.7 mm (mean, n = 3).

First instar larva

( Figs 11–43 View FIGURE 11 View FIGURE 12 View FIGURE 13 View FIGURES 14–22 View FIGURES 23 View FIGURES 24–29 View FIGURES 30–36 View FIGURES 37–43 )

Measurements (n = 7 [mm]): length of body: 0.85–1.30; width of body: 0.55–0.60; length of supra-anal processes: 0.75–0.87; width of head: 0.40–0.42 ( Table 1 View TABLE 1 ). Length of body was measured without head, from anterior border of pronotum to the base of supra-anal processes; width of body was measured across metathorax without lateral scoli.

Body dorso-ventrally flattened, elongate-oval, narrowed posteriorly, widest across meso- and metathorax ( Fig. 11 View FIGURE 11 ). Larvae preserved in alcohol light yellow with a brown head and two brown spots on the pronotum, light brown supra-anal processes and legs.

Lateral scoli of fourth pair reduced thus body is with 15 pairs of scoli and a pair of supra-anal processes; additional distinct tubercles (which look like very short lateral scoli) apically armed with single seta is placed between scoli of second and third pair ( Figs 11 View FIGURE 11 , 12 View FIGURE 12 , 26, 27 View FIGURES 24–29 ). Scoli of thorax, of posterior pair on meso- and metathorax, and of last pair on abdomen the longest, slightly longer than half width of body. Remaining lateral scoli shorter, more or less of the same length, their length is as half length of the longest scoli. All lateral scoli apically armed with long seta ( Figs 28, 29 View FIGURES 24–29 ), each apical seta is as long as length of scoli on which seta is located; scoli without lateral branches but with a few setae (usually 2–4) on sides ( Figs 24, 25 View FIGURES 24–29 ). Supra-anal processes as long as length of abdomen, bent dorsally, basally covered with asperities then with spines, apexes rounded without apical setae ( Figs 11 View FIGURE 11 , 34–36 View FIGURES 30–36 ).

Anal turret distinct and 2-segmented ( Figs 11–13 View FIGURE 11 View FIGURE 12 View FIGURE 13 ).

Nine pairs of spiracles (one on thorax and eight on abdomen), each distinctly elevated, and visible from dorsal view ( Figs 11 View FIGURE 11 , 12 View FIGURE 12 , 31, 33 View FIGURES 30–36 ).

Body distinctly granulated ( Fig. 11 View FIGURE 11 ). Minute setae at anterior border of tergites and sternites; tergites and sternites with setae. Setae of tergites short, setae of sternites very long in comparison to setae of tergites. Setae of head and legs of the same type as of body ( Figs 11–15 View FIGURE 11 View FIGURE 12 View FIGURE 13 View FIGURES 14–22 , 23 View FIGURES 23 , 37–40 View FIGURES 37–43 ).

Each side of pronotum with ten setae; single campaniform sensillum on each anterior side, close to body axis ( Fig. 12 View FIGURE 12 ). Anterior border of meso- and metanotum with a pair of minute setae placed medially and two minute setae on each side laterally. Meso- and metanotum also with two rows of setae running along width of tergite: first with two setae placed antero-medially, and second with ten setae placed posteriorly; three setae on each antero-lateral side. Anterior border of abdominal tergite I with a pair of minute setae placed medially and two minute setae on each side laterally. Abdominal tergites II–VIII with a pair of minute setae at anterior border medially and single minute seta on each side laterally. One minute seta and one long seta close to each abdominal spiracle. Abdominal tergite I also with two rows of long setae running along width: with six setae placed anteriorly and second with four setae placed postero-medially. Abdominal tergites II–VIII on each side with a pair of long setae placed on each antero-lateral side and with row of four long setae placed postero-medially.

Anterior border of pro-, meso- and metasternum with two minute setae ( Fig. 13 View FIGURE 13 ). Two minute setae at base of each leg. Two pairs of pointed setae in the middle of pro-, meso and metasternum. Anterior margin of all abdominal sternites with one pair of minute setae placed medially. Moreover, abdominal sternites I–IV with eight long, pointed setae placed medially and two setae on each postero-lateral side. Abdominal sternite V with six long, pointed setae placed medially and two setae on each postero-lateral. Abdominal sternites VI–VII with four long, pointed setae placed medially and two setae on each postero-lateral side. Abdominal sternite VIII with four setae in the middle of segment. Single seta at base of each abdominal lateral scoli.

Head well sclerotized, hypognathous, retracted into pronotum. Median suture complete, connected with frontoclypeal suture ( Figs 14, 15 View FIGURES 14–22 , 37–40 View FIGURES 37–43 ). Clypeus distinct, wider than long, with one pair of setae and one pair of campaniform sensilla ( Fig. 14 View FIGURES 14–22 ). Six distinct stemmata on each side of head ( Figs 38, 40 View FIGURES 37–43 ).

Head on each side with four small, vertical, pointed setae (V 1–4; Figs 14 View FIGURES 14–22 , 37, 41 View FIGURES 37–43 ), and five frontal rows of long setae: row Fa with three setae, Fb with five setae, Fc with three (sometimes four—doubled Fc2) setae, Fd with single seta, Fe with two setae ( Fig. 14 View FIGURES 14–22 ). Temporal surface of head with three setae ( Fig. 15 View FIGURES 14–22 ).

Antennae 2-segmented, set in membranous ring ( Figs 22 View FIGURES 14–22 , 38, 43 View FIGURES 37–43 ). Both antennomeres stout but first is wider than long, and the second longer than wide. First antennomere with four campaniform sensilla, second with small seta on side at base and group of six peg-like sensilla at apex: one prominent (sensory appendix) and five small.

Labrum wider than long, anterior margin shallowly emarginate ( Figs 16, 17 View FIGURES 14–22 ). Dorsal side of labrum with a medial row of four setae and two pairs of campaniform sensilla placed centrally. Anterior margin with 16 setae: eight short, thin placed medially (not visible from dorsal side) in shallow emargination, three stout, long, placed on each lateral side, and one slim, long placed dorsally between thin and stout setae. A pair of fine setae, four campaniform sensilla, and 16 small sensilla usually arranged in four groups (each with four sensilla) in the mid part of ventral surface (epipharyngeal area). Numerous small spines in the central and lateral parts of ventral side of labrum.

Mandibles heavily sclerotized, palmate, with four distinct, triangular, apical teeth in one row, and two setae and two campaniform sensilla at base dorsally ( Figs 18, 19 View FIGURES 14–22 ).

Maxillae and labium connate ( Figs 20, 21 View FIGURES 14–22 , 42 View FIGURES 37–43 ). Each stipes (st) with three pointed setae. Mala (mal) not distinctly bordered from palpifer (pp), broad, truncate at the apex, bearing: six pointed setae, single blunt seta, one peg like sensillum and one campaniform sensillum. Dorsally palpifer covered with spines ( Fig. 21 View FIGURES 14–22 ). Ventrally palpifer with two setae and two campaniform sensilla ( Fig. 20 View FIGURES 14–22 ). Maxillary palp 2-segmented: first segment (mpI) with 2 setae and one campaniform sensillum, second segment (mpII) with a group of sensilla at apex, and one campaniform sensillum and one seta below the apex. Labial palp (lp) one-segmented with a group of sensilla at the apex ( Fig. 42 View FIGURES 37–43 ) and single campaniform sensillum below the apex. Hypopharynx (hyp) covered with numerous spines, with four campaniform sensilla at base. Prementum (pre) with two setae and four campaniform sensilla. Postmentum (post) with six setae.

Legs elongate ( Figs 23 View FIGURES 23 , 30, 32 View FIGURES 30–36 ), 3-segmented, consisting of: coxa, femur, tibiotarsus and pretarsus. Internal side of coxa with setae arranged in three groups: first group with two short, pointed setae (placed at border between coxa and body); second with three pointed setae; third with three short pointed setae and one long seta. Two short, pointed setae on coxa externally. Femur with eleven long setae (two of them very long, 2–3 times longer than remaining setae on femur, placed ventrally) and a short seta placed dorsally close to the base. Moreover, base of femur with a group of five campaniform sensilla and very short-pointed seta internally, one campaniform sensillum ventrally, and two campaniform sensilla externally. Two long apically blunt setae on tibiotarsus dorsally. Pretarsus heavily sclerotized, in form of short and curved, single, and simple claw armed basally with a pointed seta. Claw surrounded by a group of six blunt, apically curved setae; pointed seta and two campaniform sensilla dorsally at base of claw.

Fifth instar (mature) larva

( Figs 7, 8 View FIGURE 7–10 , 44, 45 View FIGURES 44–47 , 48–64 View FIGURES 48–51 View FIGURES 52, 53 View FIGURES 54–62 View FIGURES 63, 64 )

Measurements in mm (n = 8): length of body: 7.40–10.50; width of body: 3.50–4.50; length of supra-anal processes (measured like in Fig. 8 View FIGURE 7–10 ): 2.00; width of head: 1.50–1.65 ( Table 1 View TABLE 1 ). Length of body was measured without head, from anterior border of pronotum to the base of supra-anal processes; width of body was measured across metanotum without lateral scoli.

Alive larva yellow whereas larvae preserved in alcohol straw-coloured (yellowish-white) with brown head, lateral scoli and spiracles; supra-anal processes brown ventrally and with four brown spots at base dorsally; coxae brown, femora brown at base and around distal part, tibiotarsi brown dorsally ( Figs 7, 8 View FIGURE 7–10 , 44, 45 View FIGURES 44–47 ). Body elongate-oval, slightly flattened dorso-ventrally, widest across meso- and metathorax, abdominal segments very slightly narrowed posteriorly ( Figs 44, 45 View FIGURES 44–47 ). Sixteen pairs of lateral scoli and a pair of supra-anal processes: four pairs of lateral scoli on prothorax, two pairs on meso- and metathorax, and a pair on each abdominal segment (I–VIII). No scoli at the level of the thoracic spiracles. First three thoracic lateral scoli placed close each other, scoli of first pair pointed in direction of head; scoli of third pair shorter than remaining thoracic scoli, pointed opposite to scoli of first pair. Scoli of anterior meso- and metathoracic pairs slightly shorter than of posterior pairs. Abdominal scoli similar in size with thoracic scoli. In general, all lateral scoli short (in relation to the body width), approximately as long as 1/4 of width of segment on which they are placed. Scoli without lateral branches, covered with setae (each placed in tiny tubercle) and apically armed with pointed seta ( Fig. 51 View FIGURES 48–51 ). Supra-anal processes short and stout, bent dorsally, covered with pointed setae in 2/3 basal length, without apical seta ( Figs 8 View FIGURE 7–10 , 44 View FIGURES 44–47 ).

Anal turret distinct and 2-segmented ( Fig. 45 View FIGURES 44–47 ).

Nine pairs of spiracles (one pair on thorax and eight on abdomen). Diameter of spiracles slightly decreasing posteriorly. Thoracic spiracles with the largest diameter and last abdominal spiracle with the smallest diameter visible from lateral side. Abdominal spiracles I–VII well visible from dorsal view ( Fig. 44 View FIGURES 44–47 ).

Body granulated (pronotum and sternites less granulated than the rest of tergites) with pointed setae on tergites and sternites ( Figs 48–50 View FIGURES 48–51 , 52, 53 View FIGURES 52, 53 ). Setae of sternites mostly longer than those on tergites. Most setae of tergites placed on tiny tubercles. Setae on pronotum distributed regularly on whole surface, setae along lateral side shorter than setae placed in the middle, along body axis ( Figs 48, 49 View FIGURES 48–51 ). Meso-, metanotum and abdominal tergites with two minute setae at anterior border medially and two rows of setae which running across segment ( Fig. 50 View FIGURES 48–51 ). Setae equally numerous on each tergite. Two minute setae at anterior border of pro-, meso- and metasternum. Medially pro-, meso- and metasternum with two groups of setae placed anteriorly (very close to each other) and two groups of three setae placed posteriorly ( Fig. 52 View FIGURES 52, 53 ). Each abdominal sternite with two minute setae at anterior border and with irregular row of pointed setae running across segment. Setae placed medially on abdominal sternite I–V longer and more numerous than setae placed laterally and on remainder abdominal sternites ( Fig. 53 View FIGURES 52, 53 ).

Head well sclerotized, hypognathous, retracted into pronotum. Median suture complete, connected with frontoclypeal suture. Clypeus distinct, wider than long, with a pair of setae and a pair of campaniform sensilla ( Fig. 54 View FIGURES 54–62 ). Six, distinct stemmata on each side of head.

Four, vertical, minute setae on each side of head (V 1–4); numerous, pointed setae on frontal side and 5– 6 pointed setae on each temporal side of head ( Figs 54, 55 View FIGURES 54–62 ).

Antennae 2-segmented, set in membranous ring ( Fig. 62 View FIGURES 54–62 ). First segment stout, wider than long, the second longer than wide. First segment with four campaniform sensilla, second with small seta on side at base and group of six peg-like sensilla on the apex: one prominent (sensory appendix) and five small.

Labrum wider than long, anterior margin distinctly emarginate ( Figs 56, 57 View FIGURES 54–62 ). Dorsal side of labrum with a medial row of four long setae and two pairs of campaniform sensilla placed centrally. Anterior margin with 14 setae placed ventrally and two dorsally. A pair of small setae, four campaniform sensilla, and four groups of 4–5 small sensilla placed in the mid part of ventral surface (epipharyngeal area). Numerous small spines on over most of the ventral side of the labrum.

Mandibles heavily sclerotized, palmate, with four triangular, apical teeth, and two setae and two campaniform sensilla at base dorsally ( Figs 58, 59 View FIGURES 54–62 ). Margins of mandibular teeth finely crenulate.

Maxillae and labium connate ( Fig. 60 View FIGURES 54–62 ). Each stipes (st) with three pointed setae. Mala (mal) not distinctly bordered from palpifer (pp). Six long pointed setae, single blunt seta, one peg like sensillum and one campaniform sensillum at the apex of broad, truncate mala. Dorsally palpifer covered with spines ( Fig. 61 View FIGURES 54–62 ). Ventrally palpifer with two long setae and two campaniform sensilla. Maxillary palp 2-segmented: first segment (mpI) with two setae and one campaniform sensillum, second segment (mpII) with a group of sensilla on apex, and with one campaniform sensillum and one pointed seta below the apex. Labial palp (lp) one-segmented with group of sensilla on the apex and campaniform sensillum below the apex. Hypopharynx (hyp) covered with numerous spines, with four campaniform sensilla at base. Prementum (pre) with two pointed setae and four campaniform sensilla. Postmentum (post) with about 12 pointed setae.

Legs stout, consisting of coxa, femur, tibiotarsus and pretarsus, all segments covered with pointed setae, more or less of the same length, distributed like on figures 63, 64. Additionally, four short pointed setae on coxa externally; group of five campaniform sensilla and short pointed seta at base of femur internally, one campaniform sensillum ventrally, and two campaniform sensilla externally. Pretarsus heavily sclerotized, short and curved, single and simple, armed basally with pointed seta. Pointed seta and two campaniform sensilla dorsally at base of pretarsus.

Pupa

( Figs 9, 10 View FIGURE 7–10 , 46, 47 View FIGURES 44–47 )

Measurements in mm (n = 6): length of body: 9.00–10.00; width of body: 3.10–4.80; length of pronotum: 2.10–2.80; width of pronotum: 5.20–5.60. Length of body was measured from anterior border of pronotum to the posterior border of abdominal segment VIII (at base of supra-anal processes); width of body was measured across third abdominal segment, without lateral scoli.

Body rounded-oval to elongated, surface distinctly texturized, living pupae yellow ( Figs 9, 10 View FIGURE 7–10 ), preserved in alcohol—straw-coloured; in both alive and alcohol-preserved pupae, tips of lateral processes of abdominal segments I–V and spiracles of abdominal tergites I–V black ( Figs 46, 47 View FIGURES 44–47 ). Body covered with numerous, regularly distributed minute setae, each placed on tiny tubercle (tubercles smaller than those on the lateral scoli of the mature larva). Numerous spinules in posterior part (along posterior margin) of abdominal tergites; number of spinules on successive segments gradually increases posteriorly.

Vertex of head with two conic projections (in ventral view) ( Fig. 47 View FIGURES 44–47 ). Anterior margin of pronotum rounded, with central area straighter, with a small notch medially (not so clearly visible in all specimens); presence of two pairs of very short (hardly visible), conical, marginal processes with tiny tubercles bearing single seta. Posterior angles of pronotum projected backwards, slightly curved inward, covered with minute setae, each placed on tiny tubercle.

Pro-, meso- and metanotum without lateral scoli. Abdominal segments I–V with a pair of conical, pointed forward lateral scoli which gradually shortened posterad; scoli covered with tiny tubercles bearing single seta; a group 3–6 setae at the apex of each scolus. Lateral scoli of segments VI–VIII short, thin, in form of simple processes, pointing backwards. Lateral scoli of abdominal segment VI ended with single seta; scoli of segments VII and VIII without setae. Segment IX with a pair of short processes (shorter but stouter than scoli of abdominal segments VI–VIII) covered with numerous spinules which look like spinules on tergites. Diameter of spiracle of each abdominal pair decrease posteriorly. Spiracles of abdominal tergites I–V slightly elevated from body level, spiracles of abdominal segments VI–VIII visible only on microscopic slides. The cast skin of the last instar is retained by the pupa ( Figs 46, 47 View FIGURES 44–47 ).

Biological notes

Adults, larvae and egg masses were found on the host plant ( Figs 1–6 View FIGURE 1–6 ). The eggs are laid in groups (egg mass), in horizontal, overlapping layers with among 12 to 35 eggs, covered by a dark, rounded faecal shield ( Figs 2–4 View FIGURE 1–6 ). The egg mass is always laid in the fork of twigs where the branches leave the main trunk ( Fig. 2 View FIGURE 1–6 ). Once hatched, the larvae group at the leaf margin where they are feeding (mainly first and second instar) and in older instars the groups become less numerous; groups of larvae forming circles were also observed ( Fig. 5 View FIGURE 1–6 ), where larval heads were turned to the centre of the group (cycloalexy). After each molt the exuvia remains attached to the supra-anal process together with moist faeces, forming a triangular mass that can be moved up and down by the larva when disturbed. Also, when disturbed, larvae tend to disperse ( Fig. 6 View FIGURE 1–6 ).

Most of the egg masses sampled (n=13) were parasitized by a Chalcidoidea microhymenoptera or developed fungi and no larva hatched from them. The egg parasitoid should belong to Emersonella Girault, 1916 ( Eulophidae ), known to parasitise Hybosa and recorded as egg parasitoid of Neotropical Cassidinae ( Cuignet et al. 2007) . From the two remaining egg masses 38 larvae hatched (in one group 14 and in the other 24 larvae) which had a high mortality under laboratory conditions (28 oC; ca. 75% RH). The developmental time under laboratory conditions from first instar larva to adult was estimated at 21 days.

TABLE 1. Measurements of egg, egg mass, first and fifth instar larva and pupa of Hybosa acutangula (Coleoptera, Chrysomelidae, Cassidinae).

egg length [mm] width [mm]    
1. 1.40 0.90    
2. 1.40 0.80    
3. 1.30 0.90    
4. 1.50 0.95    
5. 1.30 0.90    
egg mass length [mm] width [mm]    
1. 6.00 4.50    
2. 4.80 4.50    
3. 6.00 5.30    
first instar larva length of body [mm] width of body across metathorax [mm] length of supra-anal processes [mm] width of head [mm]
1. 0.85 0.55 0.75 0.40
2. 0.95 0.56 0.80 0.40
3. 1.10 0.55 0.80 0.40
4. 1.25 0.57 0.78 0.42
5. 1.25 0.55 0.80 0.42
6. 1.30 0.60 0.87 0.42
7. 1.25 0.57 0.82  
fifth instar larva length of body [mm] width of body across metathorax [mm] length of supra-anal processes [mm] width of head [mm]
1. 10.50 4.40 2,00 1.52
2. 7.50 4.00 2,00 1.55
3. 7.40 3.50 2,00 1.65
4. 10.00 4.10 2,00 1.50
5. 8.00 4.00 2,00 1.60
6. 8.50 3.80 2,00 1.65
7. 9.00 4.50 2,00 1.50
8. 9.00 4.10 2,00 1.60
pupa length of body [mm] width of body across 3rd abdominal segment [mm] length of pronotum [mm] width of pronotum [mm]
1. 9.00 3.70 2.10 5.20
2. 10.00 3.60 2.60 5.60
3. 9.00 3.70 2.50 5.40
4. 9.90 4.80 2.80 5.50
5. 9.90 4.60 2.60 5.50
6. 9.00 3.10 2.30 5.10

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Coleoptera

Family

Chrysomelidae

Genus

Hybosa

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