Sibinia sodalis Germar, 1824

Skuhrovec, Jiří, Gosik, Rafał, Caldara, Roberto & Košťál, Michael, 2015, Immatures of Palaearctic species of the weevil genus Sibinia (Coleoptera, Curculionidae): new descriptions and new bionomic data with suggestions on their potential value in a phylogenetic reconstruction of the genus, Zootaxa 2, pp. 151-187 : 176-180

Sibinia sodalis Germar, 1824

Caldara, 1979: 72.

Material examined. ca 200 larvae from seeds of Armeria vulgaris Willd. collected 5.viii. 2014 in southern Slovakia (Borská nížina, Malacky env. 150 m a. s. l., N 48°24.7´, E 17°04.0´), leg. J. Skuhrovec, M. Košťál & Z. Košťálová, and 76 (47 ♂♂, 29 ♀♀) pupae obtained from larvae collected similarly to the others, all determined by association with reared adults.

Differential diagnosis. See Key to the immatures of the Palaearctic species of the genus Sibinia and Table. 3 .

Description of mature larva. COLORATION. Head brown to dark yellow. All thoracic and abdominal segments light yellow.

HEAD CAPSULE AND MOUTH PARTS. Head width: 0.38–0.50 mm (see Table. 1). Endocarinal line present, very short, reaching almost to one-third of frons. Des1 absent; des2 minute, located almost in central parts of epicarnium; des3 long, located along frontal suture; des4 absent; des5 long, located anterolaterally ( Fig. 76 ). Fs1 and fs2 absent; fs3 minute, located medially; fs4 long, located anteromedially (along epistoma); fs5 very long, located anterolaterally (along epistoma), fs5 1.5 times as long as fs4 ( Fig. 76 ). Les almost as long as des3; one very short ves. Postepicranial area with 4 pes. Antennal segment membranous, bearing conical sensorium and 2 very short, conical, sensilla ( Fig. 79 ).

Clypeus ( Fig. 80 ) 2.5–3 times as wide as long; with 2 very short cls, and 1 sensillum, all located posterolaterally; anterior margin slightly rounded inside. Labrum ( Fig. 80 ) approximately 3–3.5 times as wide as long; lms1 distinctly shorter than lms2, and 2 times as long as lms3; anterior margin slightly sinuate. Epipharynx ( Fig. 81 ) with 2 short, finger-like als, similar in length; with 3 short ams, similar in length; with 2 very short and finger-like mes (see comments about ams and mes in Material and Methods); labral rods elongate, kidney-shaped, strongly converging posteriorly. Mandibles ( Fig. 78 ) without seta. Maxilla ( Fig. 77 ): stipes with 1 long stps, and with 2 long pfs, almost of equal length; 1 very short mbs; mala with 4 long, slightly curved dms, different in length; with 3 short vms, almost of equal length. Maxillary palpi: length ratio of basal and distal palpomeres 1:1.6; basal palpomera with 1 very short mxps; distal palpomera with group of 3–4 conical, cuticular apical processes. Prementum ( Fig. 77 ) almost rounded, with 1 relatively short prms; margin of ligula slightly curved inside; ligula with 3 very short to minute ligs; premental sclerite clearly visible. Postmentum ( Fig. 77 ) with 2 pms, pms1 absent; pms2 long, 3 times as long as pms3.

THORAX AND ABDOMEN. Body length 2.00– 3.30 mm (see Table. 1), elongate ( Fig. 82 ). Abdominal segments I– V almost equal in length, slightly larger than abdominal segment VI and VII ( Fig. 82 ). Spiracles on abdomen in median parts of segments (abdominal seg. I–VIII).

Chaetotaxy of body rather reduced. Setae long to very short and light yellow. Thorax. Prothorax ( Fig. 83 ) with 8 prn, 6 macro- and 2 microsetae; 2 moderately long ps of same length; 1 moderately long eus. Meso- and metathorax ( Fig. 83 ) with 1 short prs; 2 pds, pds1 minute to very short, pds2 long; alar area with very short 1 as; 1 moderately long ss; 1 moderately long eps; 1 moderately long ps; and 1 moderately long eus. Each pedal area of thoracic segments well-separated and with 2 long pda. Abdomen. Abdominal segments I–VII ( Figs. 84, 85 ) with 1 short prs; 3 pds of different length, pds1 and pds3 short to very short, pds2 long; 2 ss of different length, ss1 minute, ss2 very short; 2 eps of different length, eps1 very short and eps2 long; 2 ps of different length, ps1 short and ps2 moderately long; 1 moderately long lsts; and 2 short eus. Abdominal segment VIII ( Fig. 85 ) with 1 short prs; 3 pds of different length, pds1 and pds3 short to very short, pds2 moderately long; 1 minute ss; 2 eps of different length, eps1 very short and eps2 long; 2 ps of different length, ps1 very short to minute and ps2 moderately long; 1 moderately long lsts; and 2 short eus. Abdominal segment IX ( Fig. 85 ) with 1 short ds; 2 ps of different length, ps1 short to very short and ps2 moderately long; and 2 sts of different length, sts1 short to very short and sts2 moderately long. Anal lobes on abdominal segment X ( Fig. 85 ) without setae.

Description of pupa. COLORATION. Body yellow.

MORPHOLOGY ( Figs. 86–90 ). Body length 2.25–3.00 mm; widest part 0.95–1.15 mm (see Table. 2 ). Body rather elongated. Rostrum long, approximately 5 times as long as wide, reaching mesocoxae. Pronotum 1.3 times as wide as long.

CHAETOTAXY ( Figs. 86–90 ). Setae distinct, short, unequal in length, light brown; on pronotum and head placed on small protuberances. Setae on head different in length, sos 2 times shorter than os; rs very short almost invisible ( Fig. 87 ). Pronotal setae slightly longer than those on head, rostrum, and abdominal segments; ds2 slightly shorter than other setae on pronotum ( Fig. 89 ). Setae on abdominal segments I–VIII very short, placed posteromedially and posterolaterally. Pseudocerci elongated, slightly curved inside.

Biological observations. The larvae fed on seeds, and mature larvae left the flower head and entered the soil to pupate. Pupation was observed 9–10 days after the larvae entered the soil. Adults were found in the cells 8–9 days later.

Remarks. This species is found typically on Armeria vulgaris Willd. , but larvae and adults were also collected on A. plantaginea Willd. in France ( Hoffmann 1955) and on A. allioides Boiss. in Algeria ( Peyerimhoff 1911). The larva and the pupa were described synthetically by Scherf (1964), who reported only on length and coloration of the body, with comments on chaetotaxy of the head, unfortunately with some inaccuracies (see Table. 3 ).

Figures

FIGURES 76 – 81. Sibinia sodalis mature larva head, antenna and mouth parts: 76 — dorsal view (des — dorsal epicranial s., fs — frontal epicranial s., les — lateral epicranial s., pes — posterior epicranial s., ves — ventro epicranial s., st—stemmata, atantenna); 77 — right maxilla, dorsal view (dms — dorsal malar s., vms — ventral malar s., mpxs — maxillary palps s., mbs — basioventral s., pfs — palpiferal s., stps — stipital s.), prementum and postmentum, ventral view (prms — premental s., pms — postmental s., ligs — ligular s.); 78 — right mandible; 79 — antenna; 80 — labrum and clypeus (cls — clypeal s., lms — labral s.); 81 — epipharynx (ams — anteromedial s., als — anterolateral s., mes — median s., lr—labral rods).

FIGURES 82 – 85. Sibinia sodalis mature larva habitus: 82 — lateral view, 83 — lateral view of thoracic segments, 84 — lateral view of abdominal segment I, 85 — lateral view of abdominal segments VII—X (prns — pronotal s., prs — prodorsal s., pds — postdorsal s., as — alar s., ss — spiracular s., eps — epipleural s., ps — pleural s., pda — pedal s., lsts — laterosternal s., eus — eusternal s., ds — dorsal s., sts — sternal s., Th 1 – 3 — number of thoracic segments, Ab 1 – 10 — number of abdominal seg.).

FIGURES 86 – 90. Sibinia sodalis pupa habitus: 86 — ventral view; 87 — detail of head; 88 — dorsal view; 89 — detail of pronotum; 90 — lateral view; (HW—head width; BW—body width; BL—body length; setae; as — apical s., d — dorsal s., ds — discal s., l — lateral s. on abdomen, ls — lateral s. on pronotum, os — orbital s., pas — postantennal s., pls — posterolateral s., sos — superorbital s., vs — vertical s.; pc—pseudocerci).