Sibinia attalica Gyllenhal, 1835

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 : 155-159

Sibinia attalica Gyllenhal, 1835

Caldara, 1985: 58.

Material examined. 11 larvae from seeds of Silene gallica L. collected 27.v.1979 at Santa Lucia di Siniscola (Nuoro province, Sardinia), leg. R. Caldara, and 31 (13 ♂♂, 18 ♀♀) 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. All thoracic and abdominal segments white to whitish

yellow.

HEAD CAPSULE AND MOUTH PARTS. Head width: 0.75–0.88 mm (see Table. 1). Endocarinal line present, distinctly reaching middle of frons. Des1 very short, located almost in central parts of epicarnium; des2 absent; des3 long, located along frontal suture; des4 absent; des5 long, located anterolaterally ( Fig. 1 ). Fs1 and fs2 absent; fs3 minute, located medially; fs4 long, located anteromedially (along epistoma); fs5 long, located anterolaterally (along epistoma) ( Fig. 1 ). Les almost as long as des3; both ves short. Postepicranial area without pes and with 5 sensilla. Antennal segment membranous, bearing conical sensorium and 2 very short, conical, sensilla ( Fig. 4 ).

Clypeus ( Fig. 5 ) 2.5 times as wide as long; without setae, and 1 sensillum, all located posterolaterally; anterior margin slightly rounded inside. Labrum ( Fig. 5 ) approximately 2 times as wide as long; lms1 distinctly shorter than lms2, and as long as lms3; anterior margin slightly sinuate. Epipharynx ( Fig. 6 ) with 2 finger-like als, different in length; with 3 short ams, ams1 as long as ams2; with 2 relatively short and finger-like mes (see comments about ams and mes in Material and Methods); labral rods short, kidney-shaped, strongly converging posteriorly. Mandibles ( Fig. 3 ) with 1 very short mds. Maxilla ( Fig. 2 ): stipes with 1 long stps, and with 2 long pfs, pfs1 2 times as long as pfs2; 1 very short mbs; mala with 4 slightly curved dms, different in length; with 3 moderately short vms, almost of equal length. Maxillary palpi: length ratio of basal and distal palpomeres 1:1.5; basal palpomera with 1 short mxps; distal palpomera with group of 3–4 conical, cuticular apical processes. Prementum ( Fig. 2 ) almost rounded, with 1 prms; margin of ligula slightly curved inside; ligula with 2 very short to short ligs; premental sclerite clearly visible. Postmentum ( Fig. 2 ) with 2 pms, pms1 absent, long pms2, 2 times as long as pms3.

THORAX AND ABDOMEN. Body length 4.30–5.30 mm (see Table. 1), elongate ( Fig. 7 ). Abdominal segments I– V almost equal in length, slightly larger than abdominal segment VI and VII ( Fig. 7 ). Spiracles on abdomen in median parts of segments (abdominal seg. I–VIII).

Chaetotaxy of body rather reduced. Setae moderately long to very short and light yellow. Thorax. Prothorax ( Fig. 8 ) with 7 prn, 6 macro- and 1 microsetae; 2 moderately long ps of same length; 1 short eus. Meso- and metathorax ( Fig. 8 ) with 1 long prs; 2 pds, different in length; alar area with 1 moderately long as; 1 moderately long ss; 1 moderately long eps; 2 moderately short ps, similar in length; and 1 short eus. Each pedal area of thoracic segments well-separated and with 2–4 moderately long pda. Abdomen. Abdominal segments I–VII ( Figs. 9, 10 ) with 1 long prs; 3 pds of different length, pds1 and pds3 very short, pds2 very long; 2 ss of different length, ss1 very short to minute, ss2 long; 2 eps moderately long, in equal length; 2 ps of different length, ps1 very short and ps2 long; 1 long lsts; and 2 very short eus. Abdominal segment VIII ( Fig. 10 ) with 1 short prs; 3 pds of different length, pds1 and pds3 minute, pds2 short; 1 minute ss; 2 short eps in equal length; 2 short ps of different length; 1 short lsts; and 2 very short eus. Abdominal segment IX ( Fig. 10 ) with 1 short ds; 2 short ps of different length; and 2 short sts in equal length. Anal lobes on abdominal segment X ( Fig. 10 ) without setae.

Description of pupa. COLORATION. Body yellow.

MORPHOLOGY ( Figs. 11–15 ). Body length 2.75–4.35 mm; widest part 1.55–2.20 mm (see Table. 2 ). Body rather elongated and slender. Rostrum long, approximately 6 times as long as wide, reaching mesocoxae. Pronotum 2.2 times as wide as long.

CHAETOTAXY ( Figs. 11–15 ). Setae distinct, short, unequal in length, light brown or brown, almost as thornlike. Vs and os slightly longer than other setae of head and rostrum ( Fig. 12 ). Ds slightly shorter than other setae on pronotum ( Fig. 14 ). Setae on abdominal segments I–VIII placed posteromedially and posterolaterally; all abdominal setae located on thorn-like protuberances, short, curved. Pseudocerci short, conical.

Biological observations. After feeding on seeds, mature larvae left the capsule and entered the soil. Pupation was observed 10 days after the larvae entered the soil. Adults were found in the cells 10 days later.

Remarks. This is a common species with a wide circum-Mediterranean distribution. It was reported to live on several species belonging to the genus Silene ( S. arenarioides Desf. , S. conica L., S. gallica L., S. maritima With. , and S. mellifera Boiss. & Reut. : Hoffmann 1955; Scherf 1964; Caldara 1985), which produce large seeds. Before the revision of the genus by Caldara (1985), this species was confused with S. femoralis , and therefore, much of the data on the host plants are doubtful.

Figures

FIGURES 1 – 6. Sibinia attalica mature larva head, antenna and mouth parts: 1 — dorsal view (des — dorsal epicranial s., fs — frontal epicranial s., les — lateral epicranial s., ves — ventro epicranial s., st—stemmata, at—antenna); 2 — 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.); 3 — right mandible (mds — mandible dorsal s.); 4 — antenna; 5 — labrum and clypeus (lms — labral s.); 6 — epipharynx (ams — anteromedial s., als — anterolateral s., mes — median s., lr—labral rods).

FIGURES 7 – 10. Sibinia attalica mature larva habitus: 7 — lateral view, 8 — lateral view of thoracic segments, 9 — lateral view of abdominal segment I, 10 — 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 11 – 15. Sibinia attalica pupa habitus: 11 — ventral view; 12 — detail of head; 13 — dorsal view; 14 — detail of pronotum; 15 — 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).