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 Author Skuhrovec, Jiří Author Gosik, Rafał Author Caldara, Roberto Author Košťál, Michael text Zootaxa 2015 2 151 187 journal article http://dx.doi.org/10.11646/zootaxa.3955.2.1 ef3ddc5d-a90b-49df-a2b8-01282c0509fe 1175-5326 239116 2C428174-7C02-4F0C-BB34-E1BC81F58CB1 Sibinia sicana Ragusa, 1908 Caldara, 1985 : 85 . Material examined . 40 larvae from seeds of Gypsophila arrostii Guss. collected 2 .vii. 1989 at Aidone (Enna province, Sicily), leg. R. Caldara, and 6 ( 4 ♂♂, 2 ♀♀) 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: 0.48–0.53 mm (see Table. 1 ). Endocarinal line present, distinctly reaching middle of frons. Des 1 very short, located close to frontal suture; des 2 absent; des 3 very long, located along frontal suture; des 4 absent; des 5 moderately long, located anterolaterally, des 3 2.5 times as long as des 5 ( Fig. 61 ). Fs 1 and fs 2 absent; fs 3 minute, located medially; fs 4 moderately long, located anteromedially (along epistoma); fs 5 very long, located anterolaterally (along epistoma), fs 5 2.5 times as long as fs 4 ( Fig. 61 ). Les almost as long as des 3 ; both ves short. Postepicranial area without pes and with 5 sensilla. Antennal segment membranous, bearing conical sensorium and 2 very short, conical, sensilla ( Fig. 64 ). Clypeus ( Fig. 65 ) 3 times as wide as long; with 1 very short cls , and 1 sensillum, all located posterolaterally; anterior margin slightly rounded inside. Labrum ( Fig. 65 ) approximately 2.1 times as wide as long; lms 1 distinctly shorter than lms 2 , and as long as lms 3 ; anterior margin slightly sinuate. Epipharynx ( Fig. 66 ) with 2 long, finger-like als , different in length; with 3 short ams , in equal length; with 2 relatively short mes (see comments about ams and mes in Material and Methods); labral rods short, kidney-shaped, strongly converging posteriorly. Mandibles ( Fig. 63 ) with 1 very short mds . Maxilla ( Fig. 62 ): stipes with 1 very long stps , and with 2 very long pfs , of similar length; 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 : 1.7 ; basal palpomera with 1 short mxps ; distal palpomera with group of 3–4 conical, cuticular apical processes. Prementum ( Fig. 62 ) almost rounded, with 1 long prms ; margin of ligula slightly curved inside; ligula with 1 ligs ; premental sclerite clearly visible. Postmentum ( Fig. 62 ) with 2 pms , pms 1 absent, moderately long pms 2 , 2 times as long as pms 3 . THORAX AND ABDOMEN. Body length 2.60 –3.00 mm (see Table. 1 ), elongate ( Fig. 67 ). Abdominal segments I– V almost equal in length, slightly larger than abdominal segment VI and VII ( Fig. 67 ). Spiracles on abdomen in median parts of segments (abdominal seg. I–VIII). FIGURES 61–66. Sibinia sicana mature larva head, antenna and mouth parts: 61—dorsal view ( des —dorsal epicranial s., fs — frontal epicranial s., les —lateral epicranial s., ves —ventro epicranial s., st—stemmata, at—antenna); 62—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.); 63—right mandible ( mds —mandible dorsal s.); 64—antenna; 65—labrum and clypeus ( cls —clypeal s., lms —labral s.); 66—epipharynx ( ams —anteromedial s., als —anterolateral s., mes —median s., lr—labral rods). FIGURES 67–70. Sibinia sicana mature larva habitus: 67—lateral view, 68—lateral view of thoracic segments, 69—lateral view of abdominal segment I, 70—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., Th1–3—number of thoracic segments, Ab1–10—number of abdominal seg.). FIGURES 71–75. Sibinia sicana pupa habitus: 71—ventral view; 72—detail of head; 73—dorsal view; 74—detail of pronotum; 75—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). Chaetotaxy of body rather reduced. Setae long to very short and light yellow. Thorax. Prothorax ( Fig. 68 ) with 9 prn , 6 macro- and 3 microsetae; 2 long ps of same length; 1 short eus . Meso- and metathorax ( Fig. 68 ) with 1 moderately long prs ; 2 long pds , similar in length; alar area with 1 long as ; 1 long ss ; 1 long eps ; 2 moderately long ps , similar in length; and 1 short eus . Each pedal area of thoracic segments well-separated and with 2–3 moderately long to long pda . Abdomen. Abdominal segments I–VII ( Figs. 69, 70 ) with 1 long prs ; 3 long pds of similar length, pds 1 and pds 3 slightly shorter than pds 2 ; 2 ss of different length, ss 1 very short to minute, ss 2 moderately long; 2 long eps in equal length; 1 moderately long ps ; 1 moderately long lsts ; and 2 short eus . Abdominal segment VIII ( Fig. 70 ) with 1 short prs ; 3 relatively short pds of similar length, pds 1 and pds 3 slightly shorter than pds 2 ; 1 minute ss ; 2 moderately long eps in equal length; 1 moderately long ps ; 1 moderately long lsts ; and 2 short eus . Abdominal segment IX ( Fig. 70 ) with 1 moderately long ds ; 2 moderately long ps of similar length; and 2 moderately long sts in equal length. Anal lobes on abdominal segment X ( Fig. 70 ) without setae. Description of pupa. COLORATION. Body white. MORPHOLOGY ( Figs. 71–75 ). Body length 1.67–2.34 mm ; widest part 1.16–1.40 mm (see Table. 2 ). Body moderately elongated. Rostrum medium long, approximately 3.1 times as long as wide, reaching almost to mesocoxae. Pronotum 1.37 times as wide as long. CHAETOTAXY ( Figs. 71–75 ). Setae distinct, long, all equal in length (except on abdominal seg. IX), light, hairlike. Setae on abdominal segments I–VIII placed posteromedially and posterolaterally; all abdominal setae located on small, conical protuberances. Pseudocerci elongated, slightly curved to inside. Biological observations. The host plant, Gypsophila arrostii Guss. , was previously unknown. It is an endemic species of southern Italy and Sicily. The larvae fed on seeds and, as with other species, left the capsule when mature. Pupation was observed 8 days after the larvae entered the soil. Adults were found in the cells 10 days later. Remarks. With its host plant, this species is only found in southern Italy (Basilicata and Calabria) and Sicily and was considered very rare. However, adults were collected in large numbers on its flowering host plant in a season when typically in Sicily almost the whole herbs are dry and the collection of weevils by netting was unlikely to be conducted. Additionally, S . unicolor Fåhraeus, 1843 , which is a closely related species to S . sicana and is widely distributed in the central and Eastern Palaearctic, lives on Gypsophila ( G . paniculata L., G . papillosa Porta , and G . repens L.: Caldara 1985 ; Dieckmann 1988 ).