Tychius (s. str.) caldarai Dieckmann, 1986

Skuhrovec, Jiří, Gosik, Rafał & Caldara, Roberto, 2014, Immatures of Palaearctic species of the weevil genus Tychius (Coleoptera, Curculionidae): new descriptions and new bionomic data with an evaluation of their value in a phylogenetic reconstruction of the genus, Zootaxa 3839 (1), pp. 1-83 : 16

Tychius (s. str.) caldarai Dieckmann, 1986

Caldara, 1990: 168.

Material examined. 9 larvae obtained from pods of Dorycnium pentaphyllum Scop. collected 15.vi.1992 at Parodi Ligure , Alessandria province, Piemonte (northern Italy), leg. R. Caldara, and 7 pupae obtained from larvae collected contemporaneously together with the others, all determined by association with reared adults.

Differential diagnosis. See Tables 2 and 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: 0.36–0.40 mm (see Table. 1 ). Endocarinal line present, exceeding middle of frons. Des 1, des 2, des 3 and des 4 located very near frontal suture; des 5 located laterally; des 2 and des 4 4 times shorter than others (des 1, des 3, des 5) ( Fig. 99 ). Fs 1–3 absent; fs 4 located anteromedially (along epistoma); fs 5 located anterolaterally (along epistoma) ( Fig. 99 ). Les almost equal in length as des 3. Ves very short. Postepicranial area with 1 minute pes. Antennal segment membranous, bearing conical sensorium and 2 very short, conical, sensilla ( Fig. 102 ).

Labrum ( Fig. 103 ) approximately 3 times as wide as long; lms 1 slightly longer than lms 3, lms 2 almost of same length as lms 1; anterior margin slightly curved inside. Clypeus ( Fig. 103 ) 3.5 times as wide as long; with 2 pairs of very short cls of same length, and 1 sensillum, all located posterolaterally; anterior margin slightly rounded. Epipharynx ( Fig. 104 ) with 2 pairs of als, almost of equal length; with 2 pairs of short ams, ams 1 distinctly shorter than ams 2; with 2 long finger-like and 1 short mes; labral rods short, kidney-shaped, strongly converging posteriorly. Mandibles ( Fig. 101 ) with 2 short mds. Maxilla ( Fig. 100 ): stipes with 1 stps, and 2 pfs of equal length; mala with 4 straight dms, different in length; with 3 vms, short and almost of equal length. Maxillary palpi: length ratio of basal and distal palpomeres 1:1.3; basal palpomera with 1 short mpxs; distal palpomera with group of 3–4 conical, cuticular apical processes. Prementum ( Fig. 100 ) almost rounded, with 1 prms; margin of ligula slightly curved inside; ligula with 3 lig; premental sclerite distinct. Postmentum ( Fig. 100 ) with 3 pairs of pms, different in length.

THORAX AND ABDOMEN. Body length 1.9–2.3 mm (see Table. 1 ), elongate. Spiracles on abdomen in anteromedian parts of segments (abdominal seg. I–VIII).

Chaetotaxy of body reduced. Setae moderately short or very short and light yellow. Thorax. Prothorax ( Fig. 106 ) with 8 prn, 6 macro- and 2 microsetae; 2 moderately long ps of same length; 1 eus. Meso- and metathorax ( Fig. 106 ) with 1 prs; 3 pds, different in length; alar area with 1 very short as; 1 very short ss; 1 eps; 1 ps; and 1 short eus. Each pedal area of thoracic segments well-separated and with 3 pda, different in length (long, moderately long, short). Abdomen. Abdominal segments I–VII ( Fig. 107 ) with 1 prs; 1 pds; 1 ss; 1 eps; 1 ps; and 2 short eus. Abdominal segment VIII ( Fig. 108 ) with 1 pds; 1 eps; 1 ps; and 2 short eus. Abdominal segment IX ( Fig. 108 ) with 1 ds; 1 ps; and 1 sts. Anal lobes on abdominal segment X ( Fig. 108 ) with 1 very short, feebly visible seta.

Description of pupa. COLORATION. Body whitish yellow.

MORPHOLOGY ( Figs. 109–111 ). Body length 2.6–2.8 mm; widest part 0.9–1.1 mm (see Table. 1 ). Body elongate. Rostrum long, approximately 6 times as long as wide, reaching mesocoxae. Pronotum 1.5 times as wide as long.

CHAETOTAXY ( Figs. 109–111 ). Setae distinct, moderately long, unequal in length, light brown; on pronotum and head placed on small protuberances. Head capsule including 1 vs, 1 os, and 1 pas. Rostrum with 1 rs located medially. Vs and os as long as setae on pronotum, distinctly longer than pas and rs. Pronotum with 2 as, 2 ls, 2 ds, and 1 pls; ds as long as other setae on pronotum. Dorsal parts of meso- and metathorax with 1 seta. Each apex of femora with 1 fes. Setae on abdominal segments I–VIII placed medially and laterally; all abdominal setae located on small, conical protuberances. Pseudocerci slender, slightly curved inside.

Biological observations. Pupae were found in their cells after 8 days from the introduction of larvae into the soil. The pupal stage lasted 10 days. Adults were observed first in pupal cells after another 12 days. No adult left its cell during the following 30 days, and then they were removed artificially.

Remarks. This species is monophagous on Dorycnium pentaphyllum and known from south-western Europe. It is very similar to and vicariant with T. cinnamomeus Kiesenwetter, 1852 from southern Spain, southern France and northwestern Italy living on the same plant.

Figures

FIGURES 99–104. Tychius caldarai mature larva head, antenna and mouth parts: 99—dorsal view (des—dorsal epicranial s., fs—frontal epicranial s., les—lateral epicranial s., ves—ventral epicranial s., pes—posterior epicranial s., st—stemmata, at—antenna); 100—right maxilla, dorsal view (dms—dorsal malar s., vms—ventral malar s., mpxs—maxillary palps s., pfs—palpiferal s., stps—stipital s.), prementum and postmentum, ventral view (prms—premental s., pms—postmental s., ligs—ligular s.); 101—right mandible (mds—mandible dorsal s.); 102—antenna; 103—labrum and clypeus (cls—clypeal s., lms—labral s.); 104—epipharynx (ams—anteromedial s., als—anteriolateral s., mes—median s., lr—labral rods).

FIGURES 105–108. Tychius caldarai mature larva habitus: 105—lateral view, 106—lateral view of thoracic segments, 107—lateral view of abdominal segment I., 108—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., eus—eusternal s., ds—dorsal s., sts—sternal s.).

FIGURES 109–111. Tychius caldarai pupa habitus: 109—ventral view, 110—dorsal view, 111—lateral view (vs—vertical s., os—orbital s., pas—postantennal s., rs—rostral s., as—apical s., ls—lateral s., ds—discal s., pls—posterolateral s., fes—femoral s., pc—pseudocerci).