Tychius (s. str.) capucinus Boheman, 1843

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 : 14-15

Tychius (s. str.) capucinus Boheman, 1843

Caldara 1990: 164.

Material examined. 40 larvae from pods of Lotus ornithopodioides L. collected 26.v.1979 on sand dunes of the beach of Santa Lucia near Siniscola , Sassari province, Sardinia ( Italy), leg. R. Caldara, and 66 pupae obtained from larvae collected similarly to the others, all determined by association with reared adults.

Differential diagnosis. See Tables 2 and 3 .

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

HEAD CAPSULE AND MOUTH PARTS. Head width: 0.44–0.52 mm (see Table. 1 ). Endocarinal line present, exceeding middle of frons. Des 1 located almost in central parts of epicarnium; des 2 absent; des 3 located along frontal suture; des 4 located along frontal suture; des 5 located anterolaterally; des 4 4 times shorter than others (des 1, des 3, des 5) ( Fig. 86 ). Fs1 and fs 2 absent; fs 3 very short, located medially; fs 4 located anteromedially (along epistoma); fs 5 located anterolaterally (along epistoma), 5 times longer than fs 3 ( Fig. 86 ). Les almost equal in length as des 3. Ves 1–2 very short. Post-epicranial area with 1 minute pes. Antennal segment membranous, bearing conical sensorium and 4 very short, conical, sensilla ( Fig. 89 ).

Labrum ( Fig. 90 ) approximately 3.1 times as wide as long; lms 1 distinctly longer than equal in length lms 2 and lms 3; anterior margin slightly curved inside. Clypeus ( Fig. 90 ) 3.8 times as wide as long; with 2 pairs of very short cls of same length, and 1 sensillum, all located posterolaterally; anterior margin slightly curved inside. Epipharynx ( Fig. 91 ) with 2 pairs of als, almost of equal length; with 2 pairs of short and triangular ams; with 2 long finger-like and 1 short mes; labral rods short, kidney-shaped, slightly converging posteriorly. Mandibles ( Fig. 88 ) with 2 short mds, almost of equal length. Maxilla ( Fig. 87 ): stipes with 1 stps, and with 2 pfs of equal length; mala with 4 slightly curved dms, different in length; with 3 vms, short and almost of equal length. Maxillary palpi: length ratio of basal and distal palpomeres 1:0.7; basal palpomera with 1 short mpxs; distal palpomera with group of 4 conical, cuticular apical processes. Prementum ( Fig. 87 ) heart-shaped, with 1 prms; margin of ligula slightly sinuate; ligula with 3 lig; premental sclerite feebly visible. Postmentum ( Fig. 87 ) with 3 pairs of pms, different in length, pms 3 3 times shorter than pms 1 and pms 2.

THORAX AND ABDOMEN. Body length 3.0– 4.8 mm (see Table. 1 ), elongate. Abdominal segments I–V almost equal in length, slightly larger than abdominal segment VI and VII ( Fig. 92 ). Spiracles on abdomen in median parts of segments (abdominal seg. I–VIII).

Chaetotaxy of body developed. Setae different in length (long in comparison to other examined species), light brown. Thorax. Prothorax ( Fig. 93 ) with 8 prn, 6 macro- and 2 microsetae; 2 moderately long ps of same length; 1 eus. Meso- and metathorax ( Fig. 93 ) with 1 prs; 3 pds, almost of same length; alar area with 1 short as; 2 ss, unequal in length; 1 eps; 1 ps; and 1 short eus. Each pedal area of thoracic segments well-separated and with 4–6 long pda. Abdomen. Abdominal segments I–VII ( Fig. 94 ) with 2 prs different in length; 3 pds of different length; 2 ss; 2 eps; 2 ps of different length; 1 lsts; and 2 eus. Abdominal segment VIII ( Fig. 95 ) with 2 pds; 1 ss; 1 eps; 2 ps; 1 lsts; and 2 moderately long eus. Abdominal segment IX ( Fig. 95 ) with 1 ds; 1 ps; and 1 sts. Anal lobes on abdominal segment X ( Fig. 95 ) with 1 very short, feebly visible seta.

Description of pupa. COLORATION. Body whitish yellow.

MORPHOLOGY ( Figs. 96–98 ). Body length 1.9–2.8 mm; widest part 1.1–1.5 mm (see Table. 1 ). Body elongate, slender. Rostrum long, approximately 4.5 times as long as wide, reaching mesocoxae. Pronotum 1.6 times as wide as long.

CHAETOTAXY ( Figs. 96–98 ). Setae distinct, moderately long, unequal in length, light yellow; on pronotum and head placed on small protuberances. Head capsule including 1 vs, 2 os of different length; and 1 pas. Rostrum with 1 rs located medially. Vs and os 1 as long as setae on pronotum, distinctly longer than os 2, 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 posteromedially and posterolaterally; all abdominal setae located on small, conical protuberances. Pseudocerci very short, slightly curved inside.

Biological observations. At the time of pod collection, adults were common and some were in copula on the flowering plants, but there were several other plants with mature pods. Many pods among those collected were infested (ca. 70%) and the emergence of mature larvae was very abundant. Some pods show as many as five holes in various positions. The emergence of larvae lasted constantly for 20 days until the pods were completely dry. Then all the pods not yet naturally opened were artificially opened and in some of them 3 to 5 dead larvae were found often at different maturation instars with all the seeds eaten. Some pods contained also pupae and live adults (in a single pod two adults, two pupae and three larvae all living were found). The time of pupation was 12 days. Adults were observed first in pupal cells 13 days later. No adult left his cell during the following 30 days, then they were removed artificially. No external apparent modification of the pods was observed.

Remarks. The finding of adults in pods conserved in the laboratory was already noted by Clark & Burke (1977) for the American species T. prolixus Casey, 1892 . This is surely an aberrant behaviour due to artificial conditions. Also the high number of infested pods is not surprising since Clark & Burke (1977) collected 84% pods with larvae probably at the zenith of infestation and when also adults are found still very numerous on the flowering host plant. Tychius capucinus was also collected on several species of Lotus other than L. ornithopodioides , as L. creticus L., L. arenarius Brot. and L. collinus (Boiss.) Heldr. , usually in sand dunes near the sea, lakes and river estuaries.

Figures

FIGURES 86–91. Tychius capucinus mature larva head, antenna and mouth parts: 86—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); 87—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.); 88—right mandible (mds—mandible dorsal s.); 89—antenna; 90—labrum and clypeus (cls—clypeal s., lms—labral s.); 91—epipharynx (ams—anteromedial s., als—anteriolateral s., mes—median s., lr—labral rods).

FIGURES 92–95. Tychius capucinus mature larva habitus: 92—lateral view, 93—lateral view of thoracic segments, 94—lateral view of abdominal segment I., 95—lateral view of abdominal segments VIII–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.).

FIGURES 96–98. Tychius capucinus pupa habitus: 96—ventral view, 97—dorsal view, 98—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).