Peritelus sphaeroides

Gosik, Rafal, Sprick, Peter & Morris, Michael G., 2019, Descriptions of immature stages of four species of the genera Graptus, Peritelus, Philopedon, and Tanymecus and larval instar determination in Tanymecus (Coleoptera, Curculionidae, Entiminae), ZooKeys 813, pp. 111-150 : 119-123

Peritelus sphaeroides

Specimens examined.

Rearing was started on 02.05.2012 in the climate chamber of JKI in flowerpots with mainly Euonymus fortunei (Turcz.) Hand.-Mazz. and one with Prunus laurocerasus L. Adults had been collected 5 days previously in a hedgerow with ornamental shrubs in the JKI area.

3 premature larvae: flowerpot with Euonymus fortunei , climate chamber, JKI, 13.12.2012: 2 ex. These specimens were bred to produce pupae and transferred to Hannover for regular pupal control. As there was no further development, they were taken out on 25.01.2013; flowerpot with Prunus laurocerasus , climate chamber of JKI, 14.03.2013: 1 ex.

12 mature larvae: flowerpot with Euonymus fortunei , JKI, climate chamber, 24.08.2012: 1 ex. (the first mature larva after 3 months and 3 weeks of development), 01.11.2012: 2 ex., do., 13.12.2012: 5 ex. (4 of them were used for regular pupae control; as there was no pupation, they were taken out on 25.01.2013), 14.03.2013: 2 ex., flowerpot with Prunus laurocerasus , JKI, climate chamber, 14.03.2013: 2 ex.

Description of mature larva.

Body length: 6.5-7.7 mm, body width at the widest part (level of first abdominal segment): 2.0-2.5 mm, head width: 1.10-1.17 mm, head height: 0.90-1.00 mm.

Body (Figs 4-6). Slender, curved, rounded in cross section. Prothorax slightly smaller than mesothorax; metathorax as wide as mesothorax. Abdominal segments 1-6 of almost equal length; 7-9 decreasing gradually to the terminal parts of the body; 10 reduced to 4 anal lobes of various sizes (ventral lobe the smallest, dorsal the largest) (Fig. 6). Spiracles (of thoracic and abdominal segments 1-8) annular. Chaetotaxy well developed; setae capilliform, variable in length, dark yellow to brown. Each side of prothorax (Fig. 28) with 9 prns of different length; 2 ps and 1 eus. Meso- and metathorax (Fig. 28) on each side with 1 moderately long prs, 4 pds, variable in length (first, third and fourth long, second short), 1 long as, 2 moderately long ss, 1 moderately long eps, 1 moderately long ps and 1 eus. Each pedal area of thoracic segments with 4 pda, variable in length. Abd. 1-7 (Fig. 27) on each side with 1 short prs, 5 pds, varied in length (first, second and fourth very short, third and fifth long) and arranged along the posterior margin of each segment, 1 minute and 1 long ss, 2 eps and 2 ps of varied lengths, 1 lsts and 2 short eus. Abd. 8 (Figs 30-32) on each side with 1 short prs, 4 pds of varied length (first and third moderately long, second and fourth long) and all arranged along posterior margin of the segment, 1 minute ss, 2 eps and 2 ps of various length, 1 lsts and 2 short eus. Abd. 9 (Figs 30-32) on each side with 4 ds (dorsal setae): first, second and fourth short, third moderately long, all located close to posterior margin of the segment, 1 long ps and 2 short sts. Each lateral anal lobe (Abd. 10) with a pair of minute terminal setae (ts).

Head (Fig. 33). Light to dark yellow, slightly narrowed bilaterally, frontal suture distinct, Y-shaped, endocarina absent. Setae on head capilliform; des1, 2, 3, 5 equal in length; des1 and des2 located in the central part of epicranium, des3 placed on frontal suture, des5 located anterolaterally; fs4, 5 almost equal in length, fs4 located anteromedially, fs5 anterolaterally, close to epistome; les1 and les2 equal in length, slightly shorter than des1. Postepicranial area with 7 very short pes. Single ves very short (Fig. 33). Stemmata poorly visible, located close to des5. Antenna (Fig. 34) located at the end of frontal suture; antennal segment membranous, bearing cushion-like sensorium (Se), located medially and 4 sensilla of different types: 1 ampullaceum (sa) and 3 basiconica (sb). Clypeus (Fig. 35) trapezoid, anterior margin of clypeus slightly emarginate at the inside; 2 pairs of cls very short, located posteromedially; clss clearly visible, placed medially between cls. Labrum (Figs 35, 36) almost semicircular, anterior margin rounded; 3 pairs of lrs of different length, lrs1 and lrs3 moderately long, lrs2 very long, all lrs reaching behind anterior margin of labrum; lrs1 placed medially, lrs2 anteromedially, lrs3 anterolaterally. Epipharynx (Figs 37, 38) with 3 pairs of finger-shaped als of almost equal length; 3 pairs of ams: ams1 and ams3 rod-shaped, very short, ams2 finger-like, very long; 2 pairs of rod-shaped mes, equal in length. Surface of epipharynx covered with asperities. Labral rods elongate, converging posteriorly. Mandibles (Figs 39, 40) elongate, narrow, with divided apex (teeth variable in length). There is a protruding additional tooth on the cutting edge between the apex and the middle of the mandible; single mds capilliform, moderately long. These characters can disappear due to intensive feeding and gradual wear and tear of mandibles (Fig. 40). Maxilla (Figs 41-43) with 1 stps and 2 pfs of equal length; mala with 7 finger-like dms (Fig. 42) and 4 vms, all of varied length, the latter only slightly shorter than dms (Fig. 43); mbs short. Maxillary palpi with 2 palpomeres, basal with short mps; distal palpomere apically with a group of sensilla, each palpomere with a pore. Basal palpomere distinctly wider and longer than distal. Prelabium (Fig. 41) cup-like with 1 very long prms, located medially. Ligula with 2 pairs of ligs: first relatively long, second minute. Premental sclerite clearly visible, trident-shaped, posterior extension with thickened apex. Labial palpi 2-segmented; apex of distal palpomere with some sensilla; each palpomere with a pore. Basal palpomere distinctly wider and slightly longer than distal. Postlabium (Fig. 41) with 3 capilliform pms, the first pair located anteromedially, the remaining 2 pairs posterolaterally: pms1 moderately long, pms2 twice as long aspms1 and pms3 short.