Anthonomus (s. str.) incurvus (Panzer, 1795)

Zabulev, Ilya A., 2021, Contribution to the knowledge of the immature stages of Palaearctic species of the genus Anthonomus Germar (Coleoptera: Curculionidae), Zootaxa 5032 (4), pp. 451-488 : 463-467

Anthonomus (s. str.) incurvus (Panzer, 1795)

Figs. 37–50 , 101 .

Material examined. 8 larvae and 6 pupae, 10.06.1940, Russia, Leningrad region, Gatchina, ex flower buds of Padus , leg. D.A. Ogloblin, det. I.A. Zabaluev ( ZISP) ; 18 larvae and 8 pupae, 15– 22.05.2021, Russia, Saratov region, environs of the railway station « 55 km » (51.224533°N 45.534377°E), ex flower buds of Cerasus vulgaris Mill. , leg. and det. I.A. Zabaluev ( IZCS) .

Description of mature larva. Figs. 37–47 .

Measurements (from Padus ) (in mm). Body length: 2.87–3.38 (mean 3.13). Body width: 1.16–1.27 (mean 1.22). Head width: 0.58–0.60 (mean 0.59).

Measurements (from Cerasus ) (in mm). Body length: 3.33–4.11 (mean 3.75). Body width: 1.53–1.67 (mean 1.61). Head width: 0.67–0.70 (mean 0.68).

Body from whit to light yellow, distinctly C-shaped curved ( Fig. 37 ). Pronotum with distinct brown shield. Spiracles ( Fig. 38 ) bicameral, air tubes with five or six annuli (one specimen with four on some abdominal segments), one pair located on the prothorax, and eight pairs located laterally on the abdominal segments I–VIII (Ab1–8). All setae of thoracic and abdominal segments hairlike, from long to minute, brownish - yellow. Prothorax (Th1) ( Fig. 39 ) with ten prns of unequal length (prns 1 —medium, prns 6 —very short, other—from long to very long), two very long ps equal length and two eus (short and minute). There are two distinct sensilla—one located near the base of prns 1, other—medially. Meso- (Th2) and metathorax (Th3) ( Fig. 39 ) with two prs (short and minute), four pds different in length (pds 1, pds 3, and pds 4 —long; pds 2 —short), one short as, three ss (long, short and minute), one very long eps, one very long ps and two eus (short and minute). Pedal lobe with five pda: pda 1 – 4 long, subequal length, pda 5 minute and located close to the anterior edge of the segment. Pedal lobe without sensillum in specimens from Padus and with one distinctly sensillum in specimens from Cerasus . Abdominal segments I–VIII (Ab1–8) ( Fig. 40 ) with two prs (short and minute), five pds different in length (pds 1, pds 3, and pds 5 —long; pds 2 and pds 4 —short), three ss (long, short and minute), two eps (long and very long), one long ps, one medium lsts and three eus (two very short and one minute). Abdominal segment IX (Ab9) ( Fig. 41 ) with seven fine setae dorsally (ds), two ps (long and short) and one short sts. Abdominal segment X (Ab10) without setae.

Head capsule ( Figs. 37 , 42 ) dark brown, strongly sclerotized, rounded rectangular shape. Endocarinal line present, reaching behind middle of the frons and about 2/3 as long as frons. Frontal sutures distinct, extending to antennae. One stemma (st) present close to antenna. Dorsal setae (five des): des 1 and des 2 short, des 3 and des 5 long, des 4 fine and very short; des 1 and des 2 located near to middle part of epicranium, des 3 close to frontal suture, des 4 on laterally of des 3, des 5 —anterolaterally. There is one dorsal sensillum between des 4 and des 5. Frontal area with four fs: fs 1 and fs 3 minute and inconspicuous, fs 2 absent, fs 4 long, located anterolaterally, fs 5 very long, located laterally, close to the border of frons, and with two sensilla—one is between fs 1 and fs 3, closer to the median line, the other is between fs 3 and fs 4 slightly displaced towards the frontal suture. Lateral setae: les 1 and les 2 very long (les 1 as long as fs 5, les 2 slightly shorter than les 1). Ventral setae: two short vcs. Posterior epicranial area with four minute pes: pes 2-4 arranged in a row, pes 1 —at the side edge, and with two sensilla—one is between pes 3 and endocarinal line and the other near des 1. Antenna ( Figs. 43 , 101 ) is one-segmented, consisting of a basal membranous segment bearing an elongate-conical porous sensorium (se) and six sensilla: three styloconium (ss) and three basiconicum (sb).

Clypeus and mouthparts. Clypeus ( Fig. 44 ) trapezium - shaped, with two very short cls placed close to anterior margin of frons and one clypeal sensillum (clss) located between them. Labrum ( Fig. 44 ) with three lrs: lrs 1 and lrs 2 long, subequal length, lrs 3 short, about 1/2 as long as lrs 1. Epipharynx ( Fig. 45 ) with two piliform ams (ams 1 one much longer than ams 2), three finger-like als and two short mes. Labral rods (lr) moderately long, quite broad, converging slightly posteriorly. One sensillum located on both sides of lr and four combined in a single median cluster (esc). Mandibles ( Fig. 46 ) stout, strongly sclerotized, triangular, with two apical teeth, mds subequal length, mandibular sensillum located medially. Maxilla ( Fig. 47 ) with one very long stps, two pfs (pfs 2 about 2/3 as long as pfs 1), very short mbs and two sensilla. Mala on dorsal side with a row of four finger-like dms, on ventral side with five thin acuminate vms (three comparatively long and two comparatively short). Maxillary palpi consists of two palpomere; basal palpomere with one short mxps and two sensilla, distal—with one simple sensillum, one digitiform sensillum (sd) laterally, and eleven basiconicum sensilla (sb) at the apex. Prelabium cup-like with four sensilla and one medium prms; ligula with three ligs. Labial palpi elongated, one-segmented, with one sensillum medially and eight or nine basiconicum sensilla (sb) at the apex. Postlabium with three pms: pms 1 — long, about 2.5x as long as pms 3, pms 2 — very long, pms 3 — short.

Description of pupa. Figs. 48–50 .

Measurements (from Padus ) (in mm). Body length: 2.82–2.96 (mean 2.89). Body width: 1.22–1.26 (mean 1.24). Head width: 0.51–0.53 (mean 0.52).

Measurements (from Cerasus ) (in mm). Body length: 2.80–3.49 (mean 3.12). Body width: 1.29–1.60 (mean 1.50). Head width: 0.53–0.56 (mean 0.54).

Coloration. From yellowish white to brownish yellow.

Body. Rostrum long, 3.5–4.1x as long as wide in male, and 4.3–4.5x in female. Pronotum transverse, 1.5–1.7 times as wide as long. Prothoracic depressions lacking. Spiracles well developed on Ab1–5, and vestigial on Ab6.

Chaetotaxy. Setae yellowish, hair-like, slightly curved, from long to minute. Head capsule only with one very short and thin vs. Rostrum without setae. Pronotum (Th1) with one as, two ds, two sls, and three pls; as 1 minute, located subapically on anterior surface of the conical tubercle; ds 1 minute, located subapically on anterior surface of the large conical tubercle, which larger than those elsewhere on pronotum; ds 2 long, as long as pls 3, located at the base of a large, pointed tubercle; sls 1-2 thin, approximately equal length, located near bases of small pointed tubercles; pls 1-3 arranged in the form of a semicircular row, thin and rather long, pls 3 located at the base of a small acute tubercle, the others—on more rounded tubercles. Femora without fes. Meso- (Th2) and metanotum (Th3) with three long and relatively stout dorsal setae (d) placed medially, they begin in the middle of flat rounded convexes. Abdominal tergites (Ab1–8) with three distinct dorsal setae (d), d 1 slightly thinner and shorter than others, d 2 and d 3 approximately equal length, only d 3 on Ab7–8 located at the bases of small tubercles. L t 1 minute, located directly above the spiracles, on Ab 1–5 in a slight depression, on Ab6–8 at the bases of small tubercles (rounded on Ab6 and pointed on Ab7–8); lt 2 long, located at the middle of the lateral margin of tergum, on Ab1–5 on flat tubercles, on Ab6–8 near the bases of protruding tubercles and their size increases from Ab6 to Ab8; ls 1 short; ls 2 long, both setae located close to each other almost immediately below lt 2. Abdominal sternites (Ab1–8) with one fine very short ventral seta (v). Urogomphi paired, highly sclerotized, long, diverging from each other at an angle of 40–50 degrees, almost straight, not curved outward at the apex. Ab9 ( Fig. 49 ) with two very short and fine setae: v placed ventrolaterally, lt placed laterally; urogomphi ( Fig. 49 ) also with two very fine setae: d 1 short, located dorsally at the base of urogomphi, d 2 very short, located dorsally in the middle of the length of urogomphi. In addition, there is one minute seta next to each seta (except for lt), but these setae are unstable and not present in all specimens.

Biology. According to published data, this species usually lives on Padus avium Mill. , less often on Padellus mahaleb (L.) Vassilcz., Cerasus avium (L.) Moench, C. fruticosa Pall. , C. vulgaris ( Scherf 1964; Dieckmann 1968; Smreczyński 1976; Dedyukhin 2012).

Figures

FIGURES 37–41. Anthonomus incurvus, mature larva. 37—habitus of the body and frontal view of head, 38—thoracic spiracle, 39—lateral view of thoracic segments, 40—lateral view of abdominal segment I, 41—lateral view of abdominal segments VIII–X (setae: as—alar, ds—dorsal, eps—epipleural, eus—eusternal, lsts—laterosternal, pda—pedal, pds—postdorsal, prns— pronotal, prs—prodorsal, ps—pleural, ss—spiracular, sts—sternal).

FIGURES 42–47. Anthonomus incurvus, mature larva head and mouthparts. 42—head, frontal view, 43—antenna, 44—clypeus and labrum, 45—epipharynx, 46—left mandible, 47—maxillolabial complex, ventral aspect (apical part of the right maxilla is shown in dorsal aspect) (at—antenna, clss—clypeal sensilla, esc—epipharyngeal sensilla cluster, lr—labral rods, st—stemma; setae: als—anterolateral, ams—anteromedial, cls—clypeal, des—dorsal epicranial, dms—dorsal malar, fs—frontal, ligs—ligular, lrs—labral, ls—lateral epicranial, mbs—basiventral malar, mds—mandibular, mes—median, mxps—maxillary palp, pes— postepicranial, pfs—palpiferal, pms—postlabial, prms—prelabial, stps—stipal, vms—ventral malar).

FIGURES 48–50. Anthonomus incurvus, pupa habitus and chaetotaxy. 48—ventral view, 49—dorsal view, and urogomphi (the left half—dorsally, the right half—ventrally, increased two times), 50—lateral view (Th1–3—number of thoracic segments, Ab1–9—number of abdominal segments, sp—spiracle; setae: as—apical, d—dorsal, ds—discal, ls—laterosternal, lt—laterotergal, pls—posterolateral, sls—superlateral, v—ventral, vs—vertical).

FIGURES 98–106. Antennae and maxillary palpi of Anthonomus (SEM images). 98—A. pinivorax, 99—antenna of A. rubripes, 100—maxillary palp of A. rubripes, 101—A. incurvus, 102—A. conspersus, 103—A. latior, 104—A. pedicularius, 105—A. pomorum, 106—A. rubi (se—sensorium, sa—sensilla ampullacea, sd—sensilla digitiform, ss—sensilla styloconium, sb—sensilla basiconicum). Scale bars 10 μm.