Otiorhynchus (Dorymerus) sulcatus (Fabricius, 1775)

Rafał Gosik, Peter Sprick, Jiří Skuhrovec, Magdalena Deruś & Martin Hommes, 2016, Morphology and identification of the mature larvae of several species of the genus Otiorhynchus (Coleoptera, Curculionidae, Entiminae) from Central Europe with an update of the life history traits, Zootaxa 4108 (1), pp. 1-67 : 16-19

Otiorhynchus (Dorymerus) sulcatus (Fabricius, 1775)

Material examined: 71 larvae ( Fig. 206 ). Lampertheimer Wald near Heppenheim ( Germany, South Hesse), 3 ex. introduced with young oak plants ( Quercus ilex L. and Q. frainetto Ten. ) from Italy (tree nursery) to the test area “Wald der Zukunft” of Senckenberg / Frankfurt a.M., 20.03.2010, leg. W. Dorow; Hildesheim ( Germany, Niedersachsen), nursery, 0 6.04.2011, 17 ex.: 7 ex. from Primula vulgaris flowerpots; 10 ex. from Geum chiloense Balb. ex Ser. cultivar ‘Feuerball’; dto., 0 4.05.2011, 12 ex.: 3 ex. from Eupatorium cannabinum L. flowerpots, dto., 2 ex. from Geum montanum L. cultivar ‘Diana’, dto., 7 ex. from Lysimachia clethroides Duby ; dto., 4 ex. from Primula vulgaris Huds. flowerpots, 11.05.2010; Germany, Wiesbaden (South Hesse), nursery, 27.04.2011, 21 ex.: 8 ex. from Astilbe simplicifolia Makino cultivar ‘Sprite’ flowerpots, 10 ex. from Astilbe japonica (C. Morren & Decne) A. Gray cultivar ‘Deutschland’, 3 ex. from Astilbe japonica cultivar ‘Red Sentinel’; Wiesbaden, nursery, 0 3.08.2011, 4 ex. from flowerpots with Bergenia cordifolia Sternb. cultivar ‘Glockenturm’; JKI, Braunschweig, greenhouse, 10 ex. in flowerpots with Euonymus fortunei (contamination), 13.11.2013.

Additional material: West France, Angers, 5 ex., 24.02.2012, collected by Michael Barth outdoors in a tree nursery in 15 litre plant pots with Cupressocyparis x leylandii (A.B. Jacks. & Dallim.) Dallim.. 2 larvae were reared to adults (28.– 29.03.2012) and one to pupa (pupation before 22.03.2012).

Remarks about breeding and development. The development of Otiorhynchus sulcatus is one of the best known of all soil-dwelling weevils which is due to the great impact of this species in horticulture and viticulture in many regions of the world. The damage of this species in the temperate and cooler regions to cultivated plants is mainly restricted to greenhouses, flowerpots, parks, orchards, roadside greeneries and other typical anthropogenic environments. About 110 years ago there were only few indications of a pest status of this species ( Moorhouse et al. 1992). Its origin is (northern) Italy from where also males of this predominantly parthenogenetic species are documented (concluded from data of Dieckmann 1980 and Moorhouse et al. 1992). Outdoors, pupation begins in April or May. Young weevils emerge from June to September on the soil (peak activity in July and August) and deposit eggs in this period. Larvae develop during summer and autumn, overwinter, continue feeding activity early in the season and pupate in spring. Development time of the larvae strongly depends on temperature and is over 200 days outdoors and less than 90 days in greenhouses ( La Lone & Clarke 1981). Most adults die in late summer and autumn; only a few overwinter and start to lay eggs earlier in the season. O. sulcatus did not show a diapause or developmental delay under long-day conditions in the climate chamber.

Description ( Figs. 23–33 ).

Coloration. Head dark yellow; all thoracic and abdominal segments from yellow to dark yellow; cuticle almost smooth.

Body elongated ( Fig. 23 ). Chaetotaxy: Setae different in length, filiform. Thorax. Prothorax with 4 long and 6 medium long to short prns; and 2 ps, different in length. Mesothorax with 1 short prs; 4 pds (ordered: 2 medium and 2 long); 2 as, different in length; 1 long eps; and 1 long ps. Chaetotaxy of meso- and metathorax similar (except pds, ordered: 1 medium, 1 long, 1 medium and 1 long). Each pedal area of thoracic segments well isolated, with 6 pda, different in length. Each thoracic segment with 1 short eus ( Fig. 24 ). Abdomen. Abdominal segments I–VIII with 1 short prs; 5 pds (ordered: 2 short, 1 long, 1 short and 1 long); 1 long and 1 minute sps [abd. seg. VIII only with 1 microseta]; 2 eps, different in length; 1 long and 1 minute ps; 1 long lsts; and 2 eus ( Figs. 25, 27, 28 ). Abdominal segment IX with 3 ds, different in length; 1 very long and 1 minute ps; and 2 sts, equal in length ( Figs. 26–28 ). Each of four lateral lobes of abdominal segment X with 2–3 minute ts.

Head subglobose, slightly narrowed bilaterally ( Fig. 29 ). Setae relatively short. Head capsule with 4 relatively short des, des 1 and des 2 placed on central part of epicranium, des 3 located on frontal suture, des 5 located anterolaterally; 2 relatively short fs, fs 4 placed anteromedially, fs 5 located near to antenna; 2 relatively short les; 1 relatively short ves; and 1 minute pes. Postepicranial area with 2 pairs of sensilla, forming a group. Stemmata (2 pairs) feebly visible. Antennal segment membranous, bearing 1 conical sensorium and 2–3 filiform sensilla. Clypeus 1.7 times as wide as long and with 2 cls, equal in length, placed posterolaterally on each side ( Fig. 30 ). Labrum about 2 times as wide as long with 3 straight lms of different length, placed medially or mediolaterally; lms 3 distinctly shorter than other setae, all lms exceeding the outline of the labrum; the anterior margin of labrum double sinuate ( Fig. 30 ). Epipharynx with 3 finger-like als, different in length, 3 ams, different in length, one very small ams similar to mes, but the position is more to ams; and 2 very short mes (see comments about ams and mes in Material and Methods); labral rods (lr) short, reniform, strong convergent ( Fig. 31 ). Mandible ( Fig. 32 ) feebly bifid, teeth almost of equal height; with 2 mds, different in length; internal edge with a triangular tooth. Maxilla ( Fig. 33 ) with 1 very long stps and 2 very long pfs, placed ventrolaterally; 1 very short mbs, situated ventrally. Mala with 8 dms, different in length and 4 straight vms, almost equal in length. Maxillary palpi with two palpomeres of almost equal length; basal palpomere with 1 mxps; distal palpomere with a group of 7 conical, cuticular apical processes; each palpomere with a sensillum. Praelabium heart-shaped ( Fig. 33 ), with 3 ligs and 1 prms. Labial palpi with two palpomeres, relatively elongated; both palpomeres almost equal in length; praemental sclerite well visible. Postlabium with 3 pms, different in length; pms 2 long, almost 2 times as long as pms 1 and pms 2 ( Fig. 33 ).

Differential diagnosis. See “Key to larvae of selected Otiorhynchus species” and Tables 1, 2.

Figures

FIGURES 203 – 210. Mature larva, lateral view. 203 — O. indefinitus, 204 — O. raucus, 205 — O. ligustici, 206 — O. sulcatus, 207 — O. porcatus, 208 — O. singularis, 209 — O. armatus, 210 — O. armadillo. (Photos by R. Gosik).

FIGURES 23 – 28. Otiorhynchus sulcatu s; mature larva. 23 — habitus, lateral view, 24 — lateral view of thoracic segments, 25 — lateral view of abdominal segment I, 26 — lateral view of abdominal segments VIII – IX, 27 — ventral view of abdominal segments VIII – X, 28 — dorsal view of abdominal segments VIII – X. Abbreviations: Ab. — abdominal segment, Th. — thoracic s., I – X—number of segments, prns — pronotal seta (e), prs — prodorsal s., pds — postdorsal s., pda — pedal s., as — alar s., lsts — laterosternal s., eus — eusternal s., ps — pleural s., sps — spiracular s., sts — sternal s., ds — dorsal s., ts — terminal s.

FIGURES 29 – 33. Otiorhynchus sulcatus; mature larva and mouthparts. 29 — dorsal view of head, 30 — labrum and clypeus, 31 — epipharynx, 32 — left mandible, 33 — maxillo-labial complex. Abbreviations: des — dorsoepicranial seta (e), fs — frontal s., les — lateroepicranial s., ves — ventroepicranial s., pes — postepicranial s., at—antenna, st—stemmata, cls — clypeal s., lms — labral s., ams — anteromedial s., als — anterolateral s., mes — medial s., lr—labral rods, mds — mandible dorsal s., dms — dorsal malae s., vms — ventral malae s., mxps — maxillary palps s., pfs — palpiferal s., stps — stipal s., mbs — mandible basiventral s., prms — prelabial s., pms — postlabial s., ligs — ligular s., so — sensory organ.