Otiorhynchus (Zustalestus) rugosostriatus (Goeze, 1777)

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 : 48-53

Otiorhynchus (Zustalestus) rugosostriatus (Goeze, 1777)

Material examined: 7 larvae ( Figs. 219 , 228 ). Larvae were obtained from a field with a large population at Wiesbaden-Schierstein ( Germany, South Hesse), where the ornamental grass Panicum virgatum L. was grown ( Figs. 223, 225 ), and from two breeding attempts in the climate chamber of the JKI in Braunschweig. Despite the data on the pest status in strawberry fields, breeding in flowerpots with different plants proved to be difficult and revealed only one time a small number of mature larvae: JKI, breeding in flowerpots with Dendranthema x grandiflorum, 3 ex. on 0 5.01.2012, and 4 ex. were collected in the above-mentioned field in Wiesbaden on 28.04.2011.

Remarks about breeding and development. The life-cycle of the “Rough Strawberry Root Weevil” is rather simple, and Wilcox et al. (1934) were the first who reported about it in detail. It is widely confirmed by current studies in Wiesbaden-Schierstein (see Sprick 2012, in Sprick & Stüben 2012). Wilcox et al. (1934) stated that this weevil emerges about 2 weeks later in the season than Otiorhynchus ovatus and that oviposition is delayed until August and September. By this, it is the species with the latest egg-laying activity of all Otiorhynchus species in which this has been studied. Wilcox et al. (1934) also report that some adults do overwinter, too, but that there are also sites without overwintering adults. In Wiesbaden-Schierstein overwintering adults and mature larvae were found in spring (larvae in April and May) and a few pupae and a newly hatched, white-colored adult on 31.05.2014 (Sprick 2012, in Sprick & Stüben 2012) ( Fig. 230 ). Only one month later no more pupae or larvae could be found, despite of an intensive search at this locality with very high abundance of adult weevils. Young adults were found from June to mid-July and very rarely later in the season. Apparently there is a delay in egg deposition as Otiorhynchus species usually do not need more than 3 weeks to start with oviposition after emerging on the soil surface.

Body part Setal code A B C D E F G H I J K L M N

Head capsule des (dοrsal epicranial) 4 4 4 4 4 4 4 4 4 4 4 4 4 4 fs (frοntal epicranial) 2 2 2 2 2 2 2 2 2 2 2 2 2 2 les (lateral epicranial) 2 2 2 2 2 2 2 2 2 2 2 2 2 2 ves (ventral epicranial) 1 1 1 1 1 0 1 1 1 1 1 2 2 1 pes (pοsteriοr epicranial) 0 0 1 0 0 0 0 0 0 0 0 0 0 1 lms (labral) 3 3 3 3 3 3 3 3 3 3 3 3 3 3 cls (clypeal) 0 2 2 2 2 1 1 2 2 2 2 1 1 2 mds (mandibular) 2 2 2 2 2 2 2 2 2 2 2 2 2 2

Epipharynx als (anterοlateral) 3 3 3 3 3 3 3 3 3 3 3 3 3 3 ams (anterοmedial) 2 2 3 3 2 3 3 2 2 2 2 2 3 2 mes (medial) 2 1 2 2 2 2 2 2 2 2 2 2 2 2

Maxilla dms (dοrsal malar) 7 7 8 6 6 5 4 7 7 7 6 5 7 6 vms (ventral malar) 4 4 4 4 3 4 3 4 4 4 4 4 3 4 stps (stipital) 1 1 1 1 1 1 1 1 1 1 1 1 1 1 pfs (palpiferal) 2 2 2 2 2 2 2 2 2 2 2 2 2 2 mbs (malar basiventral) 1 1 1 1 1 1 1 1 1 1 1 1 1 1 mxps (maxillary palpal) 1 1 1 1 1 1 1 1 1 1 1 1 1 1

Labium prms (premental) 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ligs (ligular) 2 2 2 2 2 2 1 2 2 2 2 2 2 2 so (sensοry οrgan) 0 0 1 0 0 0 0 0 0 0 0 0 1 0 pms (pοstmental) 3 3 3 3 3 3 3 3 3 3 3 3 3 3

Prothorax prns (prοnοtal) 7 10 10 9 8 8 9 9 8 9 9 10 7 8 prns1 (macrοsetae) 4+3 5+5 4+6 3+6 4+4 4+4 4+5 4+5 4+4 4+5 4+5 4+6 6+1 4+4 prns2 (micrοsetae) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ps (pleural) 2 2 2 2 2 2 2 2 2 2 2 2 2 2 eus (eusternal) 1 1 1 1 1 1 1 1 1 1 1 1 1 1 pda (pedal area) 5 5 6 5 5 4 4 4 5 5 5 5 6 4 ......continued on the next page Description ( Figs. 144–154 ).

Coloration. Head light brown; all thoracic and abdominal segments from dirty yellow to brown.

Body elongated ( Fig. 144 ). Chaetotaxy: Setae different in length, relatively long, filiform, bicolored (basal part brownish, apical white). Thorax. Prothorax with 4 long and 4 medium long to short prns; and 2 ps, different in length. Mesothorax with 1 medium long prs; 4 pds (ordered: 2 medium long, 1 long and 1 medium long); 1 medium long as; 1 medium long eps; and 1 long ps. Chaetotaxy of meso- and metathorax similar, except pds (ordered: 1 medium long, 1 long and 2 medium long). Each pedal area of thoracic segments well isolated, with 5 pda, different in length. Each thoracic segment with 1 short eus ( Fig. 145 ). 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 minute sps and 4 pds (1 long, 1 very short, 1 long, and 1 medium long)]; 2 eps, different in length; 1 long and 1 minute ps; 1 medium long lsts; and 2 eus ( Figs. 146, 148, 149 ). Abdominal segment IX with 3 ds, different in length; 1 ps very long; and 2 sts, equal in length ( Figs. 147–149 ). Lateral lobes of abdominal segment X with 2–3 minute ts each.

Head subglobose, slightly narrowed bilaterally ( Fig. 150 ). Head capsule with 4 long des, des 1 and des 2 placed on central part of epicranium, des 3 located on frontal suture, des 5 located anterolaterally; 2 long fs, fs 4 placed anteromedially, fs 5 located near to antenna; 2 long les; 1 short ves; and 1 minute pes; all des, les and fs equal in length. Stemmata (2 pairs) well visible. Antennal segment membranous, bearing 1 conical sensorium and 2–3 filiform sensilla. Clypeus 3.7 times as wide as long with 2 cls, placed anterolaterally ( Fig. 151 ). Labrum about 2 times as wide as long with 3 straight lms of different length, placed medially or mediolaterally; lms 2 distinctly longer than other setae, lms 1 and lms 3 only a little exceeding the outline of the labrum; the anterior margin of labrum double sinuate ( Fig. 151 ). Epipharynx with 3 finger-like als, different in length; 2 ams, different in length; and 2 very short mes, labral rods (lr) elongated, almost parallel; surface of epipharynx densely covered by triangular, cuticular processes ( Fig. 152 ). Mandible ( Fig. 153 ) feebly bifid, teeth almost of equal height; with 2 mds, different in length; internal edge with a small triangular tooth. Maxilla ( Fig. 154 ) with 1 very long stps and 2 very long pfs, placed ventrolaterally; 1 very short mbs, situated ventrally. Mala with 6 dms, different in length and 4 vms, straight, almost equal in length. Maxillary palpi with two palpomeres; basal palpomere a little larger than distal; basal palpomere with 1 mxps; distal palpomere with a group of 7 conical, cuticular processes apically; each palpomere with a sensillum. Praelabium heart-shaped ( Fig. 154 ), with 2 very short ligs and 1 long prms. Labial palpi with two palpomeres, relatively elongated; basal palpomere longer than distal; praemental sclerite well visible. Postlabium with 3 pms, different in length; pms 2 very long, at least 5 to 6 times as long as pms 1 and pms 3 ( Fig. 154 ).

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

Figures

FIGURES 211 – 219. Mature larva, lateral view. 211 — O. aurifer, 212 — O. meridionalis, 213 — O. clavipes (= O. tenebricosus), 214 — O. fuscipes (= O. tenebricosus), 215 — O. lugdunensis, 216 — O. salicicola, 217 — O. ovatus, 218 — O. crataegi, 219 — O. rugosostriatus. (Photos by R. Gosik).

FIGURES 226 – 231. Breeding and collecting of the weevil larvae. 226 — O. aurifer larvae from breeding in the climate chamber, 227 — O. crataegi larva and pupa in the field—size compared with a Taxus needle, 228 — O. rugosostriatus larva in the Panicum virgatum field in Wiesbaden-Schierstein, 229 — O. rugosostriatus, young adult, just hatched, found under Panicum virgatum, as before, 230 — O. armatus, 2 mature larvae on graph paper, 231 — O. armadillo larva in a flowerpot used for breeding. (Photos by P. Sprick).

FIGURES 220 – 225. Breeding and collecting of the weevil larvae. 220, 222 — Sampling sites of O. crataegi under Taxus in Bad Zwischenahn, 221 — Breeding of O. armadillo in flowerpots with Euonymus fortunei cultivar Emerald ' n Gold, 223, 225 — Sampling sites of O. rugosostriatus under Panicum virgatum in Wiesbaden-Schierstein, 224 — Breeding of O. aurifer in a flowerpot with Viburnum tinus. (Photos by P. Sprick).

FIGURES 144 – 149. Otiorhynchus rugosostriatus; mature larva. 144 — habitus, lateral view, 145 — lateral view of thoracic segments, 146 — lateral view of abdominal segment I, 147 — lateral view of abdominal segments VIII – IX, 148 — ventral view of abdominal segments VIII – X, 149 — 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 150 – 154. Otiorhynchus rugosostriatus; mature larva and mouthparts. 150 — dorsal view of head, 151 — labrum and clypeus, 152 — epipharynx, 153 — left mandible, 154 — 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.