Otiorhynchus desertus, Rosenhauer, 1847

Lewis, Jake H. & Anderson, Robert S., 2022, Otiorhynchus desertus Rosenhauer, 1847 (Coleoptera: Curculionidae): Confirmation of Establishment in North America, and Other New Provincial Records of Adventive Weevils from New Brunswick, Canada, The Coleopterists Bulletin 76 (3), pp. 441-444 : 441-442

OTIoRHYnCHUS DESERTUS Rosenhauer, 1847

NEW BRUNSWICK: Saint John County, Saint John, near Rockwood Park (45.3208°N, 66.0693°W), 7 July 2021, J. H. Lewis, collected in mixed forest litter sift (1 adult, Canadian Museum of Nature Collection [CMNC], Fig. 1A ); Victoria County, Four Falls (46.8390°N, 67.7332°W), 1 January 2022, J. H. Lewis, dead specimen collected from spiderweb in private garage in agricultural area (1 adult, CMNC); York County, forest edge along Trans-Canada Highway 2 near Longs Creek (45.870826°N, 66.977759°W), 18 February 2022, J. H. Lewis, overwintering specimen taken from litter sift along highway in Acer L. ( Sapindaceae )/ Populus L. ( Salicaceae )/ Betula L. ( Betulaceae ) forest (1 adult, CMNC); NEWFOUNDLAND: St. John’s, Oxen Pond Botanic Garden, 9 September 1997, D. Langor (1 adult, Memorial University of Newfoundland Insect Collection [MUN]), Accession No. 12-395; St. John’s, Pippy Park, 17 June 1981, D. Langor (1 adult, MUN), Accession No. 17-17589; ONTARIO: Leeds and Greenville County, Chaffey’s Lock, Queen’s University Biological Station (44.5652°N, 76.3238°W), 18 June 2015, Monica R. Young, from soil and leaf litter in Berlese funnel trap (2 larvae, Centre for Biodiversity Genomics [CBG]), BIOUG23254-A03, BIOUG23254-A04 (BOLD sample IDs; both specimens destroyed in DNA extraction process); Bruce County, Black Creek Provincial Park, Sandy Shore Road (44.9681°N, 81.3625°W), 21 July 2015, BIObus surveyors, collected from litter in conifer forest in Berlese funnel trap (1 first instar larva, CBG), BIOUG26321-H02 (BOLD sample ID).

Otiorhynchus desertus occurs naturally throughout Europe ( Alonso-Zarazaga et al. 2017); however, little is known of the ecology or host plant preferences of this species ( Morris 1997). This species has been associated with mountainous habitats in Europe and adults have been collected from mosses in subalpine meadows ( Morris 1997; Warner and Negley 1976). Morris (1997) asserted that the species is likely nocturnal and noted that O. desertus prefers light soils with denser vegetation than the closely related Otiorhynchus ovatus (Linnaeus, 1758) , and that these species rarely occur together. Lindroth (1957) reported O. desertus from Cape Broyle, Newfoundland based on a specimen collected in 1949 (see Bright and Bouchard 2008). However, Bright and Bouchard (2008) asserted that this specimen is a worn or aberrant specimen of O. ovatus and that the presence of O. desertus in North America was therefore uncertain. Specimens of O. desertus collected in North America were compared with CMN specimens of O. ovatus and British Natural History Museum (BNHM) specimens of O. desertus . The newly reported O. desertus ( Fig. 1A ) differs morphologically from O. ovatus ( Fig. 1B ) in the following ways: O. desertus possesses (1) a single, medial carina on the pronotum (multiple ridges in O. ovatus ), (2) elytral hairs occurring more densely and less evenly (evenly distributed in O. ovatus , without distinct clusters), (3) a smaller, less distinctly notched bifid tooth on the profemur (large and clearly notched in O. ovatus ), (4) a small- er tooth on the hind femur (larger in O. ovatus ), and (5) duller elytra (Bright and Bouchard 2008; Morris 1997). Barcode (CO1) sequences obtained from the larval specimens of O. desertus collected in Ontario match closely with barcodes obtained from European representatives of the species, with <1% sequence divergence between members of the O. desertus clade (BOLD: ACJ6037) and a high degree of sequence divergence from the nearest clade ( O. ovatus [BOLD: AAG5198];> 13% sequence divergence). The collection of adults and larvae in non-targeted insect surveys at multiple, well-separated localities suggests that O. desertus is likely established in eastern Canada. Targeted field surveys emphasizing night collecting on vegetation in suitable habitats should help determine the extent of the geographic range of the species in the region.

Figures

Fig. 1. Dorsal habitus. A) Otiorhynchus desertus collected near Rockwood Park, Saint John, New Brunswick, Canada (note the single medial carina on the pronotum, less evenly distributed elytral hairs, and duller elytra), B) O. ovatus for comparison.