Otiorhynchus singularis

Distinguished from the vine weevil (O. sulcatus) and strawberry root weevil (O. ovatus) by its clay-brown coloration and specific elyral sculpturing, though variation makes reliable field identification difficult. Examination of genitalia or expert verification is often required for definitive identification. Differs from Phyllobius and Polydrusus genera by the position of antennal insertion on the rostrum and overall body proportions.

Adults are clay-coloured to brown weevils with a compact, oval body form typical of the genus. The elytra bear distinct longitudinal grooves (striae). Like all Otiorhynchus species, they possess a pronounced rostrum (snout) with elbowed, clubbed antennae inserted partway along its length. Colour and morphology can vary considerably between individuals, complicating identification.

Found in gardens, orchards, hop yards, conifer plantations, and natural woodland edges. Associated with the root zones of host plants where larvae develop in soil.

Native to Europe; introduced and established in British Columbia (Canada), Connecticut (USA), and the Azores (São Miguel). European records span from western to eastern regions.

Adults are active from spring through autumn, with peak activity during warmer months. Nocturnal feeding habits mean adults are most commonly encountered after dusk.

Adults feed on buds, young shoots, and leaves of currants, gooseberries, raspberries, hops, firs, and Norway spruce. Larvae feed on roots in soil; specific larval host range is poorly documented but presumed to overlap with adult hosts.

• Ribes spp. - feeds oncurrants and gooseberries
• Rubus idaeus - feeds onraspberry
• Humulus lupulus - feeds onhops
• Abies spp. - feeds onfir trees
• Picea abies - feeds onNorway spruce

Reproduces parthenogenetically; females lay eggs in soil near host plants. Larvae are soil-dwelling, feeding on roots, and pupate in the soil. Development likely spans one year, with adults emerging in spring, though specific timing varies by region.

Nocturnal. Adults hide in soil or debris at the base of host plants during daylight hours. When disturbed, adults drop to the ground and feign death. Adults are flightless.

Acts as a folivore and root herbivore, capable of causing measurable damage to cultivated plants and young conifers. Soil-dwelling larvae contribute to nutrient cycling through root decomposition.

Recognized agricultural and horticultural pest, particularly damaging to soft fruit bushes, hops, and conifer nursery stock. Damage includes defoliation, bud destruction, and bark chewing. Introduced populations in North America represent an invasive species of economic concern.

• Otiorhynchus sulcatusVine weevil shares similar body form and habits but typically darker (black) with more pronounced punctation on elytra; both are parthenogenetic root-feeding pests.
• Otiorhynchus ovatusStrawberry root weevil is smaller with different rostral proportions and elyral sculpture; also parthenogenetic and nocturnal.
• Phyllobius spp.Distinguished by antennal insertion near rostral tip rather than midpoint, and typically more metallic coloration.
• Polydrusus spp.Generally more brightly coloured (metallic greens/blues) with different antennal club structure and diurnal activity pattern.

• parthenogenetic
• flightless
• nocturnal
• pest
• introduced
• root feeder
• polyphagous

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy