Clay-Coloured Weevil vs Coastal Ragweed

Otiorhynchus singularis compared with Ambrosia hispida

Taxonomic Classification

Rank	Clay-Coloured Weevil	Coastal Ragweed
Kingdom	Animalia (Animals)	Plantae (Plants)
Phylum	Arthropoda (Arthropods)	Magnoliophyta (Flowering Plants)
Class	Insecta (Insects)	Magnoliopsida (Dicots)
Order	Coleoptera (Beetles)	Asterales (Daisies & Sunflowers)
Family	Curculionidae	Asteraceae (Daisy Family)
Genus	Otiorhynchus	Ambrosia
Species	Otiorhynchus singularis	Ambrosia hispida

Conservation Status

Clay-Coloured Weevil

LC — Least Concern

Coastal Ragweed

LC — Least Concern

Physical Characteristics

Attribute	Clay-Coloured Weevil	Coastal Ragweed
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Clay-Coloured Weevil

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Found across Europe (32 countries) and North America (Canada, United States).

Coastal Ragweed

Habitat

Typically found in diverse terrestrial habitats from tropical forests to temperate regions.

Range

Found in Cuba.

Clay-Coloured Weevil

The Clay-coloured Weevil, Otiorhynchus singularis, is a small flightless beetle in the family Curculionidae native to Europe and widely established as an introduced pest in many parts of North America and other temperate regions. The adult weevil is typically 5–7 mm in length, mottled gray-brown or clay-colored with patches of pale scales that provide camouflage against bark and soil. Like other Otiorhynchus weevils, the Clay-coloured Weevil is parthenogenetic in most introduced populations, consisting entirely of females that reproduce without mating. Adults are nocturnal, feeding on the foliage and bark of a wide range of host plants including strawberries, raspberries, currants, ornamental shrubs, and nursery stock. The larvae develop in soil, feeding on roots and causing significant damage that can girdle and kill established plants. The species is considered a serious horticultural pest in affected regions, causing economic losses in soft fruit production, nurseries, and ornamental plantings. Management typically involves biological control using entomopathogenic nematodes or fungi, as chemical control of soil-dwelling larvae is difficult. The species is well established across temperate Europe and has been accidentally introduced to parts of North America through the horticultural trade.

Coastal Ragweed

Coastal ragweed (Ambrosia hispida) is a perennial herb in the family Asteraceae, native to the coastal dunes, sandy beaches, and cays of Cuba, the Bahamas, and the wider Caribbean region. It grows in pioneer beach and dune vegetation, often forming spreading colonies that help stabilise loose coastal sands. Like other members of the genus Ambrosia, it bears inconspicuous greenish-white flowers arranged in racemes; male flower heads produce wind-dispersed pollen that can trigger allergic rhinitis in sensitive individuals. The deeply lobed, hispid leaves are adapted to reflect intense solar radiation and tolerate salt spray. Coastal ragweed plays an ecological role in early dune succession, binding sand and enabling other plant species to establish. The genus is widespread globally, with several Ambrosia species considered noxious weeds in agricultural settings, though Ambrosia hispida is restricted to its native Caribbean coastal range. The IUCN assesses it as Least Concern, reflecting adequate population size across its Caribbean coastal distribution. Pressure from coastal development and tourism infrastructure poses a localised threat to dune communities it inhabits.