Thistle-herbivore
Guides
Larinus carlinae
Canada thistle bud weevil, thistle bud weevil, Canada thistle stem weevil
A small weevil native to Europe and western Asia introduced to North America as a biological control agent for invasive thistles. Adults emerge in spring and feed on developing thistle buds with their elongated snouts. Females drill into flower buds to deposit eggs; larvae hatch and consume reproductive tissues, destroying seeds and preventing plant reproduction. Populations can reduce target thistle species by 90% or more within a decade of establishment. The species has been observed feeding on native North American thistles, raising conservation concerns for endemic species.