Trichosirocalus

Colonnelli, 1979

rosette weevils, crown weevils

Species Guides

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A of small true weevils native to the Palearctic region. Several have been widely introduced to North America, Australia, and New Zealand as agents for thistles. The genus was historically treated as containing a single species, T. horridus, but integrative taxonomic studies using molecular and morphological data have revealed multiple distinct species with different associations.

Trichosirocalus horridus by (c) Landcare Research New Zealand Ltd, néhány jog fenntartva (CC BY). Used under a CC-BY license.Trichosirocalus horridus by (c) Roman, néhány jog fenntartva (CC BY), feltöltötte: Roman. Used under a CC-BY license.Trichosirocalus horridus by (c) Landcare Research New Zealand Ltd, néhány jog fenntartva (CC BY). Used under a CC-BY license.

Pronunciation

How to pronounce Trichosirocalus: /ˌtrɪkoʊsɪˈroʊkələs/

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Distribution

Native to the Palearctic region, with records from Europe including France, Germany, Italy, Switzerland, Austria, and Scandinavia (Denmark, Norway, Sweden). Multiple have been introduced to North America (USA, Canada), Australia, and New Zealand for programs.

Human Relevance

Several have been introduced internationally as agents for thistle species (Carduus, Cirsium, and Onopordum). was first released in North America in 1974 for musk thistle control and has become established across multiple continents. Taxonomic confusion regarding species boundaries has complicated tracking of introduced .

Similar Taxa

  • Ceutorhynchus trimaculatusOften studied and released alongside Trichosirocalus for thistle ; both are small ceutorhynchine weevils with similar rosette-feeding habits on Carduus thistles
  • Rhinocyllus conicusAnother introduced weevil for thistle ; Trichosirocalus can be distinguished by their smaller size and preference for rosette-stage plants rather than flowering

Misconceptions

The was long considered (containing only T. horridus). A 2002 taxonomic revision split this into three (T. horridus, T. briesei, T. mortadelo) based on and purported specificity. Subsequent molecular and integrative studies demonstrated that only two species are valid (T. horridus and T. briesei), with T. mortadelo synonymized under T. horridus. This taxonomic instability has caused uncertainty about which species were released in various countries.

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Sources and further reading