Trigonorhinus

Wollaston, T.V., 1861

fungus weevils

Species Guides

8

Trigonorhinus is a of fungus weevils in the Anthribidae, comprising approximately 15-16 described . The genus includes wood-boring species that develop in plant tissues, with at least one species documented as a pest of Caragana liouana in arid regions of China. A notable species, Trigonorhinus sp., has been demonstrated to rely on gut bacterial for production of male essential for mate attraction.

Trigonorhinus griseus by (c) Eric Knight, some rights reserved (CC BY), uploaded by Eric Knight. Used under a CC-BY license.Trigonorhinus limbatus by (c) Rich Sommer, some rights reserved (CC BY), uploaded by Rich Sommer. Used under a CC-BY license.Trigonorhinus by no rights reserved, uploaded by Judy Aschner. Used under a CC0 license.

Pronunciation

How to pronounce Trigonorhinus: /ˌtraɪɡəˈnɔrɪnəs/

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Habitat

Arid regions; associated with woody vegetation. At least one bores into current-year shoots of woody plants, creating galls in plant .

Distribution

Documented from China (Ningxia, Inner Mongolia, Shanxi, Shaanxi provinces); specific collection records from Horinger County, Inner Mongolia. Broader distribution of requires further documentation.

Seasonality

Reproductive activity peaks May–August, synchronized with plant .

Diet

Wood-boring; larvae tunnel into plant and create galls on current-year shoots. Documented : Caragana liouana.

Host Associations

  • Caragana liouana - larval plantlarvae tunnel into plant and create galls on current-year shoots; pest causing branch death by blocking water flow

Life Cycle

Females oviposit on current-year shoots. Larvae tunnel into plant and create galls. Developmental timing synchronized with .

Behavior

Males produce (2,6,10,14-tetramethylheptadecane and heptacosane) that attract females. Pheromone production is mediated by gut bacterial ; depletion reduces pheromone emission by >85% and eliminates female attraction. present in sixth abdominal sternite (elongate in females).

Ecological Role

At least one acts as a pest: galling blocks water flow causing branch death, with potential to harm dryland through plant mortality.

Human Relevance

Documented as an agricultural/forestry pest of Caragana liouana. The demonstrated dependence on gut bacteria for production suggests potential for -targeted pest management strategies.

Similar Taxa

  • other Anthribidae generaTrigonorhinus can be distinguished by -level morphological characters established by Wollaston (1861); specific diagnostic features require examination

More Details

Microbial symbiosis

Trigonorhinus sp. exhibits a decisive dependence on gut bacteria for chemical communication. The single bacterial isolate Acinetobacter guillouiae is sufficient to restore production after depletion, indicating strain-specific control rather than general microbial effect.

Taxonomic uncertainty

-level identification remains ongoing for the well-studied Chinese ; the species has been identified as Trigonorhinus sp. by weevil Boris Korotyaev, with further identification to species level in progress.

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Sources and further reading