Adranes

LeConte, 1849

ant-loving beetles

Species Guides

4

Adranes is a of obligately myrmecophilous beetles in the rove beetle Staphylinidae. These small beetles are entirely dependent on ants of the genus Lasius, living as within their nests. The six described share extreme morphological adaptations for this lifestyle, including complete eyelessness, reduced mouthparts, and highly modified . They are known from North America, with species distributed across the United States and Pacific coast regions.

Pronunciation

How to pronounce Adranes: /əˈdreɪniːz/

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Identification

Adranes can be distinguished from other ant-loving beetles by their highly modified consisting of only two joints, with the second joint very large and heavy (form varies among ). The combination of complete blindness (lacking ), reduced mouthparts, and the presence of specialized hair patches at the tips of the and base of the abdominal dorsum is diagnostic. These hair patches produce secretions that are actively sought by ants.

Habitat

Strictly confined to nests of ants belonging to the Lasius. The specific microhabitat within nests has not been described in detail.

Distribution

North America. recorded from the United States, with particular concentration on the Pacific coast (A. pacificus, A. taylori). Specific range details for individual species are limited in available sources.

Diet

Dependent upon ants for food; exact food source (whether regurgitations, , or other nest materials) not explicitly documented.

Host Associations

  • Lasius - obligate ants that provide food and protection; beetles produce secretions from specialized hair patches as requital

Behavior

Helpless and completely dependent on ants for survival. Attended carefully by Lasius , which actively seek secretions produced by the beetles. The secretions collect on hair patches located at the tips of the and on the base of the abdominal dorsum, and are highly appreciated by the ants.

Ecological Role

Myrmecophilous ; specific function beyond nest dependency not documented.

Similar Taxa

  • Other ClavigeriniShare myrmecophilous habits and morphological reductions, but differ in antennal structure (Adranes has only two antennal joints with enlarged second joint) and specific associations
  • Other PselaphinaeMost are free-living or associated with different ; lack the extreme morphological specialization and obligate Lasius dependency of Adranes

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