Stenus annularis
Erichson, 1840
Stenus annularis is a of rove beetle in the Steninae, described by Erichson in 1840. The Stenus is notable for its members' ability to glide on water surfaces using specialized gland secretions that reduce surface tension. Some species in this genus also employ a unique hunting mechanism involving the ejection of mouthparts using blood pressure to capture small prey. Stenus annularis has a broad distribution across North America, with records from Canada and the United States.
Pronunciation
How to pronounce Stenus annularis: /ˈsteː.nus ˌæn.jʊˈleɪ.rɪs/
These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.
Distribution
Canada (Alberta, British Columbia, Manitoba, New Brunswick, Newfoundland and Labrador, Nova Scotia, Ontario, Quebec, Saskatchewan) and United States (Alabama, Arizona, Colorado, Connecticut, District of Columbia, Delaware, Iowa, Idaho, Illinois, Indiana, Kansas, Kentucky, Massachusetts, Maryland, Maine, Michigan, Missouri, Montana, North Carolina, Nebraska, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, Rhode Island, South Dakota, Texas, Virginia, Vermont, Washington, Wisconsin).
More Details
Taxonomic Status Note
The Catalogue of Life lists Stenus annularis as a synonym, though GBIF and other sources treat it as an accepted . This may reflect ongoing taxonomic revision or regional differences in classification.
Genus Characteristics
While specific traits of Stenus annularis are not well-documented, the Stenus is characterized by: (1) water-gliding ability enabled by pygidial gland secretions that reduce surface tension, allowing beetles to move rapidly across water surfaces; and (2) a specialized predatory mechanism where the is everted using pressure, with paraglossae bearing adhesive secretions to capture small prey such as collembolans. It is not confirmed whether S. annularis possesses both capabilities, as some Stenus lack water-gliding .
Data Limitations
Published literature specifically addressing Stenus annularis appears sparse. Most available information derives from occurrence records and -level studies. The has 20 observations on iNaturalist but lacks a Wikipedia summary or detailed species-level treatment in readily accessible sources.