Cesonia

Simon, 1893

Species Guides

8

Cesonia is a of ground spiders in the Gnaphosidae, first described by Eugène Simon in 1893. The genus contains 31 distributed across North America, the Caribbean, and parts of the Mediterranean. Despite their as "ground spiders," many species are frequently found on vegetation and in arboreal . Cesonia bilineata, the type species, has been documented engaging in on spiderlings of other spider species.

Cesonia rothi by (c) Jason Eckberg, some rights reserved (CC BY), uploaded by Jason Eckberg. Used under a CC-BY license.Cesonia by (c) Jake Nitta, some rights reserved (CC BY), uploaded by Jake Nitta. Used under a CC-BY license.Common Spiders U.S. 012-3 by James Henry Emerton (1847 – 1931). Used under a Public domain license.

Pronunciation

How to pronounce Cesonia: //sɛˈsoʊ.ni.ə//

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Members of Cesonia can be distinguished from other ground spiders by their characteristic body proportions and arrangement typical of Gnaphosidae. Cesonia bilineata, the most studied , has a body length of 4.3–7.0 mm in females—substantially smaller than many sympatric spiders such as Pisaurina mira (12.5–16.5 mm). The lacks the prominent seen in some other gnaphosid genera. Species identification requires examination of genitalic structures and often geographic provenance.

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Habitat

Wooded , forest edges, and shrubbery. Many are arboreal rather than strictly ground-dwelling, frequently found on foliage, twigs, and walls. Cesonia bilineata occurs in wooded habitats from New England to the Florida panhandle and west to Nebraska.

Distribution

North America (eastern United States, southern Canada, Mexico, southwestern United States), Caribbean (Cuba, Jamaica, Hispaniola, Puerto Rico, Virgin Islands, Panama, St. Vincent, Dominica, St. Kitts and Nevis), and Mediterranean region (Greece, Crete, Turkey).

Diet

Cesonia bilineata preys on other spiders, including spiderlings of Pisaurina mira and Peucetia viridans. The attacks victims from behind. Specific prey for other Cesonia species is not documented.

Behavior

Highly agile climbers, frequently observed on vegetation rather than ground surfaces. Cesonia bilineata has been observed entering nursery webs of other spider to prey on guarded spiderlings.

Ecological Role

, including intraguild on other spiders.

Similar Taxa

  • Other GnaphosidaeGround spiders share general body plan and arrangement; Cesonia distinguished by specific genitalic and preferences.
  • Pisaurina miraSympatric and larger nursery web spider; Cesonia bilineata has been documented preying on its spiderlings, but are easily distinguished by size (C. bilineata females 4.3–7.0 mm vs. P. mira females 12.5–16.5 mm) and leg proportions.

Misconceptions

The "ground spider" is misleading for many Cesonia , which are more frequently encountered on vegetation and walls than on soil surfaces.

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Sources and further reading