Cribellum
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A cribellum is a kind of comb-like device in certain spiders, used to separate fibers of silk drawn from its spinnerets into many extremely fine fibers, giving it a wooly structure. Those fibers are so small in diameter that prey insects easily become entangled in them, without any glue needed. The spiders then bite them before they can get away.
The presence or absence of a cribellum is used to classify spiders into the cribellate and ecribellate (not cribellate) type. The distinction can be used to study evolutionary relationships. However, there are many families with both cribellate and ecribellate members. The only families containing no cribellate members are those in the Palpimanoidea superfamily, and the Dionycha.
Cribellate spiders belong to the following families:
- Amaurobiidae
- Deinopidae
- Desidae
- Dictynidae
- Eresidae
- Filistatidae
- Hypochilidae
- Oecobiidae
- Stiphidiidae
- Tengellidae
- Uloboridae
References
- Eberhard, William G. and Pereira, Flory. 1993. Ultrastructure of cribellate silk of nine species in eight families and possible taxonomic implications (Araneae: Amaurobiidae, Deinopidae, Desidae, Dictynidae, Filistatidae, Hypochilidae, Stiphidiidae, Tengellidae). Journal of Arachnology 21(3): 161-174. [PDF]
- Huber, B.A. (1994): Spermophore morphology reveals a new synapomorphy of Oecobius and Uroctea (Araneae, Oecobiidae). Journal of Arachnology 22: 73-74. [PDF]
- Griswold, C.E., Coddington, J.A., Platnick, N.I. and Forster, R.R. (1999). Towards a Phylogeny of Entelegyne Spiders (Araneae, Araneomorphae, Entelegynae). Journal of Arachnology 27:53-63. [PDF]
External links
- [The Spider - Web and Silk] (description and pictures)
- [Cribellate silk vs. sticky silk]
- [The Evolution of Web Usage in Spiders]
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