Spinneret
A spinneret is a
Most spinnerets are not simple structures with a single orifice producing a single thread, but complex structures of many microscopic spigots, each producing one filament. This produces the necessary orientation of the protein molecules, without which the silk would be weak and useless. Spigots can be singular or found in groups, which also permits spiders to combine multiple filaments in different ways to produce many kinds of silk for various purposes. Spinneret morphology can help arachnologists identify the taxon of a specimen and the specific morphology of a spigot can determine its use as well. For example, flagelliform spigot is unique to Araneoidea, and another kind of spigot found in sets of three, referred to as cylindrical gland spots, are found only in females and used for making egg sacs.[5] The desert grass spider, Agelenopsis aperta, has especially prominent spinnerets that extend out of the end of their abdomen.[6]
Various species of spiders use silk extruded from spinnerets to build webs, to transfer sperm, to entrap insects by wrapping it around them, to make egg-cases, to manipulate static electricity in the air, and to fly (ballooning), etc.
Some insect larvae (including
Evolution
Observations suggesting that there might be silk-producing organs on the feet of the zebra tarantula (Aphonopelma seemanni) led to questions about the origins of spinnerets. It was hypothesised that spinnerets in spiders were originally used as climbing aids on the feet and evolved and were used for webmaking at a later time.[8]
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The compact spinnerets of Argiope bruennichi; placed ventrally below the posterior.
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A barn spider encases her prey in silk emanating from her spinneret seen in the foreground.
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Ventral aspect of spinnerets of spider species with unusually long spinnerets.
References
- ^ INSECTA: EMBIOPTERA (EMBIIDINA) Archived 2013-12-03 at the Wayback Machine, Retrieved December 1, 2013
- ^ Wiggins, Charlotte (Nov 10, 2013). "Gardening to Distraction: Along came a spider". The Rolla Daily News. Therolladailynews.com. Retrieved December 1, 2013.
- PMID 20696272.
- ^ Spider Identification – Types of Spiders, Retrieved December 1, 2013
- JSTOR 3705406. Retrieved 31 August 2020.
- ISBN 978-0-520-27488-4, retrieved 2020-12-08
- ISBN 0-412-61390-5.
- S2CID 4415648.
External links