Araneae Clerck, 1757

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Lifespan/Longevity:

Most spider species live a year or less, but some large ones can live for several years. Usually males die soon after they mate, it's only the females that can live longer.

Licensehttp://creativecommons.org/licenses/by-nc-sa/3.0/
Rights holder/Author©1995-2012, The Regents of the University of Michigan and its licensors
Sourcehttp://www.biokids.umich.edu/critters/Araneae/

Reproduction:

Mating System: monogamous ; polyandrous ; polygynous

After mating adult female spiders lay dozens to hundreds of eggs. The number varies among species and is affected by how well fed she is.

Breeding season: Spring to Fall, depending on the species and location.

Key Reproductive Features: semelparous ; iteroparous ; seasonal breeding ; sexual ; fertilization (Internal ); oviparous ; sperm-storing

Female spiders often guard their eggs and young, or even carry them with them until the young have hatched and molted.

Parental Investment: no parental involvement; female parental care

Licensehttp://creativecommons.org/licenses/by-nc-sa/3.0/
Rights holder/Author©1995-2012, The Regents of the University of Michigan and its licensors
Sourcehttp://www.biokids.umich.edu/critters/Araneae/

Functional adaptation:

Web absorbs impacts: spiders
 

Webs of araneid spiders absorb impacts via microscopic engineering.

 

 
  This strategy inspired the web furniture system sketched by Linda Dong, a sophomore industrial design student at Carnegie Mellon University. "How can we create furniture using the least amount of material and manufacturing? The web is inspired by the strong and lightweight nature of spider webs. Using only tension from string, these pieces can hold their structure easily without additional glue or fasteners." Her sketch won the AskNature Student Design Sketch Competition on the basis of clear rendering, attention to product lifecycle and sustainability, and inspiration from nature (see Gallery).

"Spiders provide their nets with many microscopic engineering inventions to prepare the structure for the impact force of their prey or other intruders; webs of araneid spiders have several structural devices designed to absorb the impact energy without breaking the entire structure." (Pallasmaa 1995:81)

  Learn more about this functional adaptation.

  • Pallasmaa, J. 1995. Animal architecture. Helsinki: Museum of Finnish Architecture. 126 p.
Licensehttp://creativecommons.org/licenses/by-nc/3.0/
Rights holder/Author(c) 2008-2009 The Biomimicry Institute
Sourcehttp://www.asknature.org/strategy/eb35ed12a8390522af70c7d5278763a0

Physical Description:

All spiders have two body sections: the cephalothorax in front and an abdomen behind. The abdomen contains the digestive and reproductive systems, and on the underside of it are the glands where silk is produced. The structures that produce the silk are called spinnerets.

They have eight legs, all attached to the cephalothorax. On the front of the cephalothorax are the mouth, the fangs, the eyes, and two small "mini-legs" called pedipalps. These are used to grab prey, and in mating, and are much bigger in male spiders than in females. Different species of spiders have six or eight eyes, and the size and arrangement of eyes is different in different groups. All spiders have fangs that they use to bite their prey with, and most have venom glands.

Female spiders are often much bigger than males.

Other Physical Features: bilateral symmetry

Sexual Dimorphism: female larger

Licensehttp://creativecommons.org/licenses/by-nc-sa/3.0/
Rights holder/Author©1995-2012, The Regents of the University of Michigan and its licensors
Sourcehttp://www.biokids.umich.edu/critters/Araneae/

Functional adaptation:

Silk used for various functions: spiders
 

Individual spiders are able to use silk for a variety of tasks by varying the properties of the silks they produce.

 

 

 

 

 
  "Certainly the most extraordinary material among those tabulated here is spider silk (that of silkworm moths is substantially less extreme)--it has the greatest tensile strength, astonishing extensibility, and by far the greatest strain energy storage…silks vary considerably in their properties, quite clearly tuned by natural selection to their particular tasks…A single araneid spider makes frame silk for the main members of its orb, viscid silk for the spiral threads that catch prey, cocoon silk, prey-wrapping silk, and so forth. Other kinds of spiders make other kinds of silks for other tasks…Spider silks do have an unusual combination of properties. But I know of no evidence that these can be achieved (if one wants them) only by a sequence-specific heteropolymer of amino acids, something unlikely to lend itself to cheap manufacture." (Vogel 2003:344-345)

Watch Video
  Learn more about this functional adaptation.

  • Steven Vogel. 2003. Comparative Biomechanics: Life's Physical World. Princeton: Princeton University Press. 580 p.
Licensehttp://creativecommons.org/licenses/by-nc/3.0/
Rights holder/Author(c) 2008-2009 The Biomimicry Institute
Sourcehttp://www.asknature.org/strategy/888cff76d4915335776aa833733e4c63

AraneaeArachnidaArthropodaAnimalia

Araneae

LicensePublic Domain
Rights holder/AuthorNo known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
Sourcehttp://treatment.plazi.org/id/5F5C6C7C67B0D59FE69F2506366E223D

Functional adaptation:

Silk assembled on demand: spiders
 

Structural components of spider silk are safely stored and assembled on demand with help from a molecular switch.

 

 

 

 
  "Five times the tensile strength of steel and triple that of the  currently best synthetic fibers: Spider silk is a fascinating material…How do spiders form long, highly stable and elastic fibers from the  spider silk proteins stored in the silk gland within split seconds?…
 

"Spider silk consists of protein molecules, long chains comprising  thousands of amino-acid elements. X-ray structure analyses show that the  finished fiber has areas in which several protein chains are  interlinked via stable physical connections. These connections provide  the high stability. Between these connections are unlinked areas that  give the fibers their great elasticity.

 

"The situation within the silk gland is, however, very different: The  silk proteins are stored in high concentrations in an aqueous  environment, awaiting deployment. The areas responsible for interlinking  may not approach each other too closely; otherwise the proteins would  clump up instantaneously. Hence, these molecules must have some kind of  special storage configuration…

 

"The protein chains are  stored with the polar areas on the outside and the hydrophobic parts of  the chain on the inside, ensuring good solubility in the aqueous  environment.

 

"When the protected proteins enter the spinning duct, they encounter  an environment with an entirely different salt concentration and  composition. This renders two salt bridges of the control domain  unstable, and the chain can unfold. Furthermore, the flow in the narrow  spinning duct results in strong shear forces. The long protein chains  are aligned in parallel, thus placing the areas responsible for  interlinking side by side. The stable spider silk fiber is formed.

 "'Our results have shown that the molecular switch we discovered at  the C-terminal end of the protein chain is decisive, both for safe  storage and for the fiber formation process,' says Franz Hagn." (Science Daily 2010)

  Learn more about this functional adaptation.

  • Hagn F; Eisoldt L; Hardy JG; Vendrely C; Coles M; Scheibel T; Kessler H. 2010. A conserved spider silk domain acts as a molecular switch that controls fibre assembly. Nature. 465: 239-242.
  • Rammensee S; Slotta U; Scheibel T; Bausch AR. 2008. Assembly mechanism of recombinant spider silk proteins. PNAS. 105(18): 6590-6595.
  • 2010. Investigating how spiders spin their silk, researchers unravel a key step. Science Daily [Internet],
  • Minkel JR. 2008. Researchers Build Micro Spider-Silk Spinner. Scientific American [Internet],
Licensehttp://creativecommons.org/licenses/by-nc/3.0/
Rights holder/Author(c) 2008-2009 The Biomimicry Institute
Sourcehttp://www.asknature.org/strategy/cf13f604dd36cc0455b232f792c854be

AraneaeArachnidaArthropodaAnimalia

Araneae

LicensePublic Domain
Rights holder/AuthorNo known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
Sourcehttp://treatment.plazi.org/id/BD5B6CF80D1A65A2C6CBDD0E8E8AD6C7

Functional adaptation:

Legs detect airborne vibrations: spiders
 

The legs of some spiders detect airborne vibrations of approaching insects thanks to specialized vibration-sensitive hairs, called trichobothria, on certain leg segments.

 

 

 
  "Spiders can detect vibrations traveling through the air from sources far away. They can do this thanks to specialized vibration-sensitive hairs, called trichobothria, on certain segments of their limbs. These hairs are able to move in any direction, and tell the spider the direction from which an object is approaching and its size. They are so responsive to airborne vibrations that they can deven detect those caused by the wings of insects in flight, alerting the spider to the approach of a potential victim as it heads toward the spider's web." (Shuker 2001:36)
  Learn more about this functional adaptation.

  • Shuker, KPN. 2001. The Hidden Powers of Animals: Uncovering the Secrets of Nature. London: Marshall Editions Ltd. 240 p.
Licensehttp://creativecommons.org/licenses/by-nc/3.0/
Rights holder/Author(c) 2008-2009 The Biomimicry Institute
Sourcehttp://www.asknature.org/strategy/305a60528a6edc16e804fd1bc71233ab

Geographic Range:

Spiders are everywhere! Baby spiders are so light, they can put out a line of silk and float away on a breeze, and so they are spread around the globe. Also, spiders that live in peoples' houses often get moved around by accident when people move. Spiders are found on every continent, and there are over 40,000 species known to science. That's not all of them though, there are thousands more we don't know about yet.

Biogeographic Regions: nearctic (Native ); palearctic (Native ); oriental (Native ); ethiopian (Native ); neotropical (Native ); australian (Native ); oceanic islands (Native )

Licensehttp://creativecommons.org/licenses/by-nc-sa/3.0/
Rights holder/Author©1995-2012, The Regents of the University of Michigan and its licensors
Sourcehttp://www.biokids.umich.edu/critters/Araneae/
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith