Orb-web spider

My fascination with people s DMT visions leads me to discuss DMT realities in great detail throughout this book. I also dwell on Marcel Proust and Albert Einstein, perhaps the ultimate expressors of creativity in literature and science. Just as termites are designed to make intricate mounds. Golden Orb Web spiders to weave tremendous webs, and bower birds to construct ornate nests decorated with colorful baubles including... 

Enders, F. (1975). Airborne pheromone probable in orb web spider Argiope aurantia (Araneidae). British Arachnological Society News 13 5-6. 

Gaskett, A.C., Herberstein, M.E., Downes, B. and Elgar, M.A. (2004). Changes in male mate choice in a sexually cannibalistic orb-web spider (Araneae Araneidae). Behav., 141,1197-1210. 

Bladdedge, T. A. and Hayashi, C. Y. 2006. Silken toolkits Biomechanics of silk fibers spun by the orb web spider Argiope argentata (Fabricius 1775). J Exp Biol, 209,2452-61. 

Figure 6.3 Illustration of an assembly model and the extracellular transport of spider silk major ampullate (MAA) protein in orb web spiders. (Reprinted with permission from Ref [7], Copyright (2005) Elsevier.)...

Palma MS, Nakajima T (2005) A natural combinatorial chemistry strategy in acylpolyamine toxins from nephUinae orb-web spiders. Toxin Rev 24 209-234... 

Crystallinity. Generally, spider dragline and silkworm cocoon silks are considered semicrystalline materials having amorphous flexible chains reinforced by strong stiff crystals (3). The orb web fibers are composite materials (qv) in the sense that they are composed of crystalline regions immersed in less crystalline regions, which have estimates of 30—50% crystallinity (3,16). Eadier studies by x-ray diffraction analysis indicated 62—65% crystallinity in cocoon silk fibroin from the silkworm, 50—63% in wild-type silkworm cocoons, and lesser amounts in spider silk (17). 

Work, R. W. (1981). A comparative study of the supercontraction of major ampullate silk fibres of orb web building spiders (Araneae)./. Arachnol. 9, 299-308. 

From a defensive point of view, it was shown that sequestered PAs constitute an efficient protection against the orb-weaving spider Nephila clavipes, which liberates butterflies unharmed from its web. In this study, AT-oxides were shown to be more active than the corresponding free bases. This could be correlated with physicochemical properties of these molecules in interaction with the Nephila receptors. Moreover, there was a significant correlation between dosage and antipredator activity of PAs [160]. 

Higgins, L.E., Townley, M. A., Tillinghast, E. K. and Rankin, M. A. (2001). Variation in the chemical composition of orb webs built by the spider Nephila clavipes (Araneae, Tetragnathidae). Journal of Arachnology 29 82-94. 

A spider s orb-web is formed by extrusion of a concentrated protein solution and stretching of the resulting fiber. The cross-strands, which are stronger than steel, resemble silkworm silk. The molecules contain microcrystalline p sheet domains that are rich in Gly-Ala repeats as well as polyalanine segments. The capture spiral is formed from much more elastic molecules that contain many -tum-forming sequences. These assume a springlike p spiral. See Box 2-B. 

Figure 12.4 Percent of prey item (Utetheisa, mealworms) remaining following attack by the orb-weaving spider Nephila davipes. Items were placed into individual webs with forceps (mealworms) or flipped from vials (Utetheisa).

Work, R.W. "Dimensions, birefringences, and force-elongation behavior of major and minor ampullate silk fibers from Orb-Web-Spinning Spiders - Effects of wetting on these properties". Text. Res. ]. 47(10), 650-662 (1977). 

The cocoon silk of the silk worm is an excellent textile material and the commercial activity in this realm attests to that. Its mechanical properties, however, are rather modest. This has been attributed to the fact that superior mechanical characteristics are not required in the cocoon. On the other hand, in spider s orb-web silk, the spider needs a fiber that can absorb the impact of the falling insect prey. Hence, the need for superior mechanical characteristics. 

Take the case of the spider. Four hundred million years ago, spiders used their silk to weave a hiding place. But then insects developed wings and the spider began to develop aerial webs to catch them as food. About one-third of the 35,000 known spider species weave orb webs (the standard kind with spokes and spirals) and another third weave sheet webs, cobwebs, and other types of webs to catch insects. 

Some prey, like mosquitoes, fly very tentatively, with their forelegs out. As soon as they touch a web, they retreat. Spiders have developed orb webs in a concave shape with a spring line running straight back from the hub to winch the web into a cocked position. This web springs out to follow the elusive prey and catch them anyway. 

The wasp larva hatches in a couple of days and makes little holes in the spider s cuticle to suck its blood. Spiders feed on their prey, oblivious to the larva feeding, in turn, on its own blood. For the first week or two, the spider continues to build its orb webs several times a day, but then the wasp larva suddenly takes control of the spider s mind. 

In the middle of the night, the spider goes back and forth up to 40 times on the same few spokes of its web. Normally, the spider waits until dawn to make its usual orb web. It is during daylight that the insects it eats usually fly. 

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