Spider Web Is Strong and Elastic

black, yellow, and white spider on web during the daytime

Biological Strategy

Eleanor Banwell

Image: Amandad / Pixabay / Free non-commercial use

Capture, Absorb, or Filter Organisms

Many living systems must secure organisms for food. But just as one living system must capture its prey to survive, its prey must escape to survive. This results in capture and avoidance strategies that include trickery, speed, poisons, constructed traps, and more. For example, a carnivorous plant called the pitcher plant has leaves formed into a tube that collect water. Long, slippery hairs within the tube face downward. When insects enter the tube seeking nectar, they lose their footing and slide inside, unable to climb out and escape being eaten and digested by the plant.

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Physically Assemble Structure

Living systems use physical materials to create structures to serve as protection, insulation, and other purposes. These structures can be internal (within or attached to the system itself), such as cell membranes, shells, and fur. They can also be external (detached), such as nests, burrows, cocoons, or webs. Because physical materials are limited and the energy required to gather and create new structures is costly, living systems must use both conservatively. Therefore, they optimize the structures’ size, weight, and density. For example, weaver birds use two types of vegetation to create their nests: strong, a few stiff fibers and numerous thin fibers. Combined, they make a strong, yet flexible, nest. An example of an internal structure is a bird’s bone. The bone is comprised of a mineral matrix assembled to create strong cross-supports and a tubular outer surface filled with air to minimize weight.

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Arachnids

Class Arachnida (“spider”): Spiders, mites, ticks, scorpions

Arachnids get a bad reputation, but they play an important role in the ecosystem by controlling insect populations. Almost half of the species in the class are spiders, and most live in terrestrial environments. Unlike insects, most arachnids have two body sections: the cephalothorax, which is the head and thorax fused together, and the abdomen. Mites and ticks, on the other hand, have only one body section that is relatively flat. This body shape comes in handy for the species that are parasitic, because it makes it harder for their hosts to bite or scratch them off.

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Introduction

In the quiet dawn of the forest, orb weaver spiders craft intricate spiral webs using capture silk, a material as strong as Kevlar and remarkably elastic, enabling it to stretch before snapping back and to withstand the impact of flying insects without breaking or sagging.

The Strategy

Orb weaver capture silk boasts a tensile strength of 1 GPa and can stretch up to 1000% of its original length due to its molecular structure of fibroin proteins, which form pleated beta-sheets stabilized by weak hydrogen bonds that break upon impact and reform once the energy dissipates, allowing the silk to stretch and recover its shape. When an insect crashes into the web, the impact causes these weak hydrogen bonds to break, allowing the silk to stretch without breaking.

The Potential

Inspired by the sacrificial bonds in spider silk, we can develop impact-absorbing, resilient materials for protective gear, architectural designs could incorporate elastic, yet strong, materials inspired by spider silk to create structures that withstand natural forces like earthquakes or high winds, flexing but not breakin, medical applications like sutures and implants that are both durable and flexible, promoting better healing and adaptation within the body, and textiles, creating innovations that are strong, flexible, and resilient.

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Last Updated July 23, 2019

References

Journal article

Molecular nanosprings in spider capture-silk threads

Nature Materials | 01/01/2003 | Becker N, Oroudjev E, Mutz S, Cleveland JP, Hansma PK, Hayashi CY, Makarov DE, Hansma HG

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