Posts Tagged ‘spider’

The silk spiders produce is tougher than Kevlar and more flexible than nylon, and Air Force researchers think it could it could be key to creating new materials that take the load and heat off troops in the field.

Scientists at the Air Force Research Lab and Purdue University have been examining natural silk to get a sense of its ability to regulate temperature — silk can drop 10 to 15 degrees Fahrenheit through passive radiative cooling, which means radiating more heat than it absorbs, according to an Air Force news release.

Those researchers want to apply that property to synthetics, like artificial spider silk, which is stronger than Kevlar, the polymer typically used in body armor, and more flexible than nylon.

Enhancing body armor and adding comfort for troops is one of many improvements hoped for by a team led by Dr. Augustine Urbas, a researcher in the Functional Materials Division of the Materials and Manufacturing Directorate.

“Understanding natural silk will enable us to engineer multifunctional fibers with exponential possibilities. The ultra-strong fibers outperform the mechanical characteristics of many synthetic materials as well as steel,” Urbas said in the release. “These materials could be the future in comfort and strength in body armor and parachute material for the warfighter.”

In addition to making flexible, cooler body armor, the material could also be used to make tents that keep occupants cooler as well as parachutes that can carry heavier loads.

Artificial spider silk may initially cost double what Kevlar does, but its light weight, strength, flexibility, and potential for other uses make it more appealing, according to the release.

Air Force researchers are also looking at Fibroin, a silk protein produced by silkworms, to create materials that can reflect, absorb, focus, or split light under different circumstances.

It’s not the military’s first attempt to shake up its body armor with natural or synthetic substances.

Two years ago, the Army said it was looking into using genetically modified silkworms to create a tough, elastic fiber known as Dragon Silk.

Dr. James Zheng, chief scientist for project manager Soldier Protection and Individual Equipment, told Army Times at the time that while the Army is developing and testing material solutions all the time, “Mother Nature has created and optimized many extraordinary materials.”

At the end of 2016, then-Air Force Academy cadet Hayley Weir and her adviser, professor Ryan Burke, successfully tested a kind of viscous substance that could be used to enhance existing body armor. Weir did not reveal the formula for the substance, but she used plastic utensils and a KitchenAid mixer to whip up the gravy-like goo, placing it in vacuum-sealed bags and flattened into quarter-inch layers.

The material was designed to be lighter than standard Kevlar and offer more flexibility for the wearer. During tests, when struck by bullets, the gooey material absorbed the impact and stopped the bullets.

https://www.businessinsider.com/military-scientists-want-to-use-spider-silk-for-body-armor-parachutes-2018-8

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By Deepa Padmanaban

A striking new species of crab has been found living in tree-holes high above the ground. The animal, which fits in the palm of a human hand, has a deep bluish black body that stands out against the tree bark that it prowls for worms and seeds to eat.

Scientists discovered the crab—named Kani maranjandu—in the lush forests of the Western Ghats in south India. It’s an entirely new genus and species named after the Kani, the tribal community that noticed the crabs, and maranjandu, the local colloquial term for tree crab.

The forest-dwelling Kani first reported sightings of “long-legged crabs” on trees in 2014. A. Biju Kumar, a professor of aquatic biology at the University of Kerala, was at that time leading a project to survey the Western Ghats of Kerala for freshwater crabs. After months of tracking the tree crabs with the help of the tribesmen, Kumar and his student Smrithy Raj recently managed to catch a couple of these elusive crabs.

In the Journal of Crustacean Biology, the scientists describe Kani maranjandu as having a distinct hard outer shell or carapace that is broad, swollen, and convex. Most conspicuously, the legs are extremely long, with slender, curved, sharp ends that help them get a good grip on the tree, making them effective climbers.

The crabs live in water-filled hollows of tall evergreen and deciduous trees. The Kani tribesmen detect their presence by looking for air bubbles coming out of the hollows. Outside the hollows, the crabs move rapidly on tree trunks, using their pincer-bearing thick front legs to propel themselves.

The crabs are shy creatures, retreating deep inside the hollows when approached. The younger ones take shelter in the canopy of the trees, up to about 30 feet. That’s unusual for crabs, which don’t normally climb more than a few feet into trees.

“This lifestyle of tree living indicates that, since they cannot disperse widely through the sea, their range tends to be limited to a very narrow area,” says Tohru Naruse, an expert on crab biodiversity at Japan’s University of the Ryukyus. He not involved in the discovery.

This geographical restriction could mean that any impact on their habitat could put the species at greater risk.

Biju Kumar also stresses the importance of the crab’s habitat: the large trees and forest ecosystem of the Western Ghats. The crabs’ existence hinges on rainwater collected in tree hollows, and the crabs have been observed to change trees if the hollows dry up. The broad, swollen carapace is an adaptation that helps them hold water in their gill chambers.

“It also suggests that the tree-climbing behavior and morphology of Kani maranjandu, and possibly other related, undiscovered species, has evolved where they are distributed,” adds Naruse.

For Peter K.L. Ng, a National University of Singapore biologist who helped classify Kani maranjandu, the species’ most alluring feature is how it illustrates crab evolution. “The exciting thing for me is that these crabs, regardless of where they have been found, and how they are related (or unrelated) to each other, they have nevertheless evolved to use specialized habitats to enhance their survival—in this case, tree-holes and climbing,” he says.

http://news.nationalgeographic.com/2017/04/new-crab-species-india-weird-wild-animals/

Dwarf spiders don’t need to take paternity tests to know who the father is—for the most part. Right after copulation, males plug up the genital tract of females (red box in picture) to ensure that competitors can’t deposit sperm. Researchers studying the technique found that the larger the plug, the more difficult it is for subsequent males to remove. Described this month in Behavioral Ecology and Sociobiology, the “stoppers” effectively prevent 67.5% of males who show up later from breeding.

Thanks to Dr. Rajadhyaksha for bringing this to the attention of the It’s Interesting community.

http://news.sciencemag.org/sifter/2014/06/how-male-spiders-keep-females-to-themselves