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Allegheny Mound Ant - Formica exsectoides
Topic Started: Feb 22 2014, 03:36 PM (4,243 Views)
Taipan
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Allegheny Mound Ant - Formica exsectoides

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Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Genus: Formica
Species: Formica exsectoides

The Allegheny mound ant (Formica exsectoides) is a species of ant native to the Atlantic area of North America. Its range extends from Nova Scotia to parts of Georgia. Like other field ants, the Allegheny mound ant builds large mounds, however this species tends to build some of the largest.

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Aside from the mounds, the ants also act as pests by killing vegetation within 40 to 50 feet (12 to 15 m) of their mounds. The ants inject formic acid into surrounding plants, killing small trees and shrubs. Members of the formic acid producing Formica genus are known for their citrus taste. The Allegheny mound ant's appearance is very striking: both its head and thorax are red-orange; its gaster is black-brown. The ant's colonies are complex. Several different mounds may be interconnected. The tunnels may extend 3 feet (0.91 m) into the ground and 4 feet (1.2 m) upwards in the mound. The mound serves as a solar incubator for the eggs and larvae. Unlike most other ants, Allegheny mound ants have multiple queens. Maturation from egg to adult takes 2.5–3 months. They hunt a wide assortment of arthropods as a protein source and collect aphid honeydew as a source of sugars.
The ants are very aggressive and will bite if a mound is disturbed.

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Ants Are Even Stronger Than You Imagine

Katharine Gammon, ISNS Contributor | February 21, 2014 02:20am ET

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New research finds that ants’ strength lies in their neck joints.

(ISNS) – While the world watches Olympians skate, jump and fly through the air in Sochi, researchers have turned their eyes to a much tinier but equally impressive athlete: the humble field ant.

New research published last month showed that the neck joint of a common field ant can withstand 5,000 times the ant’s weight. Previously, ants had been photographed carrying dead baby birds, so it was estimated they could carry around 1,000 times their weight. But the new numbers surprised even the researchers.

“We guessed that the ants could withstand about 1,000 times their weight, so we figured we’d start there,” said Carlos Castro, a mechanical and aerospace engineer at The Ohio State University in Columbus. “Initially we didn’t think this ant had any extreme capabilities, but they surprised us.”

Testing the ants' strength involved extreme and destructive measures.

Castro and his colleagues anesthetized common field ants and glued their heads to a centrifuge about the size of a compact disc. As the disc spun faster and faster, the forces applied to the ants increased – until their necks deformed, and their heads separated from their bodies at the tiny neck joint.

“We had to put a Plexiglas barrier around the centrifuge to protect the grad students,” said Castro, “because the ant bodies would go flying at the moment of rupture.” The ants’ necks ruptured when the centrifuge applied forces of 3,400 to 5,000 times their average body weight.

In addition to the centrifugal studies, Castro used microcomputed tomography to reconstruct a 3-D model of the ant’s neck joint.

He found that the surface of the ant’s neck had a microstructure of bumps and folds that helped the ants shoulder large loads.

“From a materials standpoint, we found that the properties themselves are similar to other insects,” said Castro. “We think it’s this design rather than material design that helps the ants.”

The full research was published in late January in the Journal of Biomechanics.

Other researchers noted that while ants are certainly strong, the research doesn't necessarily show how much weight than can actually lift and carry.

Karin Moll, a biologist and ant researcher at University College Freiburg in Germany who was not involved in the research, said that the 5,000 mark is impressive, but that it doesn’t necessarily mean that the ants could lift that amount. “The authors showed that the ants can hold that amount, but this situation is different from carrying a load…loads that are actually carried are usually much smaller,” Moll wrote in an email to Inside Science.

Thomas Endlein, a researcher at the University of Glasgow who has studied the sticky pads on ants’ feet, added that lifting large weights is problematic for several reasons -- including the muscle strength, the structural stiffness and balance.

“Muscle strength is often not a problem as smaller animals have relatively more muscle strength to their body weight compared to larger animals,” he wrote in an email to Inside Science. “Still, balancing the weights is a big problem. First, ants have to lever off the weights from the ground which is a tricky business if items are oddly shaped or heavy…then, balancing the item overhead when walking, [it] is also very tricky to avoid falling over.”

Mike Kaspari, a biologist at the University of Oklahoma, said that microbotics – the blending of biology and engineering to build tiny semi-smart animatrons – is one of the most exciting new technologies. “The hope is that these cheap microbots can explore, monitor, and fix our environment, as well as perform other tasks through sheer force of numbers,” he said. “This is another lovely example of how engineers look to the ant to inspire their designs.”

Castro said that the research could be applied to creating robots that could lift and carry more efficiently, taking a nod from the ants’ hybrid soft-hard components. Researchers could also create better composite materials using the combination approach of soft and hard.

He also plans to study more ants from a mechanical point of view by looking at their musculature, and also at ants with different roles within the same species. “We really chose an everyday ant,” he said. “The most optimized ants may be able to withstand forces of 10,000 times their weight.”

http://www.livescience.com/43555-ants-are-even-stronger-than-you-imagine.html




The exoskeletal structure and tensile loading behavior of an ant neck joint

Vienny Nguyen, Blaine Lilly, Carlos Castro
Journal of Biomechanics, Volume 47, Issue 2, 22 January 2014, Pages 497–504
http://dx.doi.org/10.1016/j.jbiomech.2013.10.053

Abstract
Insects have evolved mechanical form and function over millions of years. Ants, in particular, can lift and carry heavy loads relative to their body mass. Loads are lifted with the mouthparts, transferred through the neck joint to the thorax, and distributed over six legs and tarsi (feet) that anchor to the supporting surface. While previous research has explored attachment mechanisms of the tarsi, little is known about the relation between the mechanical function and the structural design and material properties of the ant. This study focuses on the neck – the single joint that withstands the full load capacity. We combine mechanical testing, computed tomography (CT), scanning electron microscopy (SEM), and computational modeling to better understand the mechanical structure–function relation of the neck joint of the ant species Formica exsectoides (Allegheny mound ant). Our mechanical testing results show that the soft tissue forming the neck joint of F. exsectoides exhibits an elastic modulus of 230±140 MPa and can withstand ~5000 times the ant's weight. We developed a 3-dimensional (3D) model of the structural components of the neck joint for simulation of mechanical behavior. Finite element (FE) simulations reveal the neck-to-head transition where the soft membrane material meets the hard exoskeleton as the critical point for failure of the neck joint, which is consistent with our experiments. Our results further indicate that the neck joint structure exhibits anisotropic mechanical behavior with the highest stiffness occurring when the load path is aligned with the axis of the neck.

http://www.sciencedirect.com/science/article/pii/S0021929013005459
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