Artificial Meadows And Robot Spiders Reveal Secret Life Of Bees
Many animals learn to avoid being eaten by predators. Now ecologists have discovered that bumblebees can even learn to outwit colour-changing crab spiders
Spider attacking a foraging bumblebee. Bumblebees can even learn to outwit colour-changing crab spiders. (Credit: Image courtesy of Queen Mary, University of London)
Bumblebees learn to avoid camouflaged predators by sacrificing foraging speed for predator detection, according to scientists from Queen Mary, University of London.
One of the bumblebee's main predators is the crab spider. Crab spiders hunt pollinating insects like bees and butterflies by lying in wait on flowers, and are particularly difficult for their prey to spot because they can change their colour to blend in with their surroundings.
Dr Tom Ings and Professor Lars Chittka from Queen Mary's School of Biological and Chemical Sciences wanted to discover whether bumblebees could learn to avoid these crab spiders. Their study, funded by the NERC and published in the journal Current Biology, shows how a run in with a spider affected the bees' foraging patterns.
Dr Ings and his team allowed a colony of bumblebees (Bombus terrestris) to forage in a meadow of artificial flowers in a 'flight arena' which contained 'robotic' crab spiders. Some of the spiders were well hidden, others were highly visible. Whenever a bee landed on a flower which contained a robot spider, the spider 'caught' the bee by trapping it briefly between two foam pincers, before then setting it free to continue foraging.
The team used 3D tracking software to follow the bees' movements, and found that the bees which were caught by a camouflaged spider slowed down their subsequent inspection flights. Although they lost valuable foraging time by slowing down, they were more likely to accurately detect whether there was a hidden crab spider present.
In addition, the bees which had already been caught a few times the day before by the hidden spiders behaved as if they saw spiders where there were none i.e. they rejected foraging opportunities on safe flowers, 'just in case' and were more wary than bees which had been caught by the more conspicuous spiders.
Dr Ings commented: "Surprisingly, our findings suggest that there is no apparent benefit to the spider in being camouflaged, at least in terms of prey capture rates. Spider camouflage didn't increase the chances of a bumblebee being captured, or reduce the rate at which the bees learnt to avoid predators. But our results did show that the bees which encountered camouflaged spiders were worse off in terms of reduced foraging efficiency."
Dr Ings will present his full findings on 3 September 2008 to the British Ecological Society’s Annual Meeting at Imperial College, London.
http://www.sciencedaily.com/releases/20 ... 225431.htm
Superbug Killers: Magnetic-Like Coating Attracts and Kills Bacteria Without Using Traditional Antibiotics
ScienceDaily (May 10, 2012) —The superbugs have met their match. Conceived at Nanyang Technological University (NTU), it comes in the form of a coating which has a magnetic-like feature that attracts bacteria and kills them without the need for antibiotics.
MRSA in contact with coated contact lenses. (Credit: Image courtesy of Nanyang Technological University)
The killer coating, which has been shown to destroy 99 per cent of the bacteria and fungi that it comes in contact with, is now being used by two companies: a contact lens manufacturer and a company specializing in animal care products.
The next step is to extend its use in a wide range of biomedical and consumer products, ranging from implants and surgical instruments to kitchen utensils and cutlery, as appears to be harmless to human cells.
This is an alternative solution which could replace traditional antibiotics -- currently the main defense against bacteria -- now powerless against super bugs.
The brainchild of Professor Mary Chan, Acting Chair of NTU's School of Chemical and Biomedical Engineering, the coating made from Dimethyldecylammonium Chitosan methacrylate has earned a place in the journal Nature Materials.
This "sponge-like" polymer holds a positive charge, which acts as a magnet-type of force to draw in bacteria which has a negative charge on their cell walls. When the bacterium comes in contact with the coating, the cell walls are 'sucked' into the nanopores, causing the cell to rupture, thus killing the bacterium.
"The coating can also be applied on biomedical objects, such as catheters and implants to prevent bacterial infections, which is a serious cause of concern as many bacteria are now developing resistance to antibiotics -- currently our main source of treatment for infections," Prof Chan said.
"By developing novel materials which uses physical interaction to kill bacteria cells, we envisage this can be an alternative form of treatment for bacterial infections in the near future."
Superbugs which had fallen prey to the coating include Pseudomonas aeruginosa, which can cause infections in the upper respiratory tract, gastrointestinal tract and the urinary tract; and Staphylococcus aureus, which can cause infections ranging from skin boils or abscesses to deadly diseases such as pneumonia and meningitis.
This research for a broad-spectrum antimicrobial coating was first sparked off by Prof Chan wanting to find an effective way to combat bacteria and fungi on contact lenses which could cause corneal infections (microbial keratitis) that could lead to permanent visual damage.
According to a 2006 study, the estimated annual incidence of a common fungi corneal infection, Fusarium keratitis, related to contact lens wear in Singapore is 2.35 per 10,000 wearers.
Building on the success of the antibacterial coating, Prof Chan and her doctoral student, Mr Li Peng, have now succeeded in making another broad-spectrum antimicrobial solution of a similar kind which is highly selective, killing off only bacteria and fungi without harming human cells In vitro.
Their research was published recently in the journal, Advanced Materials. This liquid material based on cationic antimicrobial peptidopolysaccharide, isa polymer which is attracted to microbial cell walls. When the two come into contact, the integrity of the cell wall is disrupted which leads to its rupture and death.
As this novel material kills cells via the destruction of cell walls, it makes it extremely difficult for bacteria to develop an effective resistance.
Prof Chan hopes to further develop this solution into topical applications such as cream and lotions, which can be used to disinfect and treat serious or chronic wounds such as lesions suffered by diabetic patients, killing any bacteria present that are resistant to antibiotics.
"Our long term goal is to develop this into an ingestible form, so it can effectively treat bacterial infections within the body, such as pneumonia and meningitis, replacing antibiotics as the standard treatment." she added.
The two antimicrobial prototypes -- the coating and the liquid solution -- took a total of five years to research and costs over $800,000 to develop.
Prof Chan now aims to improve the liquid solution by developing it into a safe and proven antibiotic replacement within the next five years as the demand for such alternatives will be even higher with the rapid emergence of superbugs.
http://www.sciencedaily.com/releases/20 ... 095940.htm
Regenerative Medicine: Could the Ways Animals Regenerate Hair and Feathers Help Restore Human Fingers and Toes?
ScienceDaily (May 10, 2012) —The latest issue of the journal Physiology contains a review article that looks at possible routes that unlock cellular regeneration in general, and the principles by which hair and feathers regenerate themselves in particular.
The authors apply what is currently known about regenerative biology to the emerging field of regenerative medicine, which is being transformed from fantasy to reality.
While the concept of regenerative medicine is relatively new, animals are well known to remake their hair and feathers regularly by normal regenerative physiological processes. In their review, the authors focus on (1) how extrafollicular environments can regulate hair and feather stem cell activities and (2) how different configurations of stem cells can shape organ forms in different body regions to fulfill changing physiological needs.
The review outlines previous research on the role of normal regeneration of hair and feathers throughout the lifespan of various birds and mammals. The researchers include what is currently known about the mechanism behind this re-growth, as well as what gaps still exist in the knowledge base and remain ripe for future research.
The review examines dozens of papers on normal "physiological regeneration" -- the re-growth that happens over the course of an animal's life and not in response to an injury. This regeneration takes place to accommodate different stages in an animal's life (e.g., replacing downy chick feathers with an adult chicken's, or replacing the fine facial hair of a young boy with the budding beard of an adolescent), or in response to various environmental conditions (e.g., cats shedding a thick winter coat in the summer heat but re-growing it when the seasons change again, or snowshoe hares switching from brown in the summer to white in the winter for camouflage).
These changes seem to respond both to internal cues such as physiology of the hair follicle itself, or external cues such as the environment, but the mechanisms behind these normal alterations are largely unknown. Stem cells inside the follicle prompt hair and feather regeneration, but researchers are still unsure how to guide those cells to form the shape, size, and orientation of these "skin appendages" so that controlled re-growth is possible. Additionally, scientists are still unsure how to re-grow hair on skin in people after severe injuries that lead to scar tissue.
Importance of the Findings
The reviewed studies suggest that while researchers are making headway in understanding how and why hair and feathers regenerate after normal loss or in response to different life stages, much still remains unknown. This missing knowledge could hold valuable clues to learning how to regenerate much more complicated and valuable structures after loss to injury, such as fingers and toes.
"Using the episodic regeneration of skin appendages as a clear readout, we have the opportunity to understand and modulate the behavior or adult stem cells and organ regeneration at a level heretofore unknown," the authors say.
http://www.sciencedaily.com/releases/20 ... 113859.htm
The young star LL Ori forms a bow shock as it moves through the Orion Nebula.
Andrew Fazekas---for National Geographic News
Published May 10, 2012
The sun is moving through the Milky Way slower than previously thought, according to new data from a NASA spacecraft.
From its orbit around Earth, the Interstellar Boundary Explorer (IBEX) satellite measured the speeds of interstellar particles entering at the fringes of our solar system, 9 billion miles (14.5 billion kilometers) from the sun.
(Related: "'Alien' Particles Found Invading Our Solar System—A First.")
Plugging the new data into computer models, the IBEX team calculates that the sun is moving at about 52,000 miles (83,700 kilometers) an hour—about 7,000 miles (11,000 kilometers) slower than thought.
The discovery suggests that the protective boundary separating our solar system from the rest of the galaxy is missing a bow shock, a major structural component thought to control the influx of high-energy cosmic rays.
(See "New Hubble Videos Show Star Jets in Action.")
The sun is constantly sending out charged particles in all directions, forming a cocoon around the solar system called the heliosphere.
Like a boat moving through water, it's long been thought that the "bow" of the heliosphere forms a crescent-shaped shockwave as our solar system plows through the surrounding cloud of interstellar gas. (See "Solar System's 'Nose' Found; Aimed at Constellation Scorpius.")
But the new IBEX findings mean the sun is moving so slow that pressure from material flowing around the heliosphere is 25 percent lower than expected—not enough for a bow shock.
Until now, "all the solar system models and theories included a bow shock," said study leader David McComas of the Southwest Research Institute in San Antonio, Texas.
"Having learned for nearly three decades about it, I was literally shocked when we found it was missing."
Cosmic-Ray Shielding Key for Life?
The absence of a bow shock is significant, McComas said, because it may indicate that the heliosphere is actually more robust than thought.
With less pressure from outside material, the boundary region isn't being compressed and therefore weakened as much as expected, which means it should better repel cosmic rays.
(Related: "Solar System 'Force Field' Shrinks Fast.")
And understanding exactly how the heliosphere acts as a gatekeeper for cosmic rays could help scientists evaluate the chances for life on other worlds.
According to McComas, some researchers believe that the cosmic rays that do get through the heliosphere can impact Earth's climate, because the high-energy particles can ionize—or electrically charge—matter in the atmosphere, leading to heightened cloud formation and lightning generation.
Other experts think the particles could even be related to bursts of evolution or extinction in our planet's history, because the radiation can influence DNA patterns.
(Also see "Ancient Mass Extinctions Caused by Cosmic Radiation, Scientists Say.")
For now, the science behind how cosmic rays have influenced Earth is quite controversial, said Seth Redfield, an astronomer from Wesleyan University in Connecticut who was not involved with the new IBEX study.
Still, considering the rays' expected effects, Redfield said, "it seems obvious to me that there will be scenarios or times when the cosmic-ray flux on a planet is important and [is] having a major influence on the evolution of the planetary atmosphere or even on biological processes on its surface."
In that case, astronomers assessing the habitability of alien planets may need to start considering not only the chances for liquid water but also the strength of other stars' protective cocoons, study leader McComas said.
"There is no doubt," he said, "that questions about cosmic-ray shielding go right to the heart of some really important questions related to life as we know it."
Sun Is Moving Slower Than Thought
"The Heaven's Lights are fed by the energy generated inside the furnaces of Hell; I AM One Conductive Wire! "
----by Michael Balter on 14 May 2012
Since their discovery in 1994, the spectacular paintings of lions, rhinos, and other animals in southern France's Chauvet Cave have stood out as the oldest known cave art, clocking in at about 37,000 years old.* But there have been occasional sightings of other cave art that is equally ancient, although its dating has been more uncertain. Now a team working at another site in the south of France claims to have discovered what appear to be engravings of female genitalia that are as old as or older than Chauvet, possibly making them the world's most ancient cave art.
Eye of the beholder? An engraving of what might be female genitalia (inset) from France's Abri Castanet clocks in at 37,000 years, at least as old as the famous Chauvet Cave.
Homo sapiens first colonized Europe from Africa around 40,000 years ago. But until the early 1990s, there was little firm evidence that our species engaged in sophisticated artistic activity that early. Many archaeologists assumed that modern humans developed their artistic skills only gradually, culminating in spectacular galleries like the 15,000-year-old painted caves at Lascaux in France and Altamira in Spain. The discovery of Chauvet changed all that and convinced most researchers that early artists had brought their skills with them from Africa.
Yet for years Chauvet seemed to stand alone, leading some archaeologists to question whether its dating—based in large part on radiocarbon samples taken directly from its charcoal paintings—was correct. Nevertheless, evidence for other art of about the same age continued to accumulate. At Fumane Cave in Italy, for example, archaeologists found depictions of animals and what appeared to be a half-human, half-beast figure, dated to about 37,000 years ago or even older, although the error ranges for the dates were fairly wide.
Since 1994, the year of Chauvet's discovery, a team led by archaeologist Randall White of New York University in New York City has been working at the Abri Castanet, a rock shelter (a shallow cave usually at the base of a cliff) in southern France's Vezere valley. Originally excavated in the early 20th century, the Abri Castanet has long been considered one of the earliest modern human sites in Europe, with occupation layers dated back to nearly 40,000 years ago. White's excavations have uncovered considerable evidence of symbolic and artistic activity at the site, including hundreds of pierced snail shells apparently used as ornaments and three limestone blocks adorned with engravings, including one the team interprets as a vulva. But the blocks, which came from the shelter's collapsed roof, were impossible to date because they do not contain the kind of organic matter necessary for radiocarbon analysis.
In 2007, however, the team began excavating another large block that had fallen from the roof and directly onto a segment of the cave floor once occupied by prehistoric humans. As White and his colleagues broke the stone slab into sections and lifted them out, they discovered that the underside had been engraved with another vulva-like image (see photo). When they sent the bones of reindeer and other animals from the cave floor to the University of Oxford's radiocarbon dating lab for analysis, the dates clustered tightly between 36,000 and 37,000 years ago. And because there was no accumulation of sediments or other deposits between the archaeological layer and the stone slab, the team argues that the painted cave ceiling must be at least as old as the bones.
That would mean that the artworks at Abri Castanet are also at least as old as those at Chauvet, White and co-workers conclude in a paper published online today in the Proceedings of the National Academy of Sciences. Because these images of vulvas are very different from the charcoal and ochre drawings at Chauvet, the team thinks that regional differences in artistic traditions were already established in Europe by that time, even at sites like Chauvet and Abri Castanet that are only a few hundred kilometers apart.
One key difference, White says, is that whereas the paintings at Chauvet are hidden deep within that cave and away from living areas, the depictions at Abri Castanet were on the rock shelter ceiling right above the spaces where prehistoric humans slept and ate, making them a kind of everyday and public art.
Harold Dibble, an archaeologist at the University of Pennsylvania, says the team's dating of the vulva engraving appears sound because it cannot be any younger than the surface onto which it fell and might even be older. "The context of the find is quite clear," Dibble says. As for the long-standing tradition among archaeologists working in France of interpreting such images as vulvas, Dibble says, "Who the hell knows" what they really represent? Dibble adds that such interpretations could be colored by the worldview of Western archaeologists whose culture probably differs greatly from that of prehistoric peoples. "Maybe it's telling us more about the people making those interpretations" than the artists who created the images, Dibble says. On the other hand, he says, the repeated use of this image at other sites in the Vezere valley suggests that it was some sort of "shared iconography" that might identify specific groups of people. Indeed, archaeologists have also identified differences in the styles of personal ornaments and other artifacts that might also reflect different groups or tribes, much as people express their group identities by the way they dress today.
Paul Pettit, an archaeologist at the University of Sheffield in the United Kingdom, agrees that the new work "provides admirable independent verification of the age of the Castanet rock art that has been suspected for decades." What's more, argues Pettit, a leader of a small but vocal group of archaeologists who have questioned the dating of the Chauvet paintings, the discovery at Abri Castanet helps make their case that the Chauvet art is too sophisticated to be 37,000 years old. "The only other examples of convincingly dated rock art in this period are the painted block from Fumane, which in terms of technical achievement is similar to the Castanet examples," he says. The reason there are so many stylistic differences between the spectacular Chauvet paintings and the relatively simple engravings at Abri Castanet, he insists, is that the Chauvet images are much younger.
*All radiocarbon dates in this story are calibrated to account for differences in the amount of carbon dioxide in Earth's atmosphere between prehistoric times and today.
"The Heaven's Lights are fed by the energy generated inside the furnaces of Hell; I AM One Conductive Wire! "
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