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News Article | October 26, 2016
Site: www.newscientist.com

Time to power up the largest radio telescope in the world. China’s Five-hundred-metre Aperture Spherical Telescope, or FAST, began spying on outer space on 25 September. FAST will measure radio waves in space, allowing us to study the rotation of galaxies, monitor the behaviour of pulsars and keep an eye out for signals sent by aliens. It is situated in a remote, mountainous area of Guizhou Province in south-western China, which will help protect it from radio-wave interference, like signals sent by cell phones and Wi-Fi. Construction began in 2011, spurring the relocation of a small village. The telescope will go through a testing and debugging phase before full operation begins, according to the Chinese Academy of Sciences. The telescope, named for the size of its dish – 500 metres across – is about 200 metres wider than its closest rival, the Arecibo Observatory in Puerto Rico, built in the early 1960s. That means that it will be able to see dimmer objects than the Arecibo telescope can detect, says Michael Nolan at the Lunar and Planetary Laboratory at the University of Arizona in Tucson. “Being bigger means it collects more light,” Nolan says. “So if you’re looking at a faint signal, it’ll be brighter in the bigger telescope.” The curved bowl of a radio telescope directs the light it catches into a detection device, usually suspended above the dish. A parabola-shaped disc focuses light into a single point, but can cause distortion as the telescope targets different parts of the sky. Smaller telescopes can move their dishes to observe different regions of space, but FAST is too big to steer. To avoid that problem, FAST’s mirrored panels and its receiver are designed to move in conjunction, allowing scientists to create a parabola-shaped bowl pointed at whatever part of the sky is under observation. “They’re going to have that be a flexible mirror that they can deform to point at the right place,” Nolan says. “Instead of turning it, they’re just going to squash it to be the right shape.” The construction of the telescope shows that observatories like Arecibo aren’t a relic of the past, says Robert Minchin at the Arecibo Observatory. “That they put the money into building FAST is a vote of confidence that telescopes of the Arecibo pattern, these large single-dish telescopes, do have a future,” he says. “As far as we’re concerned, imitation is the greatest form of flattery,” says Christopher Salter, also at the Arecibo Observatory. “It’s very nice to have another sibling very much like ourselves.”


News Article | December 13, 2016
Site: phys.org

Trojan asteroids are travel companions to planets as they orbit the sun, remaining near a stable point 60 degrees in front of or behind the planet. Because they constantly lead or follow in the same orbit, they never will collide with their companion planet. The term "Trojan asteroid" was established when it was decided to name Jupiter's companion asteroids after warriors of the Trojan war in Greek mythology. Six planets in our solar system are known to harbor Trojan asteroids—Jupiter, Neptune, Mars, Venus, Uranus and Earth. Although more than 6,000 Trojan asteroids are known to be orbiting along with Jupiter, scientists have discovered only one Earth Trojan to date: 2010 TK7, found by NASA's NEOWISE project in 2010. Scientists predict that there should be more Trojans orbiting Earth, but these asteroids are difficult to detect because they appear close to the sun from Earth's point of view. In mid-February 2017, however, the OSIRIS-REx spacecraft will be ideally positioned to undertake a survey of the stable point in front of Earth. Over 12 days, the OSIRIS-REx Earth-Trojan asteroid search will employ the spacecraft's MapCam imager to methodically scan the space where Earth Trojans are expected to exist. MapCam is part of the OSIRIS-REx Camera Suite, or OCAMS, which was designed and built by researchers at the UA's Lunar and Planetary Laboratory. Many of the campaign's observations will closely resemble MapCam's planned activities during its upcoming search for small rocks orbiting asteroid Bennu. While the likelihood of finding such small rocks around Bennu is low, the Trojan asteroid search serves as an early rehearsal for this critical safety check, as well as for the mission's primary science operations. "The Earth-Trojan asteroid search provides a substantial advantage to the OSIRIS-REx mission," said Dante Lauretta, OSIRIS-REx principal investigator and professor of planetary science at the Lunar and Planetary Laboratory. "Not only do we have the opportunity to discover new members of an asteroid class, but more importantly, we are practicing critical mission operations in advance of our arrival at Bennu, which ultimately reduces mission risk." The OSIRIS-REx spacecraft is currently on a seven-year journey to rendezvous with, study and return a sample of Bennu to Earth. This sample of a primitive asteroid will help scientists understand the formation of our solar system more than 4.5 billion years ago. Explore further: To Bennu and back


News Article | November 2, 2016
Site: phys.org

Psyche is thought to be the largest metallic asteroid in the solar system, at 300 km (186 miles) across and likely consists of almost pure nickel-iron metal. Scientists had thought Psyche was made up of the leftover core of a protoplanet that was mostly destroyed by impacts billions of years ago, but they may now be rethinking that. "The detection of a 3 micron hydration absorption band on Psyche suggests that this asteroid may not be metallic core, or it could be a metallic core that has been impacted by carbonaceous material over the past 4.5 Gyr," the team said in their paper. While previous observations of Psyche had shown no evidence for water on its surface, new observations with the NASA Infrared Telescope Facility found evidence for volatiles such as water or hydroxyl on the asteroid's surface. Hydroxyl is a free radical consisting of one hydrogen atom bound to one oxygen atom. "We did not expect a metallic asteroid like Psyche to be covered by water and/or hydroxyl," said Vishnu Reddy, from the University of Arizona's Lunar and Planetary Laboratory, a co-author of the new paper about Psyche. "Metal-rich asteroids like Psyche are thought to have formed under dry conditions without the presence of water or hydroxyl, so we were puzzled by our observations at first." Asteroids usually fall into two categories: those rich in silicates, and those rich in carbon and volatiles. Metallic asteroids like Psyche are extremely rare, making it a laboratory to study how planets formed. For now, the source of the water on Psyche remains a mystery. But Redddy and his colleagues propose a few different explanations. One is, again, Psyche may not be as metallic as previously thought. Another option is that the water or hydroxyl could be the product of solar wind interacting with silicate minerals on Psyche's surface, such as what is occurring on the Moon. The most likely explanation, however is that the water seen on Psyche might have been delivered by carbonaceous asteroids that impacted Psyche in the distant past, as is thought to have occurred on early Earth. "Our discovery of carbon and water on an asteroid that isn't supposed to have those compounds supports the notion that these building blocks of life could have been delivered to our Earth early in the history of our solar system," said Reddy. If we're lucky, we won't have to wait too long to find out more about Psyche. A mission to Psyche is on the short list of mission proposals being considered by NASA, with a potential launch as early as 2020. Reddy and team said an orbiting spacecraft could explore this unique asteroid and determine if whether there is water or hydroxyl on the surface. More information: Detection of Water and/or Hydroxyl on Asteroid (16) Psyche. arxiv.org/abs/1610.00802


News Article | November 16, 2016
Site: www.eurekalert.org

Pluto's 'heart' may be cold as ice, but it's in the right place, according to research by University of Arizona scientists Sputnik Planitia, a 1,000-kilometer wide basin within the iconic heart-shaped region observed on Pluto's surface, could be in its present location because accumulation of ice made the dwarf planet roll over, creating cracks and tensions in the crust that point towards the presence of a subsurface ocean. Published in the Nov. 17 issue of Nature, these are the conclusions of research by James Keane, a doctoral student at the University of Arizona's Lunar and Planetary Laboratory, and his adviser, assistant professor Isamu Matsuyama. They propose evidence of frozen nitrogen pileup throwing the entire planet off kilter, much like a spinning top with a wad of gum stuck to it, in a process called true polar wander. "There are two ways to change the spin of a planet," Keane said. "The first--and the one we're all most familiar with--is a change in the planet is a change in the planet's obliquity, where the spin axis of the planet is reorienting with respect to the rest of the solar system. The second way is through true polar wander, where the spin axis remains fixed with respect to the rest of the solar system, but the planet reorients beneath it." Planets like to spin in such a way that minimizes energy. In short, this means that planets like to reorient to place any extra mass closer to the equator, and any mass deficits closer to the pole. For example, if a giant volcano were to grow on Los Angeles, the earth would reorient itself to place L.A. on the equator. To understand polar wander on Pluto, one first has to realize that unlike Earth, whose spin axis is only slightly tilted so that the regions around the equator receive the most sunlight, Pluto is like a spinning top lying on its side. Therefore, the planet's poles get the most sunlight. Depending on the season, it's either one or the other, while Pluto's equatorial regions are extremely cold, all the time. Because Pluto is almost 40 times farther from the sun than we are, it takes the little ball of rock and ice 248 Earth years to complete one of its own years. At Pluto's lower latitudes near the equator, temperatures are almost as cold as minus 400 degrees Fahrenheit, cold enough to turn nitrogen into a frozen solid. Over the course of a Pluto year, nitrogen and other exotic gases condense on the permanently shadowed regions, and eventually, as Pluto goes around the sun, those frozen gases heat up, become gaseous again and re-condense on the other side of the planet, resulting in seasonal "snowfall" on Sputnik Planitia. "Each time Pluto goes around the sun, a bit of nitrogen accumulates in the heart," Keane said. "And once enough ice has piled up, maybe a hundred meters thick, it starts to overwhelm the planet's shape, which dictates the planet's orientation. And if you have an excess of mass in one spot on the planet, it wants to go to the equator. Eventually, over millions of years, it will drag the whole planet over." In a sense, Pluto is a (dwarf) planet whose shape and position in space are controlled by its weather. "I think this idea of a whole planet being dragged around by the cycling of volatiles is not something many people had really thought about before," Keane said. The two researchers used observations made during New Horizons' flyby and combined them with computer models that allowed them to take a surface feature such as Sputnik Planitia, shift it around on the planet's surface and see what that does to the planet's spin axis. And sure enough, in the models, the geographic location of Sputnik Planitia ended up suspiciously close to where one would expect it to be. If Sputnik Planitia were a large positive mass anomaly--perhaps due to loading of nitrogen ice--it would naturally migrate to Pluto's tidal axis with regard to Charon, Pluto's largest moon, as it approaches a minimum energy state, according to Keane and Matsuyama. In other words, the massive accumulation of ice would end up where it causes the least wobble in Pluto's spin axis. This phenomenon of polar wander is something that was discovered with the Earth's moon and with Mars, as well, but in those cases it happened in the distant past, billions of years ago. "On Pluto, those processes are currently active," Keane said. "Its entire geology--glaciers, mountains, valleys--seems to be linked to volatile processes. That's different from most other planets and moons in our solar system." And not only that, the simulations and calculations also predicted that the accumulation of frozen volatiles in Pluto's heart would cause cracks and faults in the planet's surface in the exact same locations where New Horizons saw them. The presence of tectonic faults on Pluto hint at the existence of a subsurface ocean at some point in Pluto's history, Keane explained. "It's like freezing ice cubes," he said. "As the water turns to ice, it expands. On a planetary scale, this process breaks the surface around the planet and creates the faults we see today." The paper is published alongside a report by Francis Nimmo of the University of California Santa Cruz and colleagues, who also consider the implications for Pluto's apparent reorientation. The authors of that paper agree with the idea that tidal forces could explain the current location of Sputnik Planitia, but in order for their model to work, a subsurface ocean would have to be present on Pluto today. Both publications underscore the notion of a surprisingly active Pluto. "Before New Horizons, people usually only thought of volatiles in terms of a thin frost veneer, a surface effect that might change the color, or affect local or regional geology," Keane said. "That the movement of volatiles and shifting ice around a planet could have a dramatic, planet-moving effect is not something anyone would have predicted."


News Article | November 30, 2016
Site: www.eurekalert.org

A team led by UA astronomer Vishnu Reddy has characterized the smallest known asteroid using Earth-based telescopes: Asteroid 2015 TC25 measures just 6 feet across Astronomers have obtained observations of the smallest asteroid ever characterized in detail. At 2 meters (6 feet) in diameter, the tiny space rock is small enough to be straddled by a person in a hypothetical space-themed sequel to the iconic bomb-riding scene in the movie "Dr. Strangelove." Interestingly, the asteroid, named 2015 TC25, is also one of the brightest near-Earth asteroids ever discovered. Using data from four different telescopes, a team of astronomers led by Vishnu Reddy, an assistant professor at the University of Arizona's Lunar and Planetary Laboratory, reports that 2015 TC25 reflects about 60 percent of the sunlight that falls on it. Discovered by the UA's Catalina Sky Survey last October, 2015 TC25 was studied extensively by Earth-based telescopes during a close flyby that saw the micro world sailing past Earth at 128,000 kilometers, a mere third of the distance to the moon. In a paper published in The Astronomical Journal, Reddy argues that new observations from the NASA Infrared Telescope Facility and Arecibo Planetary Radar show that the surface of 2015 TC25 is similar to a rare type of highly reflective meteorite called an aubrite. Aubrites consist of very bright minerals, mostly silicates, that formed in an oxygen-free, basaltic environment at very high temperatures. Only one out of every 1,000 meteorites that fall on Earth belong to this class. "This is the first time we have optical, infrared and radar data on such a small asteroid, which is essentially a meteoroid," Reddy said. "You can think of it as a meteorite floating in space that hasn't hit the atmosphere and made it to the ground -- yet." Small near-Earth asteroids such as 2015 TC25 are in the same size range as meteorites that fall on Earth. Astronomers discover them frequently, but not very much is known about them as they are difficult to characterize. By studying such objects in more detail, astronomers hope to better understand the parent bodies from which these meteorites originate. Asteroids are remaining fragments from the formation of the solar system that mostly orbit the sun between the orbits of Mars and Jupiter today. Near-Earth asteroids are a subset that cross Earth's path. So far, more than 15,000 near-Earth asteroids have been discovered. Scientists are interested in meteoroids because they are the precursors to meteorites impacting Earth, Reddy said. "If we can discover and characterize asteroids and meteoroids this small, then we can understand the population of objects from which they originate: large asteroids, which have a much smaller likelihood of impacting Earth," he said. "In the case of 2015 TC25, the likelihood of impacting Earth is fairly small." The discovery also is the first evidence for an asteroid lacking the typical dust blanket -- called regolith -- of most larger asteroids. Instead, 2015 TC25 consists essentially of bare rock. The team also discovered that it is one of the fastest-spinning near-Earth asteroids ever observed, completing a rotation every two minutes. Probably, 2015 TC25 is what planetary scientists call monolithic, meaning it is more similar to a "solid rock" type of object than a "rubble pile" type of object like many large asteroids, which often consist of many types of rocks held together by gravity and friction. Bennu, the object of the UA-led OSIRIS-REx sample return mission, is believed to be the latter type. As far as the little asteroid's origin is concerned, Reddy believes it probably was chipped off by another impacting rock from its parent, 44 Nysa, a main-belt asteroid large enough to cover most of Los Angeles. "Being able to observe small asteroids like this one is like looking at samples in space before they hit the atmosphere and make it to the ground," Reddy say. "It also gives us a first look at their surfaces in pristine condition before they fall through the atmosphere." The telescope consortium used in this project includes University of Hawaii/NASA IRTF, USRA/Arecibo Planetary Radar, New Mexico Institute of Mining and Technology/Magdalena Ridge Observatory, Northern Arizona University and Lowell Observatory/Discovery Channel Telescope. Reddy's research on 2015 TC25 is funded by NASA's Near-Earth Object Observations program. "Physical Characterization of ~2-Meter Diameter Near-Earth Asteroid 2015 TC25: A Possible Boulder from E-type Asteroid (44) Nysa" by Vishnu Reddy et al, 2016, The Astronomical Journal http://aj. . The paper is online at http://tinyurl.


Gif composed of thirteen delay-Doppler images of Comet 45P/HMP after 2 hours of observation. Credit: Universities Space Research Association Though not visible to the naked eye or even with binoculars, the green-tailed Comet 45P/Honda-Mrkos-Pajdusakova (HMP) did not escape the gaze of the world-renowned Arecibo Observatory. Scientists from the University of Arizona's Lunar and Planetary Laboratory (LPL) and the Universities Space Research Association (USRA) at Arecibo Observatory have been studying the comet with radar to better understand its solid nucleus and the dusty coma that surrounds it. "Comets are remnants of the planet forming process and are part of a group of objects made of water ice and rocky material that formed beyond Neptune," noted Dr. Ellen Howell, Scientist at LPL and the leader of the observing campaign at Arecibo. "Studying these objects gives us an idea of how the outer reaches of our Solar System formed and evolved over time." Studying the comet with radar not only very precisely determines its orbit, allowing scientists to better predict its location in the future, but also gives a glimpse of the typically unseen part, the comet's nucleus, which is usually hidden behind the cloud of gas and dust that makes up the its coma and tail. "The Arecibo Observatory planetary radar system can pierce through the comet's coma and allows us to study the surface properties, size, shape, rotation, and geology of the comet nucleus," said Dr. Patrick Taylor, USRA Scientist and Group Lead for Planetary Radar at Arecibo. "We gain roughly the same amount of knowledge from a radar observation as a spacecraft flyby of the same object, but at considerably less cost." In fact, the new radar observations have revealed Comet 45P/HMP to be somewhat larger than previously estimated. The radar images suggest a size of about 1.3 km (0.8 mi) and that it rotates about once every 7.6 hours. "We see complex structures and bright regions on the comet and have been able to investigate the coma with radar," indicated Cassandra Lejoly, graduate student at the University of Arizona. This comet is only the seventh imaged using radar because comets rarely come close enough to the Earth to get such detailed radar images. In fact, though 45P/HMP has an orbital period of about 5.3 years, it rarely passes close to Earth, as it is doing now. Comet 45P is one of a group of comets called Jupiter family comets (JFCs), whose orbits are controlled by Jupiter's gravity and typically orbit the sun about every 6 years. Comet 45P/HMP, which is passing by Earth at a speed of about 23 km/s (relative to Earth) and a close approach of about 32 Earth-Moon distances, will be observed widely at different wavelengths to characterize the gas and dust emanating from the nucleus that forms the coma. As comets orbit the sun, the ices sublime from solids to gases and escape the nucleus. The nucleus gradually shrinks and will disappear completely within in less than a million years. Radar observations at Arecibo of Comet 45P/HMP began on February 9, 2017 and will continue through February 17, 2017. Explore further: Comet's trip past Earth offers first in a trio of opportunities


News Article | February 6, 2017
Site: www.techtimes.com

The dwarf planet Ceres continues to amaze. The big surprise was in 2015 when NASA's Dawn spacecraft discovered a mini Everest-sized icy volcano. The lonely volcano triggered thought waves on why it is so alone with no companions. Here comes a new study that says Ahuna Mons is not alone and thousands of other ice volcanoes billions of years old might have flattened out, leaving it all alone. The 2.5-mile-tall ice volcano was a puzzle to scientists considering its solo nature and if the new theory holds up, Ahuna Mons must have many hidden volcanic siblings. The findings came from a study to be published in Geophysical Research Letters, which said ice volcanoes aged millions or billions of years might have existed on Ceres. But they flattened out as time passed and left Ahuna Mons as a solitary structure. "If you see one thing on a planet and nothing else that looks like nothing else, that's sort of strange," Michael Sori of the Lunar and Planetary Laboratory at the University of Arizona and the lead author told Inverse. What has heightened the interest on the icy volcanoes of Ceres is its proximity to the sun, unlike other icy worlds that are too far from the hot star. Considering the position of Ceres as part of the asteroid belt, having icy volcanoes is quite unusual. "Ceres is just barely far enough from the sun for this to work," Sori said. The presence of ice volcanoes has been reported from dwarf planets and moons, like Pluto, Europa, Triton, Charon, and Titan. But they are far from the sun. "But it's also why it makes it interesting because it's the warmest place where it's affected," he noted. The researchers analyzed the question why Ahuna Mons is all alone. Is it the only volcano the Ceres ever had or is it the only one that is visible and others are invisible? The researchers pitched the second possibility of invisibility of the peer volcanoes and said Ahuna Mons was left alone as other volcanoes vanished over millions of years. "We think we have a very good case that there have been lots of cryovolcanoes on Ceres but they have deformed," Sori said. The researchers also put forward a hypothesis noting that unlike Earth, Ceres is bereft of an atmosphere that would wear down volcanoes through rain, ice, or wind. So the valid option is a flattening out of the volcanoes over eons of time in a process called "viscous relaxation." The scientists explained that viscous relaxation is akin to a block of honey changing structure - first it's solid but takes a flat structure as time passes. Also, Earth has a record of glaciers flowing out because of viscous relaxation. That process applies well to Ceres, considering the icy composition of the volcanoes, which turned flat as billions of years passed and the volcanic structures became indistinguishable. "Ahuna Mons is at most 200 million years old. It just has not had time to deform," Sori said. If the flattening of the Ahuna Mons were to happen, it will be an average 30 to 160 feet for every million year it has existed, he added. A study in 2016 found that the craters of Ceres are filled with water-ice. One school of opinion is that if humans start living in outer space and other planets, then the mining of Ceres and other icy worlds will be imperative for securing water. © 2017 Tech Times, All rights reserved. Do not reproduce without permission.


News Article | February 21, 2017
Site: www.futurity.org

Bumble bees tagged with microchips are offering insights into the daily lives of a colony. While most bees are generalists collecting both pollen and nectar over the course of their lifetime, individual workers tend to specialize on one of the two during any given day, dedicating more than 90 percent of their foraging sorties to either pollen or nectar. The observations also reveal that individual bumble bee workers differ vastly in terms of foraging activity. Just like honey bees, bumble bees (Bombus impatiens) play important roles as pollinators, helping with agriculture and fruit production. But despite the ecological services they provide, many aspects of their biology still remain a mystery. By outfitting each bumble bee with a radio frequency identification (RFID) tag—similar to the sensors that protect merchandise from shoplifters—researchers were able to keep tabs on them at all times and log the data automatically instead of relying on human observations limited to certain times. “The way these studies have typically been done requires a human observer sitting in front of a hive entrance and taking notes all day, and nobody wants to do that,” says Avery Russell, a doctoral student in entomology and insects in the lab of Daniel Papaj, professor of ecology and evolutionary biology at the University of Arizona. “With the RFID chips, we can track every nectar and pollen collection trip made over each worker’s lifespan and a portion of the colony’s lifespan.” Researchers then used the data to determine how patterns of specialization on each food type differed at timescales of a day or over a lifetime. Once a bumble bee queen has mated, she burrows into the ground and overwinters. The following spring, she emerges and starts a hive that lasts until the fall. A typical bumble bee colony grows to about 75 workers, with about 40 to 50 going out and foraging on flowers for nectar and pollen. After the colony’s growth phase, the colony produces unfertilized eggs that hatch into males. The male bumble bees then disperse in search for other unmated queens to begin the cycle anew. “Each individual bee only lives between two weeks to a month at the most,” says Russell, lead author of the study that is published in the journal Scientific Reports. “And even though they behave as generalists over their lifetime, our study showed that they tend to specialize on one food source over the course of a foraging day.” The researchers were surprised to find a big difference in efficiency, with the most active foragers making 40 times the number of trips each day as the least active workers. “Interestingly, when we studied the morphology between very active foragers and workers that barely leave the hive, we found that bees with more sensitive antennae foraged more,” Russell says. Similar variation has been in observed in honey bees and other eusocial species, where some workers are much more active than others, but no one had seen it to this extreme due to the limits of human observations. “If you watch a bee only for an hour or so, you can’t say what it will do over the course of a few days or over its whole life,” Russell says. “We don’t yet know why, but it could be that workers that forage less do so because they aren’t quite as skilled at foraging as others and make themselves useful by doing more around the hive.” To track the bees’ behavior, the team superglued tiny RFID tags to the backs of the bees. Each tag weighs only 2 to 3 percent of the bee’s weight. A Y-tube connects the hive to two arenas, one that offers pollen and one that offers nectar. When a bee leaves the hive to forage, it can choose to go to the pollen chamber or the nectar chamber. Two RFID readers mounted at the entrance keep track of the bees going in and out and help the researchers collect a wealth of data. “This setup gives us information about directionality,” Russell explains. “Is the forager leaving or returning from foraging? We also get an idea of whether a bee goes from one chamber to the other, or whether it makes repeated trips to only one chamber, and we get to know how long the trips were.” Since the team was especially interested in the sequence of the foraging trips over the course of the day, some heavy lifting was needed to make sense of all the data, so Russell enlisted the help of Sarah Morrison, a doctoral student in the UA’s Lunar and Planetary Laboratory, who studies orbital dynamics and the evolution of solar systems. “Each RFID reader only spits out timestamps and the identity of the bee, so if you want to know what the bees are doing, you need to parse all that information and turn it into things we can understand,” Russell says. “For example, how many trips a forager makes per day.” While honey bees are known to be very consistent and tend to stick to one species of plant and often one type of reward over a day, a phenomenon known as floral consistency, bumble bees were thought to be more generalist. So researchers were somewhat surprised to find the bees tend to make strings of foraging runs for the same reward on a given day. “One possible explanation is that foraging for pollen versus nectar requires very different behavioral regimes, so it makes sense for them to focus on one at a time,” he says. “Also, in many cases pollen and nectar are not both available from the same plant species.” Researchers still don’t know why bees switch between foraging for nectar or pollen. “It is possible they take cues from the brood,” Russell says, “in that they produce pheromones that say ‘we need more of this or more of that.'” Bumble bees that specialize in a task, either over the course of their lifetime or over the course of a foraging day, turned out to be no more active than their generalist peers, however. Neither were they found to be larger, more able foragers—raising the question as to why they specialize in the first place. “One of the reasons bees might specialize could be some sort of memory constraint,” Russell says. “Rather than having to switch back and forth between dealing with many different floral designs and constructions, it might be more efficient to just stick with one for the duration of a foraging day.” As for the more domestic individuals that were found to forage far less than their more adventurous colleagues, Russell says that this might reflect economics of skill allocation. “Those that are less good at foraging probably shouldn’t go foraging in the first place,” he explains, “as that requires a lot of learning how to recognize a flower and how to collect the nectar. Foragers hone their skills over dozens, if not hundreds, of visits until they figure out how to efficiently pry open the lips of a snapdragon flower, for example. Plus, they have to use visual and olfactory cues to learn which are the rewarding and the non-rewarding flowers.”


News Article | February 18, 2017
Site: phys.org

Just like their domesticated cousins, the honey bees, bumblebees play important roles as pollinators, thus helping in agriculture and fruit production. But despite the ecological services they provide, many aspects of their biology still remain a mystery. By outfitting each bumblebee with a radio frequency identification, or RFID, tag—similar to the ones used to protect merchandise from shoplifters—the researchers were able to keep tabs on them at all times and log the data automatically instead of relying on human observations limited to certain times. "The way these studies have typically been done requires a human observer sitting in front of a hive entrance and taking notes all day, and nobody wants to do that," says Avery Russell, the lead author of the study. Russell is a doctoral student in entomology and insect in the lab of Daniel Papaj, a professor in the University of Arizona's Department of Ecology and Evolutionary Biology. "With the RFID chips, we can track every nectar and pollen collection trip made over each worker's lifespan and a portion of the colony's lifespan." The researchers then used this data to determine how patterns of specialization on each food type differed at timescales of a day or over a lifetime. The results are published in the journal Scientific Reports. Once a bumblebee queen has mated, she burrows into the ground and overwinters. The following spring, she emerges and starts a hive that lasts until the fall. A typical bumblebee colony grows to about 75 workers, with about 40 to 50 going out and foraging on flowers for nectar and pollen. After the colony's growth phase, the colony produces unfertilized eggs that hatch into males. The male bumblebees then disperse in search for other unmated queens to begin the cycle anew. "Each individual bee only lives between two weeks to a month at the most," Russell says, "and even though they behave as generalists over their lifetime, our study showed that they tend to specialize on one food source over the course of a foraging day." The researchers were surprised to find a vast difference in efficiency, with the most active foragers making 40 times the number of trips each day as the least active workers. "Interestingly, when we studied the morphology between very active foragers and workers that barely leave the hive, we found that bees with more sensitive antennae foraged more," Russell said. Similar variation has been in observed in honey bees and other eusocial species, where some workers are much more active than others, but no one had seen it to this extreme due to the limits of human observations. "If you watch a bee only for an hour or so, you can't say what it will do over the course of a few days or over its whole life," Russell says. "We don't yet know why, but it could be that workers that forage less do so because they aren't quite as skilled at foraging as others and make themselves useful by doing more around the hive." To track the bees' behavior, the team superglues tiny RFID tags to the backs of the bees. Each tag weighs only 2 to 3 percent of the bee's weight. A Y-tube connects the hive to two arenas, one that offers pollen and one that offers nectar. When a bee leaves the hive to forage, it can choose to go to the pollen chamber or the nectar chamber. Two RFID readers mounted at the entrance keep track of the bees going in and out and help the researchers collect a wealth of data. "This setup gives us information about directionality," Russell explains. "Is the forager leaving or returning from foraging? We also get an idea of whether a bee goes from one chamber to the other, or whether it makes repeated trips to only one chamber, and we get to know how long the trips were." Since the team was especially interested in the sequence of the foraging trips over the course of the day, some heavy lifting was needed to make sense of all the data. To do this, Russell enlisted the help of Sarah Morrison, a doctoral student in the UA's Lunar and Planetary Laboratory, who studies orbital dynamics and the evolution of solar systems. "Each RFID reader only spits out timestamps and the identity of the bee, so if you want to know what the bees are doing, you need to parse all that information and turn it into things we can understand," Russell says. "For example, how many trips a forager makes per day." While honey bees are known to be very consistent and tend to stick to one species of plant and often one type of reward over a day, a phenomenon known as floral consistency, bumblebees were thought to be more generalist. The present study came somewhat as a surprise in that Russell's team found the bees tend to make strings of foraging runs for the same reward on a given day. "One possible explanation is that foraging for pollen versus nectar requires very different behavioral regimes, so it makes sense for them to focus on one at a time," he says. "Also, in many cases pollen and nectar are not both available from the same plant species." Researchers still don't know why bees switch between foraging for nectar or pollen. "It is possible they take cues from the brood," Russell says, "in that they produce pheromones that say 'we need more of this or more of that.'" Bumblebees that specialize in a task, either over the course of their lifetime or over the course of a foraging day, turned out to be no more active than their generalist peers, however. Neither were they found to be larger, more able foragers—raising the question as to why they specialize in the first place. "One of the reasons bees might specialize could be some sort of memory constraint," Russell says. "Rather than having to switch back and forth between dealing with many different floral designs and constructions, it might be more efficient to just stick with one for the duration of a foraging day." As for the more domestic individuals that were found to forage far less than their more adventurous colleagues, Russell says that this might reflect economics of skill allocation. "Those that are less good at foraging probably shouldn't go foraging in the first place," he explains, "as that requires a lot of learning how to recognize a flower and how to collect the nectar. Foragers hone their skills over dozens, if not hundreds, of visits until they figure out how to efficiently pry open the lips of a snapdragon flower, for example. Plus, they have to use visual and olfactory cues to learn which are the rewarding and the non-rewarding flowers." Explore further: Bees able to spot which flowers offer best rewards before landing More information: Avery L. Russell et al, Patterns of pollen and nectar foraging specialization by bumblebees over multiple timescales using RFID, Scientific Reports (2017). DOI: 10.1038/srep42448


News Article | February 17, 2017
Site: www.eurekalert.org

RFID chips similar to the ones used to protect merchandise from shoplifting have granted an interdisciplinary team of UA researchers unprecedented glimpses into a colony of bumblebees. By tagging individual bumblebees with microchips, biologists have gained insights into the daily life of a colony of bumblebees (Bombus impatiens) in unprecedented detail. The team found that while most bees are generalists collecting both pollen and nectar over the course of their lifetime, individual workers tend to specialize on one of the two during any given day, dedicating more than 90 percent of their foraging sorties to either pollen or nectar. The observations also revealed that individual bumblebee workers differ vastly in terms of their foraging activity. Just like their domesticated cousins, the honey bees, bumblebees play important roles as pollinators, thus helping in agriculture and fruit production. But despite the ecological services they provide, many aspects of their biology still remain a mystery. By outfitting each bumblebee with a radio frequency identification, or RFID, tag -- similar to the ones used to protect merchandise from shoplifters -- the researchers were able to keep tabs on them at all times and log the data automatically instead of relying on human observations limited to certain times. "The way these studies have typically been done requires a human observer sitting in front of a hive entrance and taking notes all day, and nobody wants to do that," says Avery Russell, the lead author of the study. Russell is a doctoral student in entomology and insect in the lab of Daniel Papaj, a professor in the University of Arizona's Department of Ecology and Evolutionary Biology. "With the RFID chips, we can track every nectar and pollen collection trip made over each worker's lifespan and a portion of the colony's lifespan." The researchers then used this data to determine how patterns of specialization on each food type differed at timescales of a day or over a lifetime. The results are published in the journal Scientific Reports. Once a bumblebee queen has mated, she burrows into the ground and overwinters. The following spring, she emerges and starts a hive that lasts until the fall. A typical bumblebee colony grows to about 75 workers, with about 40 to 50 going out and foraging on flowers for nectar and pollen. After the colony's growth phase, the colony produces unfertilized eggs that hatch into males. The male bumblebees then disperse in search for other unmated queens to begin the cycle anew. "Each individual bee only lives between two weeks to a month at the most," Russell says, "and even though they behave as generalists over their lifetime, our study showed that they tend to specialize on one food source over the course of a foraging day." The researchers were surprised to find a vast difference in efficiency, with the most active foragers making 40 times the number of trips each day as the least active workers. "Interestingly, when we studied the morphology between very active foragers and workers that barely leave the hive, we found that bees with more sensitive antennae foraged more," Russell said. Similar variation has been in observed in honey bees and other eusocial species, where some workers are much more active than others, but no one had seen it to this extreme due to the limits of human observations. "If you watch a bee only for an hour or so, you can't say what it will do over the course of a few days or over its whole life," Russell says. "We don't yet know why, but it could be that workers that forage less do so because they aren't quite as skilled at foraging as others and make themselves useful by doing more around the hive." To track the bees' behavior, the team superglues tiny RFID tags to the backs of the bees. Each tag weighs only 2 to 3 percent of the bee's weight. A Y-tube connects the hive to two arenas, one that offers pollen and one that offers nectar. When a bee leaves the hive to forage, it can choose to go to the pollen chamber or the nectar chamber. Two RFID readers mounted at the entrance keep track of the bees going in and out and help the researchers collect a wealth of data. "This setup gives us information about directionality," Russell explains. "Is the forager leaving or returning from foraging? We also get an idea of whether a bee goes from one chamber to the other, or whether it makes repeated trips to only one chamber, and we get to know how long the trips were." Since the team was especially interested in the sequence of the foraging trips over the course of the day, some heavy lifting was needed to make sense of all the data. To do this, Russell enlisted the help of Sarah Morrison, a doctoral student in the UA's Lunar and Planetary Laboratory, who studies orbital dynamics and the evolution of solar systems. "Each RFID reader only spits out timestamps and the identity of the bee, so if you want to know what the bees are doing, you need to parse all that information and turn it into things we can understand," Russell says. "For example, how many trips a forager makes per day." While honey bees are known to be very consistent and tend to stick to one species of plant and often one type of reward over a day, a phenomenon known as floral consistency, bumblebees were thought to be more generalist. The present study came somewhat as a surprise in that Russell's team found the bees tend to make strings of foraging runs for the same reward on a given day. "One possible explanation is that foraging for pollen versus nectar requires very different behavioral regimes, so it makes sense for them to focus on one at a time," he says. "Also, in many cases pollen and nectar are not both available from the same plant species." Researchers still don't know why bees switch between foraging for nectar or pollen. "It is possible they take cues from the brood," Russell says, "in that they produce pheromones that say 'we need more of this or more of that.'" Bumblebees that specialize in a task, either over the course of their lifetime or over the course of a foraging day, turned out to be no more active than their generalist peers, however. Neither were they found to be larger, more able foragers -- raising the question as to why they specialize in the first place. "One of the reasons bees might specialize could be some sort of memory constraint," Russell says. "Rather than having to switch back and forth between dealing with many different floral designs and constructions, it might be more efficient to just stick with one for the duration of a foraging day." As for the more domestic individuals that were found to forage far less than their more adventurous colleagues, Russell says that this might reflect economics of skill allocation. "Those that are less good at foraging probably shouldn't go foraging in the first place," he explains, "as that requires a lot of learning how to recognize a flower and how to collect the nectar. Foragers hone their skills over dozens, if not hundreds, of visits until they figure out how to efficiently pry open the lips of a snapdragon flower, for example. Plus, they have to use visual and olfactory cues to learn which are the rewarding and the non-rewarding flowers."

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