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By Erik Stokstad Dogs are renowned for their world-class noses, but a new study suggests they may have an additional—albeit hidden—sensory talent: a magnetic compass. The sense appears to allow them to use Earth’s magnetic field to calculate shortcuts in unfamiliar terrain. The finding is a first in dogs, says Catherine Lohmann, a biologist at the University of North Carolina, Chapel Hill, who studies “magnetoreception” and navigation in turtles. She notes that dogs’ navigational abilities have been studied much less compared with migratory animals such as birds. “It’s an insight into how [dogs] build up their picture of space,” adds Richard Holland, a biologist at Bangor University who studies bird navigation. There were already hints that dogs—like many animals, and maybe even humans—can perceive Earth’s magnetic field. In 2013, Hynek Burda, a sensory ecologist at the Czech University of Life Sciences Prague who has worked on magnetic reception for 3 decades, and colleagues showed dogs tend to orient themselves north-south while urinating or defecating. Because this behavior is involved in marking and recognizing territory, Burda reasoned the alignment helps dogs figure out the location relative to other spots. But stationary alignment isn’t the same thing as navigation. In the new study, Burda’s graduate student, Kateřina Benediktová, initially put video cameras and GPS trackers on four dogs and took them on trips into the forest. The dogs would scamper off to chase the scent of an animal for 400 meters on average. The GPS tracks showed two types of behavior during their return trips to their owner (see map, below). In one, dubbed tracking, a dog would retrace its original route, presumably following the same scent. In the other behavior, called scouting, the dog would return along a completely new route, bushwhacking without any backtracking. Benediktová et al., eLife (2020) 10.7554 (CC BY) © 2020 American Association for the Advancement of Science.

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 27374 - Posted: 07.18.2020

By Joshua Sokol As an astronomer at Chicago’s Adler Planetarium, Lucianne Walkowicz usually has to stretch to connect the peculiarities of space physics with things that people experience on Earth. Then came the email about whales. Sönke Johnsen, a biologist at Duke University, told Dr. Walkowicz that his team had stumbled upon a bizarre correlation: When the surface of the sun was pocked with dark sunspots, an indicator of solar storms, gray whales and other cetacean species seemed more likely to strand themselves on beaches. The team just needed an astronomer’s help wrangling the data. “This was like a dream request,” Dr. Walkowicz said. “And I finally got to do something in marine biology, even though I didn’t study it.” With that assistance, there is some evidence of this peculiar correlation, the researchers said in a paper published Monday in Current Biology. “The study convinced me there is a relationship between solar activity and whale strandings,” said Kenneth Lohmann, a biologist at the University of North Carolina who did not participate in the research. This coincidence across 93 million miles of space is more plausible than it might seem. Sunspots are a harbinger of heightened solar weather, marking times when the tangled plasma of the sun’s atmosphere coughs out more photons and charged particles than usual. These disturbances sail outward and smash into our planet’s magnetic field, creating colorful light shows like the aurora borealis and sometimes disrupting communications. Biologists have already demonstrated that many animals can navigate by somehow sensing Earth’s magnetic field lines. Gray whales, which migrate over 10,000 miles a year through a featureless expanse of blue, might be relying on a similar hidden sense. But unlike a migrating bird, a whale is not easily placed in a magnetized box for controlled experiments. Instead, Jesse Granger, a Duke graduate student, looked at whale strandings, which previous studies had suggested seemed to track with sunspot activity. She narrowed a list of gray whale strandings kept by the National Oceanic and Atmospheric Administration, to highlight the percentage of whales that were stranded alive, as well as whales that were released back to sea and seemed to recover. In theory, those cases were examples of healthy whales that had merely taken a wrong turn. © 2020 The New York Times Company

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 27076 - Posted: 02.27.2020

By Elizabeth Pennisi Over 20 years, citizen scientists across North America tagged more than 1 million monarch butterflies as they flitted their way southward on one of nature’s more mysterious migrations. Now, scientists analyzing data from those journeys have discovered what may trigger them: the angle of the high noon Sun—which changes over time and as one moves closer to the equator. That “critical environmental factor” also seems to help monarchs time their daily travels and the end of their fall migration, says Steven Reppert, a neurobiologist at the University of Massachusetts Medical School in Worcester who studies monarch migrations, but was not involved with this work. As a result, adds University of California, Berkeley, evolutionary biologist Noah Whiteman, “a marvel of the natural world is a little closer to being understood.” The annual migration of monarchs (Danaus plexippus) from across the United States and eastern Canada to one small region of southwestern Mexico has long defied understanding. Ten years ago, lab and field studies showed that these butterflies have an internal clock in their antennae that helps them navigate based on the horizontal movements of the Sun. But no one knew what the trigger for their trek was—or how they paced their daily journeys. To learn more, a nonprofit organization called Monarch Watch began to distribute pinkie nail–size adhesive tags to thousands of volunteers, who put them on monarchs flying through their area and recorded the dates and locations of each tagging. From 1998 to 2015, more than 1.38 million butterflies were tagged, says Orley Taylor, an insect ecologist at the University of Kansas in Lawrence who started the program in 1992. After the butterflies arrived at their destination in southwestern Mexico, volunteers there searched for the tags. Altogether, they gathered more than 13,000. © 2019 American Association for the Advancement of Science.

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 26903 - Posted: 12.19.2019

David Barrie Until the arrival of GPS, the magnetic compass was the single most useful navigational tool available to humans. But it’s a recent invention. Although Chinese explorers understood the principles of the compass earlier, it entered service in Europe in the 12th century. Other animals have been magnetic navigators for much, much longer. Many different species—ranging from newts and insects to sea turtles, fish, and birds—are able to orient themselves relative to the Earth’s magnetic field. Among mammals, naked mole rats, deer, and even dogs also seem to have this gift. Researchers have recently shown that the brainwaves of human beings respond to changes in magnetic fields, though it’s far from clear whether or not we can make any navigational use of this effect. But how all these different species actually detect the Earth’s magnetic field remains largely mysterious. We know that certain bacteria that respond to magnetic fields carry within them crystalline chains of the mineral magnetite, which enables their alignment with the magnetic field in a passive way—just like the needle of a compass. This simple mechanism helps these microbes swim toward the oxygen-deprived depths where many species flourish. Magnetite also seems to be a promising candidate for a “magnetoreceptor” in multicellular organisms. An array of a few million cells containing magnetite could be used to detect small changes in the intensity of the Earth’s magnetic field. Magnetite is found in many organisms, and it is clearly involved in the magnetic sense possessed by some fish. © 1986–2019 The Scientist

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 26357 - Posted: 06.26.2019

By Carl Zimmer Last week, ladybugs briefly took over the news cycle. Meteorologists at the National Weather Service were looking over radar images in California on the night of June 4 when they spotted what looked like a wide swath of rain. But there were no clouds. The meteorologists contacted an amateur weather-spotter directly under the mysterious disturbance. He wasn’t getting soaked by rain. Instead, he saw ladybugs. Everywhere. Radar apparently had picked up a cloud of migrating ladybugs spread across 80 miles, with a dense core ten miles wide floating 5,000 feet to 9,000 feet in the air. As giant as the swarm was, the meteorologists lost track of it. The ladybugs disappeared into the night. Compared to other animal migrations, the migrations of insects are a scientific mystery. It’s easy to spot a herd of wildebeest making its way across the savanna. Insects, even in huge numbers, move from place to place without much notice. One day you look around, and ladybugs are everywhere. “The migrations themselves are totally invisible,” said Jason Chapman, an ecologist at the University of Exeter in Britain. Dr. Chapman and his colleagues are using radar to bring insect migrations to light. The scientists help run a unique network of small radar stations in southern England designed to scan the sky 24 hours a day, spotting insects flying overhead. “These radars are fantastic,” said Dr. Chapman. “We have a lot of information about every individual insect that flies over overhead, including a measure of the shape and a measure of their size.” © 2019 The New York Times Company

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 26329 - Posted: 06.14.2019

Yao-Hua Law When it comes to migration science, birds rule. Although many mammals — antelopes, whales, bats — migrate, too, scientists know far less about how those animals do it. But a new device, invented by animal navigation researcher Oliver Lindecke, could open a new way to test how far-ranging bats find their way. Lindecke, of Leibniz Institute for Zoo and Wildlife Research in Germany, has been studying bat migration since 2011. He started with analyzing different forms of hydrogen atoms in wild bats to infer where they had flown from. But figuring out how the bats knew where to go was trickier. Lindecke needed a field setup that let him test what possible cues from nature helped bats navigate across vast distances. The first step was studying in which direction the bats first take flight. Such experiments on birds typically involve confining the animals in small, enclosed spaces. But that doesn’t work for bats, which tend to fall asleep in such spaces. So he invented what he calls the circular release box: a flat-bottom, funnel-shaped container topped by a wider lid. To escape, the bat crawls up the wall and takes off from the edge. Bat tracks in a layer of chalk (Lindecke says he was inspired by a snow-covered Berlin street) indicate where the bat took off. In August 2017, Lindecke captured 54 soprano pipistrelle bats (Pipistrellus pygmaeus) in a large, 50-meter-wide trap at the Pape Ornithological Research Station in Latvia as the animals were migrating along the coast of the Baltic Sea toward Central Europe. Experiments with the new device showed that the adult bats flew straight in the direction in which they took off, Lindecke and colleagues report online March 1 in the Journal of Zoology. |© Society for Science & the Public 2000 - 2019

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 13: Memory and Learning
Link ID: 26159 - Posted: 04.20.2019

By C. Claiborne Ray Q. How do bees find the flowers in the container garden on the fourth-floor deck of my city apartment? A. Foraging bees use the same methods to find nectar and pollen four floors up that they use at ground level. Honeybees routinely fly two miles from their hives in their search for raw material for honey; it doesn’t require much extra energy to fly several stories up. It takes only one scout to report a promising garden to the rest of the hive with a famous waggle dance. The scout relies on its sophisticated eyes, which are tuned to a variety of wavelengths, including ultraviolet color patterns in flowers that are invisible to people. We’re taking you on a journey to help you understand how bees, while hunting for pollen, use all of their senses — taste, touch, smell and more — to decide what to pick up and bring home. When the bees get closer to flowers, smell receptors begin transmitting information. And it has recently been discovered that both bumblebees and honeybees can detect and discriminate among weak electrostatic fields emanating from flowers. The bees accumulate a positive charge, while the flowers have a negative charge. The interaction between the fields is detected by antennae or sensitive hairs on the body. The electrical field helps bees to recognize pollen-rich blooms and perhaps even to transfer the pollen. © 2019 The New York Times Company

Related chapters from BN: Chapter 19: Language and Lateralization; Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 15: Language and Lateralization; Chapter 5: The Sensorimotor System
Link ID: 26102 - Posted: 04.02.2019

By JoAnna Klein Every spring in Australia, billions of bogong moths migrate from the arid plains of Queensland, New South Wales and Victoria to the meadows of the Australian Alps to escape the impending heat. There, they congregate in caves like living shingles, and go dormant over the summer. Autumn arrives, and they return to their birthplaces to mate, lay eggs and die. The eggs hatch into caterpillars that develop underground through winter. The cycle continues. How these animals complete this epic journey to a place they’ve never been and back, traveling hundreds of miles at night, for days to weeks each way, has long been a mystery. But scientists have now discovered that bogong moths have a magnetic sense to help them. In a paper published Thursday in Current Biology, they tested how the moths reacted to moving visual cues and magnetic fields in an outdoor flight simulator and found that the winged insects use magnetic fields like a compass. While other animals like nocturnal songbirds and sea turtles are known to migrate by Earth’s magnetic fields, the researchers say this is the first reliable evidence that insects can, too. Australia’s small, brown, ordinary-looking bogong moths are the only known insect besides the monarch butterfly to manage such a long, directed and specific migration. “They have this sort of amazing ability that belies their appearance,” said Eric Warrant, a biologist at the University of Lund in Sweden and the principal investigator of the study. “It’s as if the bogong moth is the dreary-colored, nocturnal cousin of the monarch butterfly.” But unlike the monarch, which flies during the day by a reliably rising and setting sun, the moth flies at night beneath dim constellations and a darting, shape-shifting moon. © 2018 The New York Times Company

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 25121 - Posted: 06.22.2018

Merrit Kennedy What makes a group of animals genetically similar to each other? Traditionally, scientists have thought that animals living near each other are more likely to have things in common genetically. Another explanation is that animals living in similar environments — like high altitudes or hot temperatures — might evolve in similar ways. But loggerhead sea turtles appear to have broken that common wisdom. Their genetic similarities are closely linked to the magnetic field of the nesting area where they were born, according to new research from scientists at the University of North Carolina, Chapel Hill, published in Current Biology. And that magnetic imprinting is a better indicator of genetic similarity than that of groups of turtles that live near each other or in similar environments, says J. Roger Brothers, the lead author of the study. "A lot of different animals including sea turtles detect Earth's magnetic field and then derive navigational information from it and use it to find their way across or throughout long-distance migrations," Brothers says. Turtles likely "imprint" to the magnetic field of their nesting area at a very young age or even before they hatch. This acts like a kind of compass for them, he says, even as they leave the East Coast of the U.S. and travel hugely long distances, in some cases all the way to Africa. © 2018 npr

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 24867 - Posted: 04.14.2018

Dan Garisto Birds can sense Earth’s magnetic field, and this uncanny ability may help them fly home from unfamiliar places or navigate migrations that span tens of thousands of kilometers. For decades, researchers thought iron-rich cells in birds’ beaks acted as microscopic compasses (SN: 5/19/12, p. 8). But in recent years, scientists have found increasing evidence that certain proteins in birds’ eyes might be what allows them see magnetic fields (SN: 10/28/09, p. 12). Scientists have now pinpointed a possible protein behind this “sixth sense.” Two new studies — one examining zebra finches published March 28 in Journal of the Royal Society Interface, the other looking at European robins published January 22 in Current Biology — both single out Cry4, a light-sensitive protein found in the retina. If the researchers are correct, this would be the first time a specific molecule responsible for the detection of magnetic fields has been identified in animals. “This is an exciting advance — we need more papers like these,” says Peter Hore, a chemist at the University of Oxford who has studied chemical reactions involved in bird navigation. Cry4 is part of a class of proteins called cryptochromes, which are known to be involved in circadian rhythms, or biological sleep cycles (SN: 10/02/17, p. 6). But at least some of these proteins are also thought to react to Earth’s magnetic field thanks to the weirdness of quantum mechanics (SN: 7/23/16, p. 8). The protein’s quantum interactions could help birds sense this field, says Atticus Pinzon-Rodriguez, a biologist at the University of Lund in Sweden who was involved with the zebra finch study. |© Society for Science & the Public 2000 - 2018.

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 7: Vision: From Eye to Brain
Link ID: 24814 - Posted: 04.03.2018

By Helen Briggs BBC News They migrate thousands of kilometres across the sea without getting lost. The Arctic tern, for instance, spends summer in the UK, then flies to the Antarctic for the winter. Yet, scientists are still unsure exactly how birds perform such extreme feats of migration, arriving in the right place every year. According to new research, smell plays a key role when birds are navigating long distances over the ocean. Researchers from the universities of Oxford, Barcelona and Pisa temporarily removed seabirds' sense of smell before tracking their movements. They found the birds could navigate normally over land, but appeared to lose their bearings over the sea. This suggests that they use a map of smells to find their way when there are no visual cues. Previous experiments had suggested that removing birds' sense of smell impairs homing ability. However, some had questioned whether sensory deprivation might impair some other function, such as the ability to search for food. ''Our new study eliminates these objections, meaning it will be very difficult in future to argue that olfaction is not involved in long-distance oceanic navigation in birds,'' said study researcher Oliver Padget of Oxford University's Department of Zoology. The researchers studied 30 Scopoli's shearwaters living off the coast of Menorca. The birds nest in the Mediterranean, but spend the non-breeding season in the Atlantic, including areas off the west coast of Africa and the east coast of Brazil. Some of the birds were made to temporarily lose their sense of smell through nasal irrigation with zinc sulphate; another group carried small magnets; and a third group acted as a control. © 2017 BBC.

Related chapters from BN: Chapter 9: Hearing, Balance, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 24010 - Posted: 08.30.2017

By STEPH YIN European eels are born and die in the North Atlantic Ocean, but spend most of their lives in rivers or estuaries across Europe and North Africa. In between, they traverse thousands of miles of ocean, where it’s often unclear which way is up or down. Scientists have therefore long suspected that these critically endangered fish use magnetism to help guide them. A study published Friday in Science Advances shows, for the first time, that European eels might link magnetic cues with the tides to navigate. Studying juveniles during the crucial stage when they move toward land from open ocean, the authors found that eels faced different directions based on whether the tide was flowing in (flood tide) or out (ebb tide). Changing orientation might help eels take advantage of tides to travel from the ocean to the coast, and into fresh water, more efficiently, said Alessandro Cresci, a graduate student at the University of Miami and lead author of the study. Previous studies have shown that eels can detect magnetic fields, but how they use this sixth sense “has remained a matter of speculation” until now, said Michael J. Miller, an eel biologist at Nihon University in Japan who was not involved in the study. When transitioning from sea to coast, European eels are in a stage of their lives where they are about the size of a finger and transparent along their bodies, thus the name “glass eels.” Mr. Cresci’s group studied glass eels from the coast of Norway, observing the animals in the field by putting 54 slippery, see-through eels, one by one, in a drifting chamber equipped with cameras and compasses. When the tide ebbed, these animals generally faced south, but when it flowed in, they showed no consistent orientation. The researchers then studied 49 of the same eels in laboratory tanks. They subjected some of the eels to reoriented magnetic fields, rotating magnetic north to the east, south or west. © 2017 The New York Times Company

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 23728 - Posted: 06.12.2017

Laura Beil Scientists have shown why fruit flies don’t get lost. Their brains contain cells that act like a compass, marking the direction of flight. It may seem like a small matter, but all animals — even Siri-dependent humans — have some kind of internal navigation system. It’s so vital to survival that it is probably linked to many brain functions, including thought, memory and mood. “Everyone can recall a moment of panic when they took a wrong turn and lost their sense of direction,” says Sung Soo Kim of the Howard Hughes Medical Institute’s Janelia Research Campus in Ashburn, Va. “This sense is central to our lives.” But it’s a complex system that is still not well understood. Human nerve cells involved in the process are spread throughout the brain. In fruit flies, the circuitry is much more straightforward. Two years ago, Janelia researchers reported that the flies appear to have a group of about 50 cells connected in a sort of ring in the center of their brains that serve as an internal compass. But the scientists could only theorize how the system worked. In a series of experiments published online May 4 in Science, Kim and his Janelia colleagues describe how nerve cell activity in the circle changes when the insects fly. The scientists tethered Drosophila melanogaster flies to tiny metal rods that kept them from wriggling under a microscope. Each fly was then surrounded with virtual reality cues — like a passing landscape — that made it think it was moving. As a fly flapped its wings, the scientists recorded which nerve cells, or neurons, were active, and when. The experiments clusters of about four to five neurons would fire on the side of the ring corresponding to the direction of flight: one part of the ring for forward, another next to it for left, and so on. |© Society for Science & the Public 2000 - 2017.

Related chapters from BN: Chapter 17: Learning and Memory
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 23578 - Posted: 05.05.2017

By Elizabeth Pennisi By standing on the shoulders of giants, humans have built the sophisticated high-tech world we live in today. Tapping into the knowledge of previous generations—and those around us—was long thought to be a “humans-only” trait. But homing pigeons can also build collective knowledge banks, behavioral biologists have discovered, at least when it comes to finding their way back to the roost. Like humans, the birds work together and pass on information that lets them get better and better at solving problems. “It is a really exciting development in this field,” says Christine Caldwell, a psychologist at the University of Stirling in the United Kingdom who was not involved with the work. Researchers have admired pigeon intelligence for decades. Previous work has shown the birds are capable of everything from symbolic communication to rudimentary math. They also use a wide range of cues to find their way home, including smell, sight, sound, and magnetism. On its own, a pigeon released multiple times from the same place will even modify its navigation over time for a more optimal route home. The birds also learn specific routes from one another. Because flocks of pigeons tend to take more direct flights home than individuals, scientists have long thought some sort of “collective intelligence” is at work. © 2017 American Association for the Advancement of Science

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 23504 - Posted: 04.18.2017

Laurel Hamers Earth’s magnetic field helps eels go with the flow. The Gulf Stream fast-tracks young European eels from their birthplace in the Sargasso Sea to the European rivers where they grow up. Eels can sense changes in Earth’s magnetic field to find those highways in a featureless expanse of ocean — even if it means swimming away from their ultimate destination at first, researchers report in the April 13 Current Biology. European eels (Anguilla anguilla) mate and lay eggs in the salty waters of the Sargasso Sea, a seaweed-rich region in the North Atlantic Ocean. But the fish spend most of their adult lives living in freshwater rivers and estuaries in Europe and North Africa. Exactly how eels make their journey from seawater to freshwater has baffled scientists for more than a century, says Nathan Putman, a biologist with the National Oceanic and Atmospheric Administration in Miami. The critters are hard to track. “They’re elusive,” says study coauthor Lewis Naisbett-Jones, a biologist now at the University of North Carolina at Chapel Hill. “They migrate at night and at depth. The only reason we know they spawn in the Sargasso Sea is because that’s where the smallest larvae have been collected.” |© Society for Science & the Public 2000 - 2017.

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 23492 - Posted: 04.14.2017

David Cyranoski For decades, scientists have wondered how animals can navigate huge distances using the weak signals of Earth’s magnetic field. So, interest was piqued in 2015 when two teams released papers in quick succession describing the functions of a protein found in animals that seemed to sense magnetic fields. But the claims have proved controversial, and questions have been piling up. The basic science behind the discovery was reported by Xie Can, a biophysicist at Peking University in Beijing, and his colleagues. In a paper in Nature Materials1, they claimed that a protein in animal cells forms a structure that responds to magnetic fields, and so might help in navigation. In the same year, a group led by Zhang Sheng-jia, then at Tsinghua University in Beijing, had published a paper in Science Bulletin2 reporting that the same protein could offer a powerful means of controlling brain cells. An academic battle has long raged between Xie and Zhang, but mounting evidence has cast doubt on both of their discoveries. Several researchers have challenged Xie’s claims that the protein reacts to magnetic fields. And last month, Xie co-authored a paper in Frontiers in Neural Circuits3 disputing Zhang’s work on the protein’s potential to magnetically control cells. This has all given rise to serious questions about the role of the molecule at the centre of the dispute. In their 2015 paper1, Xie and his colleagues reported that a protein called IscA1 forms a complex with another protein, Cry4, that explains how organisms pick up magnetic cues. The study found that this complex incorporates iron atoms, which gives it magnetic properties, and has a rod-like shape that aligns with an applied magnetic field. © 2017 Macmillan Publishers Limited

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 23452 - Posted: 04.05.2017

By Catherine Offord In the early 20th century, Danish biologist Johannes Schmidt solved a puzzle that had confounded European fisherman for generations. Freshwater eels—popular for centuries on menus across northern Europe—were abundant in rivers and creeks, but only as adults, never as babies. So where were they coming from? In 1922, after nearly two decades of research, Schmidt published the answer: the Sargasso Sea, the center of a massive, swirling gyre in the North Atlantic Ocean. Now regarded as some of the world’s most impressive animal migrators, European eels (Anguilla anguilla) journey westward across the Atlantic to spawning sites in the Sargasso; their eggs hatch into larvae that are carried back across the ocean by the Gulf Stream, arriving two or three years later to repopulate European waterways. For decades, researchers have assumed that adults made the journey in one short and rapid migration, leaving European coastlines in autumn and arriving in the Sargasso Sea, ready to spawn, the following spring. But this assumption rests on surprisingly little evidence, says behavioral ecologist David Righton of the UK Centre for Environment, Fisheries, and Aquaculture Science. “Since Johannes Schmidt identified this spawning area in the Sargasso Sea, people have been wondering about that great journey and trying to figure out how to follow the eels,” says Righton, whose work on epic marine migrations includes appropriately titled projects such as CODYSSEY and EELIAD. “But the technology hasn’t been available. . . . They just slip away into the darkness, really, in autumn, and no one knows what happens to them.” © 1986-2017 The Scientist

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 23116 - Posted: 01.18.2017

By Ben Andrew Henry Traveling from the forests and fields of Europe to the grasslands south of the Sahara desert is a monumental trip for anyone, and especially for a diminutive insect. Yet every year, populations of the painted lady (Vanessa cardui) butterfly make that journey over the course of several generations. The logistics of this migratory feat had been speculated for some time, but never fully understood, in part because of the difficulty of tracking the tiny insects across long distances. In a study published October 4 in Biology Letters, researchers reported having measured the isotopic composition of butterfly wings in Europe and south of the Sahara. Since the fraction of heavy hydrogen isotopes in the environment varies geographically, the team used its analysis to identify the origins of butterflies captured, confirming that groups of butterflies in the Sahara did originate in Europe. The butterflies do not linger in Africa long. They most likely make their trip, the authors suggested, to take advantage of the burst of productivity in the tropical savannah that follows the rainy season—and to breed the generation that will start the trip back. Europe’s freshwater eels (Anguilla anguilla) live out their days in rivers and streams, but they never spawn there. Massive catches of larval eels in the Sargasso Sea tipped researchers off a century ago that eels must spawn in the swirling mid-Atlantic gyre of free-floating seaweed and then migrate to Europe. Eels leave their homes in the late fall, but other than that, the details of their journey have been a mystery. © 1986-2016 The Scientist

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 23029 - Posted: 12.28.2016

By CHRIS BUCKLEY BEIJING — When Flappy McFlapperson and Skybomb Bolt sprang into the sky for their annual migration from wetlands near Beijing, nobody was sure where the two cuckoos were going. They and three other cuckoos had been tagged with sensors to follow them from northern China. But to where? “These birds are not known to be great fliers,” said Terry Townshend, a British amateur bird watcher living in the Chinese capital who helped organize the Beijing Cuckoo Project to track the birds. “Migration is incredibly perilous for birds, and many perish on these journeys.” The answer to the mystery — unfolding in passages recorded by satellite for more than five months — has been a humbling revelation even to many experts. The birds’ journeys have so far covered thousands of miles, across a total of a dozen countries and an ocean. The “common cuckoo,” as the species is called, turns out to be capable of exhilarating odysseys. “It’s impossible not to feel an emotional response,” said Chris Hewson, an ecologist with the British Trust for Ornithology in Thetford, England, who has helped run the tracking project. “There’s something special about feeling connected to one small bird flying across the ocean or desert.” But to follow a cuckoo, you must first seduce it. The common cuckoo is by reputation a cynical freeloader. Mothers outsource parenting by laying their eggs in the nests of smaller birds, and the birds live on grubs, caterpillars and similar soft morsels. British and Chinese bird groups decided to study two cuckoo subspecies found near Beijing, because their winter getaways were a puzzle. In an online poll for the project, nearly half the respondents guessed they went somewhere in Southeast Asia. © 2016 The New York Times Company

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 8: Hormones and Sex
Link ID: 22863 - Posted: 11.14.2016

James Gorman When the leader of a flock goes the wrong way, what will the flock do? With human beings, nobody can be sure. But with homing pigeons, the answer is that they find their way home anyway. Either the lead pigeon recognizes that it has no clue and falls back into the flock, letting birds that know where they are going take over, or the flock collectively decides that the direction that it is taking just doesn’t feel right, and it doesn’t follow. Several European scientists report these findings in a stirring report in Biology Letters titled, “Misinformed Leaders Lose Influence Over Pigeon Flocks.” Isobel Watts, a doctoral student in zoology at Oxford, conducted the study with her advisers, Theresa Burt de Perera and Dora Biro, and with the participation of Mate Nagy, a statistical physicist from Hungary, who is affiliated with several institutions, including Oxford and the Hungarian Academy of Sciences. Dr. Biro, who studies social behavior in primates as well as pigeons, said that the common questions that ran through her work were “about group living and what types of challenges and opportunities it brings.” She and her colleagues at Oxford have pioneered a method of studying flock behavior that uses very-fine-resolution GPS units, which the birds wear in pigeon-size backpacks. The devices record a detailed position for each bird a number of times a second. Researchers in Budapest and Oxford developed software to analyze small movements and responses of every bird in a flock. With this method, the scientists can identify which pigeons are leading the way. They can build a picture of how each bird responds to changes in the flight of other birds. © 2016 The New York Times Company

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 14: Attention and Higher Cognition
Link ID: 22696 - Posted: 09.26.2016