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ramonmercado Psycho Punk
Joined: 19 Aug 2003 Total posts: 17933 Location: Dublin Gender: Male |
 Posted: 01-02-2012 16:48 Post subject: A roundup of recent studies in behavior research |
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| Quote: | Behavior Brief
A roundup of recent studies in behavior research
http://the-scientist.com/2012/01/31/behavior-brief-15/
By Hannah Waters | January 31, 2012
FLICKR, FILEDUMP
Cannibalism: a safe bet?
Only around 30 percent of male orb web spiders (Argiope bruennichi) survive their first act of mating because they are devoured by their mates. But new research published in Animal Behaviour suggests that it may be worth it for the boost in offspring health and survival.
In a mating experiment, female orb spiders were allowed to mate with one, two, or three males—to test if multiple mates boost offspring health—and half of each group was allowed to eat their mate during and after sex. Mating frequency had no effect on the health of offspring. However, all females who consumed their lover after copulation had bigger clutches with heavier eggs, both indicators of health and likelihood of survival.
The results may explain why such cannibalistic behavior evolved, and why males sacrifice themselves rather than pursue additional matings. “Sexual cannibalism may increase male reproductive success and may be very beneficial in a species with a high paternity insurance and a low rate of polyandry”—multiple mating by the female, lead author Klaas Welke from the University of Hamburg told LiveScience.
Fish mimics mimic octopus
The mimic octopus bears that name for a reason: the brown-and-white-striped cephalopod is an expert at imitating diverse sea life, including flounder, lionfish, and sea snakes. Reporting in Coral Reefs, researcher Godehard Kopp from the University of Gottingen described the case of a jawfish taking advantage of the octopus’s expertise. Kopp was diving off the coast of Indonesia filming the octopus when he noticed something strange: a tiny striped fish camouflaged among the arms of the master camouflager itself! However, because of the geographical differences of the two species, the authors wrote, “we think this is a case of opportunistic rather than obligate mimicry.”
Hot nests, smarter lizards
Eastern three-lined skink
WIKIMEDIA COMMONS, ONESLAND
Nest temperature is known to alter many features of reptiles, affecting nutrient absorption in the egg and the speed and size of the resulting offspring. Now, research published in Biology Letters adds learning to the list.
Researchers from the University of Sydney raised two nests of skinks—one warmer, one cooler—then tested the lizards on their ability to hide from predators. The setup was simple: in the back of their tank, they placed a hiding spot with two entrances, one of which was blocked by clear plastic. After some learning drills, the researchers startled the skinks with a touch of the tail, and counted how many times the lizard went for the correct entrance and how long it took.
The skinks that developed in the warmer nest reigned supreme at the learning test. Potentially, this means that, with a warming climate, these skinks will become harder for predators to catch. However, lead author Joshua Amiel warned in Cosmos Magazine that this may not apply to all lizards and that, for some species in cooler habitats, cold nests may be better.
Jumping spiders focus on prey
Adanson's jumping spider
SCIENCE/AAAS
Jumping spiders have the rare ability to pinpoint and land upon prey from a far distance—but how? One answer lies in their vision, according to new research published in Science. Two of the jumping spider’s eight eyes are dominant and larger, and both of these have four retinal cell layers, each of which focus on different wavelengths of light. Two of these layers are sensitive to green light: in one, green light is always in focus and, in the other, green light is never in focus.
In an elegant experiment, Japanese researchers presented Adanson’s jumping spiders with fruit fly prey under either green or red light. Under the green light, the flies were successful at catching prey, but under the red light, their depth perception was off. This is because the flies need to compare the in- and out-of-focus images under green light to judge depth. When only red light was available, they couldn’t pinpoint the distance to their prey.
“So the spider seems to capture a sharp image and a blurry image and compare the information to estimate the distance of an object,” author Mitsumasa Koyanagi told the New York Times.
Plant consumes underground worms
In 2000, scientists discovered a rare plant species (Philcoxia minensis) in Brazil that, strangely enough, had most of its sticky leaves growing underground. Clearly those leaves didn’t have a photosynthetic purpose; why would such foliage exist?
The researchers noticed that small worms were often found stuck to the leaves and, suspecting carnivory, fed these nematodes nitrogen-15-laden food as a biomarker. After placing the traceable worms in the soil near Philocoxia’s sticky leaves, the scientists were able to detect the heavy isotope of nitrogen in the plant’s tissues. Furthermore, Philocoxia showed enzymatic activity similar to other carnivorous plants, suggesting that the worms did not decompose and release the nitrogen-15 passively.
The results, published in The Proceedings of the National Academy of Sciences, suggest that “carnivory may have evolved independently more times in plants than previously thought,” lead author Rafael Oliveira from Brazil’s Universidade Estadual de Campinas told LiveScience. |
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| ramonmercado Psycho Punk
Joined: 19 Aug 2003 Total posts: 17933 Location: Dublin Gender: Male |
| Posted: 22-02-2012 15:03 Post subject: |
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| Quote: | Behavior Brief
http://the-scientist.com/2012/02/21/behavior-brief-16/
A round-up of recent discoveries in behavior research
By Megan Scudellari | February 21, 2012
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Bluetongue lizard
SCOTT MAXWORTHY, FLICKR
Dangerous snack
Poisonous invasive species don’t deter the hungry Australian bluetongue lizard. A new paper in the American Naturalist found that the native lizards that eat toxic mother-of-millions plants are largely resistant to the toxins of the invasive cane toad, which has wreaked havoc on Australia’s ecosystems since being purposefully introduced in 1935 in an attempt to control the native cane beetle, which damages sugar cane crops. Both the plant and toads produce a toxin called bufadienolide. When injected with a non-lethal dose of bufadienolide, bluetongues from areas of Australia without the toxic plant swam 50 percent slower than normal, while bluetongues from areas with the plants swam only 20 percent slower, demonstrating a resistance to the poison.
The researchers hope that resistance will lessen the impact of another potential invader with a similar toxin, the black-spined toad, ScienceNOW reported. The toad has already invaded numerous countries in Asia, and might soon make the leap to Australia.
Ultrasonic cryptography
Philippine tarsiers may be small, but they have a superhero sense of hearing. The little primates, often no bigger than a human hand, communicate using ultrasonic sounds, according to a study published earlier this month in Biology Letters. Only a few other mammals, including cetaceans, domestic cats, and some bats and rodents, send and receive vocal ultrasound signals. The tarsiers’ squeaky calls, well above the vocal range of any known monkey or ape, may keep predators like birds from listening in on their conversations, reported ScienceNOW. The ability to hear the ultrasonic sounds may also help tarsiers zoom in on their prey—small insects that also communicate using ultrasonic frequencies.
Researchers tested the primates for ultrasonic abilities after casual observations that tarsiers occasionally opened their mouths as if to shout, but no sound humans can hear came out. “Philippine tarsiers have often been described as quiet,” co-author Marissa Ramsier, an anthropologist at Humboldt State University in California, told ScienceNOW. But “they’re screaming and talking away, and we just didn’t know it.”
Tarsiers ultrasonic vocalization, slowed
down by a factor of 15
Song of the dead
A 165-million-year-old cricket song has been resurrected. Researchers at China’s Capital Normal University compared the well-preserved wing structures of fossil Archaboilus musicus, a Jurassic ancestor of modern crickets, to contemporary cricket wings, Wired reported, and from that reconstructed what the song might sound like. The low-frequency, high-pitched song may have helped the ancient crickets communicate in the leafy, fern-filled Jurassic forest in which they lived, the authors suggested in a recent PNAS paper.
Bonobo takes up cooking
Kanzi
COURTESY OF THE GREAT APE TRUST
Kanzi, a famous bonobo at the Great Ape Trust in Des Moines, Iowa, understands 3,000 spoken words and can communicate 500 words by pointing to symbols. Now he’s added another impressive skill to his resume—cooking a hamburger. It is the first time a non-human primate has demonstrated the ability to cook food, the Daily Mail reported.
According to his keepers, Kanzi has always been fascinated by campfires and was encouraged, though never instructed, to build them. In a video taken by the Great Ape Trust, Kanzi builds a fire, toasts marshmallows, and grills hamburgers. Finally, like a good camper, he pours water over the fire to put out the flames when finished. See a video of Kanzi in action.
Hot finger
Note the aye-aye's long twig-like third finger
CENZ, FLICKR
The Madagascar aye-aye, the largest nocturnal primate, is recognizable for its strange, twig-like middle finger, an extra-long appendage packed with nerve endings and used to tap tree trunks to find beetle larvae. It turns out the aye-aye is able to regulate the temperature of that single digit, according to a paper in the International Journal of Primatology. Researchers at Dartmouth College in New Hampshire used infrared imaging to examine the finger, and found that it remains cool when not in use but warms by up to 6°C when the animal uses it to forage.
Because of its specialist sense receptors, the finger is costly in terms of energy, co-author Gillian Moritz told BBC Nature. “Like any delicate instrument, it is probably best deactivated when not in use,” she said. How the lemur controls the heating of a single digit remains unknown.
Friendly seas
Wildlife videos typically show species interacting, but usually one species is attacking another. In a heartwarming twist on this typical scenario, researchers recently recorded two separate instances of bottlenose dolphins “riding” humpback whales in Hawaii: the whales lifted the dolphins up and out of the water, and the dolphins slid back down into the surf. Both species seemed to cooperate, with no aggression, in the rarely observed social activity. The interaction was described in Aquatic Mammals and a video of the encounter was recently on display at the American Museum of Natural History.
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| ramonmercado Psycho Punk
Joined: 19 Aug 2003 Total posts: 17933 Location: Dublin Gender: Male |
| Posted: 23-03-2012 21:45 Post subject: |
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| Quote: | Behavior Brief
http://the-scientist.com/2012/03/21/behavior-brief-17/
A round-up of recent discoveries in behavior research
By Megan Scudellari | March 21, 2012
Copepod
LEO PAPANDREOU, FLICKR
Flying plankton
Copepods, a small type of plankton that drift in the sea, live close to the ocean’s surface where they are conspicuous targets for hungry fish below. But these little crustaceans have a surprising evasive maneuver: they jump out of the water and into the air to escape predators, according to a new paper in the Proceedings of the Royal Society B. Researchers at the University of Texas at Austin and colleagues used high-speed video recordings to track copepods, and found that those that break the water surface travel significantly farther than those attempting to escape underwater. This “flying” evasion helped copepods to more successfully evade predators.
Strongest bite
The saltwater crocodile has the highest bite force of any living animal.
COURTESY OF FLORIDA STATE UNIVERSITY
Who would win a fight—a crocodile or Tyrannosaurus rex? According to a report in a recent issue of Biology Letters, the T. rex bit down with as much as 12,800 pounds of pressure on a single back tooth. That could easily take out a modern crocodile, the strongest biter among living animals, which has a bite force of 3,700 pounds. But the T. rex is no match for the largest extinct crocodilians, which generated bite forces in excess of 23,000 pounds, researchers from Florida State University reported last week (March 14) in PLoS One. This powerful chomp may be why crocodilians have remained kings of the water-land interface for over 85 million years.
Penguin victory dance
Little penguin, Eudyptula minor
FIR0002, WIKIMEDIA COMMONS
After a fight, territorial male blue penguins, Eudyptula minor, aren’t afraid to boast about their win. These little penguins perform a loud victory dance, waving their flippers and braying like donkeys. Scientists at the University of Waikato in Hamilton, New Zealand, wondered how all those victory displays affected nearby penguins, ScienceNOW reported.
Using fake eggs to measure the heart rate levels of brooding penguins in their burrows, the researchers found that both male and female penguins were stressed while listening to fight recordings. Additionally, males were more stressed if a winner approached their burrows, and were more likely to challenge an approaching loser. The research suggests that male blue penguins are signaling to bystanders not to mess with them.
Brave bees
Honeybee scouts may be little, but they are bold. Researchers at the University of Illinois at Urbana–Champaign investigated why some honeybees scout for food and new nesting sites while others stay cautiously at home. The team compared the gene expression profiles of the brains of adventurous honeybees to the brains of bees that stay close to the hive. They found that the scouting bees had dramatic gene expression differences in catecholamine, glutamate, and GABA signaling levels. Treating the scouts with glutamate increased their bold behavior, while blocking dopamine decreased it, according to the research published in Science.
The results raise the possibility that there’s a genetic toolkit for this kind of novelty-seeking behavior in vertebrate species, including humans, author Gene Robinson told ScienceNOW.
Sawfish sense and impale prey
Sawfish are famous for their long toothy snouts, and now scientists have figured out what exactly what those saw-like snouts are used for. In the recent study in Current Biology, researchers at the University of Queensland report that the fish use their snouts both as a sensory organ and a hunting weapon. Filmed on hidden cameras, captured sawfish used their saws to tear into already dead fish. “I was surprised to see how skilled sawfish are with their saw,” author Barbara Wueringer said in a press release. “They use their saw to impale prey on the rostral teeth by producing several lateral swipes per second.”
The sawfish also used their snouts, which are covered with thousands of electroreceptors, to respond to weak electrical fields that mimicked live prey. But, the films revealed, sawfish do not use their snouts to rifle through the sand, as some related species do, BBC News reported.
Goats with accents?
Pygmy goat kids
PICBOT, FLICKR
Like humans, elephants, and dolphins, goats have the ability to modify the sound of their voice according to their social environments, according to a new study in Animal Behavior. Researchers at Queen Mary University of London studied the calls of four groups of pygmy goats, which live in complex social groups. They found that genetically related kids produced similar calls, which was not surprising, but the calls of kids raised in the same social groups were also similar to each other, and became more similar as the goats grew older.
“This suggests that goat kids modify their calls according their social surroundings, developing similar ‘accents,’” co-author Elodie Briefer said in a press release. Vocal plasticity in goats could suggest a possible early pathway in the evolution of vocal communication, the authors noted. |
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| ramonmercado Psycho Punk
Joined: 19 Aug 2003 Total posts: 17933 Location: Dublin Gender: Male |
| Posted: 19-06-2012 22:53 Post subject: |
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| Quote: | Behavior Brief
A round-up of recent discoveries in behavior research
http://the-scientist.com/2012/06/15/behavior-brief-19/
By Hayley Dunning | June 15, 2012
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A gecko flips under a ledge.
POLYPEDAL LAB, JEAN-MICHEL MONGEAU, ARDIAN JUSUFI AND PAULINE JENNINGS
Quick escape
Cockroaches and geckos can’t always outrun an angry homeowner, but researchers have discovered they do have a few ninja-like tricks to disappear in the heat of danger. Racing towards the end of a ledge, cockroaches and geckos don’t slow down, but anchor themselves to the edge and swing underneath at high speed, according to a study published on June 6 in PLoS ONE. Cockroaches use claws on their back legs to facilitate the pendulum swing; flat-tailed house geckos make added use of the sticky hairs on their feet that allow them to climb up walls and windows.
The team at the University of California, Berkeley, discovered the trick using high-speed cameras to slow down the speedy critters, who are thought to be more maneuverable due to their small scale. Their motion was then digitized and a model was created, allowing the researchers to design a small robot with the same capabilities. Their hope is to draw natural inspiration for nimble search-and-rescue robots.
Wired to run
We’re all endurance athletes at heart, according to a study published April 15 in the Journal of Experimental Biology, which identified a chemical underpinning of “runner’s high.” Researchers at the University of Arizona and Eckerd College put naturally athletic humans and dogs on treadmills, as well as the more sedentary ferret, to test the effects of runner’s high between mammal species.
Blood samples taken before and after the humans and dogs had happily run on the treadmill revealed elevated levels of the endocannabinoid anandamide, which corresponded with positive emotional feelings reported by the human subject. The ferrets, on the other hand, showed no evidence of such a chemical high.
Endocannabinoids, so-named for the related active ingredient in cannabis, are neurotransmitters that signal the brain’s “reward centers.” The spike after running suggests natural selection worked to encourage high-intensity activities in certain mammals.
“The result of this anandamide-inspired motivation to run was the evolution of an ‘endurance athlete phenotype’,” co-author Greg Gerdeman said in a press release, which “played a major role in the survival and reproductive success of our Homo sapiens ancestors.”
Vampires prefer females for dinner
The Evarcha culicivora jumping spider.
UNIVERSITY OF CANTERBURY, XIMENA NELSON
Vampire jumping spiders distinguish the tastiest prey based on their antennae, according to a new study to be published on July 1 in the Journal of Experimental Biology. One species of jumping spider native to East Africa feeds indirectly on vertebrate blood—by catching mosquitoes that have just fed. Since male mosquitoes don’t consume blood, the spider gets a more nutritious meal from females.
To test which body parts enticed the spiders, researchers from the University of Canterbury in New Zealand created Frankenstein mosquitoes made of different body parts of dead males and females. While a blood-engorged abdomen was the biggest clue, when two blood-laden Frankenstein -bugs had different antennae, the spiders preferentially pounced on the one with the female head.
Seed-spitting mice
Plants can be picky about who gets to eat them. In the latest example from the Israeli desert, the sweet mignonette plant forces the spiny mouse to spit out its seeds while munching on the fruit by setting off a “mustard oil bomb,” according to new research published in Current Biology last week (June 14).
When a seed is chewed, enzymes are released that activate toxic substances in the fruit pulp, causing a hot mustard taste that the mice and other rodents spit out, along with the seed. When the American and Israeli research team deactivated the mustard bombs, the mice consumed 50 percent more seeds than when the bombs were active, suggesting the plant makes the mice very efficient seed-spreaders.
“It’s fascinating that these little mice are doing analytical chemistry,” biologist and co-author Denise Dearing said in a press release. “Assaying the fruit for toxic compounds and learning not to bite into the seed.”
Cute cannibalism?
Researchers looking for a radio-tagged female gray mouse lemur in Madagascar got a nasty surprise when they found her: a male of the same species was literally making a meal of her. This is the first documented case of cannibalism in non-human primates where the victim is an adult, according to the report published online May 23 in the American Journal of Primatology.
The cause of death of the female gray mouse lemur was unknown because the male had already chomped down her vital organs, but she was known to have been alive and active an hour before being discovered.
Examples of species that practice juvenile cannibalism include chimps, bonobos, and orangutans, and is thought to be motivated by food: get rid of an extra mouth and get some extra nutrition at the same time. But other than humans, no primate has ever previously been found to eat another adult. While one case isn’t necessarily indicative of the entire species, the finding raises intriguing questions about what primates are willing to supplement their diets with.
Gorilla baby talk
FLICKR CREATIVE COMMONS, MARIEKE IJSENDOORN-KUIJPERS
Gorillas communicate differently with their young than to other adults, much the same way humans do, according to a study published May 29 in the American Journal of Primatology. Instead of vocal signals, however, the team at the Max Planck Institute for Evolutionary Anthropology watched mother gorillas’ hand gestures and facial expressions for signs of baby talk. They found that the mothers used similar signals to those used in adult groups, such as a hand on the head to mean “stop it,” but used them far more frequently with youngsters.
Tactile gestures in general were more prevalent when Mom was talking to baby, and the researchers believe this is partly to help the youngsters learn to use the language of the group. The finding also hints that parent gorillas know that they have to communicate more carefully with infants who have fewer skills.
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| ramonmercado Psycho Punk
Joined: 19 Aug 2003 Total posts: 17933 Location: Dublin Gender: Male |
| Posted: 09-07-2012 22:35 Post subject: |
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| Quote: | Behavior Brief
http://the-scientist.com/2012/07/08/behavior-brief-20/
A round-up of recent discoveries in behavior research
By Hayley Dunning | July 8, 2012
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Osedax, “bone devourer” worms
GREG ROUSE, UC SAN DIEGO
An acid bone meal
Tiny worms that bore into whale bones use acid to get at the nutrients, according to new research presented at the Society for Experimental Biology annual conference in Salzberg, held last week (June 29 – July 2). The mysterious worms, discovered only 10 years ago, have no mouth, gut, or anus. Researchers discovered that symbiotic bacteria break down the ingested fats and oils, but how the worms could dig into bone was unclear. The new study identifies acid-secreting enzymes in the root-like regions of the worms that attach to the bone. The skin cells on the “roots” are long and protruding, with enlarged surface areas that help maximize the amount of acid secreted.
The group of worms, termed Osedax (Latin for “bone devourer”), was discovered by chance when researchers hunting for deep-sea clams came upon a rotting whale carcass and sampled the ecosystem that had formed around it. The worms have attracted a lot of attention for their odd living arrangements, where the males remain in a larval stage and reside inside the females.
Must diet and exercise
Dietary restriction may not be enough to prolong life, according to a new study published July 3 in Cell Metabolism that shows flies have to be active to reap the benefits of dieting. Dietary restriction is thought to elongate life through enhanced fat metabolism, especially in muscle tissues, which has previously been linked to increased spontaneous activity. The increased movement is thought to be an evolutionary adaption to encourage foraging, and has been observed in primates. However, it was not known whether the muscle movements were necessary to promote the life-extending benefits of eating less. In this study, fruit flies on the same calorie-restricted diet, but that were not able to move, didn’t live as long as their active counterparts.
According to the researchers, if the same holds true for humans, cutting back on food alone may not be the best strategy. It’s also important to remain active, and to do so, enough still needs to be eaten to avoid fatigue. The research also highlighted peptides that increase fat metabolism and spontaneous activity independent of dietary restriction, pointing to the potential for drugs that do the same.
Two-faced fish
Cuttlefish use a camouflage technique to deter potential competitors, splitting their skin pattern between a male side and a female side. The behavior, observed for the first time and reported last week (July 3) in Biology Letters, allows a male cuttlefish to court a female with his male-patterned side while throwing off other potential mates by showing them his female-patterned side.
Cuttlefish displaying dual patterns
CULUM BROWN, MACQUARIE UNIVERSITY
Cuttlefish change their patterns by shifting pigment-containing cells closer or further away from the surface of their skin. They were known to be able to show two patterns at once on different sides of their body, but when one researcher noticed in the lab’s aquarium that male fish were displaying a female pattern, he and colleagues combed through images of cuttlefish in the wild to look for patterns of behavior. In a group with one female and two males, the male closest to the female displayed the dual-gender pattern 39 percent of the time. Cuttlefish have one of the largest brain-to-body size ratios of any invertebrate, and the study’s authors believe the behavior is a mark of their complex social intelligence.
Sluggish sharks sneak up on seals
The Greenland shark, the ocean’s slowest fish for its size, spends a lot of its time snoozing in deep, cold waters. While the remains of seals had been found in their stomachs, it was believed they simply ate the carcasses that floated down to the sea bed, but a new study published online last month (June  in the Journal of Experimental Marine Biology and Ecology found they actually do hunt live prey. While even at burst speed, the sharks only travel at 0.7 meters per second (1.6 mph), around 0.3 m/s slower than a swimming seal, they can sneak up on seals taking a nap. Seals often sleep in the water to avoid being caught by polar bears, but this leaves them vulnerable to the Greenland shark.
The Greenland shark was investigated as part of a project to find out what was eating all the seals off the coast of Svalbard, an island group in the Arctic. The sharks were an unlikely culprit, but shark expert Vincent Gallucci from the University of Washington explained to BBC News that a Greenland shark may not need “to get 100 percent of its mouth onto its prey” in order to eat it. They also use a sucking motion when eating, which may make it “a bit easier for a lie-in-wait ambush predator to consume prey that pass near its mouth,” said Gallucci.
The bird violin
The odd mating song of the male club-winged manakin is created by solid bones, an oddity in the bird kingdom. Most birds have slim, hollow humerus and ulna bones that help them to fly, but in the manakin, these bones are solid, and the ulna is covered in lumps and bumps, revealed a study published last month (June 13) in Biology Letters. Raising its wings over its back, the manakin can make a high-pitched peep, which the researchers think is made by special resonating feathers that are anchored in the ulna’s bumps. The solid bone then amplifies the sound by bouncing it throughout the feather.
Despite the extra weight, Makain birds are still able to fly, and the authors of the study conclude the benefit to sound production must be great. High-speed cameras reveal that to make its unusual song, the manakin bird rubs its wings together with intense vibration, around twice the speed of hummingbird wings.
Counting bears
Bears have been participants in the circus, but new research shows they can do more than just perform tricks—they are intelligent enough to count. Three American black bears were trained to pick between groups of dots that either had fewer or more dots than other groups. The dots in the groups were sometimes close together, sometimes further apart, and sometimes moving, but all three bears picked the right group significantly more than would be predicted by chance.The authors suggest this means the bears are not just estimating the magnitude of what they were being shown, which many animals can do, but actually doing something analogous to counting.
WIKIMEDIA COMMONS, EPIPELAGIC
The research, published June 3 in Animal Behavior, puts the bears’ performance on the same level as monkeys. Lead author Jennifer Vonk of Oakland University told the BBC that “people don’t generally understand them to be as intelligent as they probably are.” Despite having the largest relative brain size of any carnivore, the way they think is not well understood.
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| ramonmercado Psycho Punk
Joined: 19 Aug 2003 Total posts: 17933 Location: Dublin Gender: Male |
| Posted: 15-09-2012 22:53 Post subject: |
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Zombees, multi-talented stick insects, undertaker jays and more.
| Quote: | Behavior Brief
A round-up of recent discoveries in behavior research
http://the-scientist.com/2012/09/11/behavior-brief-23/
By Beth Marie Mole | September 11, 2012
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Conlephasma enigma
MARCO GOTTARDO, OSKAR CONLE
Twiggy enigma
A newly identified insect has the coloring of an exotic tropical bird, the defense mechanism of a skunk, and the look of tree debris. Researchers collected the otherworldly stick insect a few years ago from a remote mountain on the Philippine island of Mindoro, and found that it is so unique that it deserves its own genus.
“We were baffled,” Marco Gottardo, a PhD student at the University of Siena, Italy, told the BBC. “It looked so different from any other known stick insect in the world that we immediately realized it was something very special.”
The twiggy creature, Conlephasma enigma, has a dazzling blue-green head and fiery orange and yellow body. When provoked, it releases a foul smelling spray from glands on its head. Also unique, the new stick insect “is wingless, with a stout body and rather short legs,” which may be an adaptation to the short vegetation of the mountainous rainforest it calls home, Gottardo told the BBC. He and colleagues reported their findings published online last month (August 22) in the journal Comptes Rendus Biologies.
Funerals are for the birds
A Western Scrub Jay
WIKIMEDIA COMMONS, NOËL ZIA LEE
When a western scrub jay dies, its fellow birds gather around for a cacophonous ceremony. But their deafening display isn’t an emotional tribute to the fallen; it’s a sign of alarm, according to a team of animal behavior scientists at the University of California, Davis.
The very sight of the dead is enough to “induce alarm-calling and subsequent risk-reducing behavioral modification in western scrub-jays,” lead author Teresa Iglesias wrote in an article published online last month (August 27) in Animal Behaviour.
Like all animals, the brilliant blue birds face risks, which they mitigate by spotting signs of danger, she wrote in the article. Without sleuth work to discover the cause of death, a corpse indicates a potential hazard. When the research team presented the birds with a fake predator—a stuffed great horned owl—the western scrub jays created a similar commotion. Regardless of whether the ruckus is from a death or a predator sighting, jays will avoid the hazardous site for at least 24 hours afterward.
Color-coded food
In the dark abyss of the seafloor, some crustaceans can see dim flashes of blue and ultraviolet (UV) light, which may help them discern what’s food and what’s not.
Bioluminescent plankton swirled by an eddy
WIKIMEDIA COMMONS, NASA'S EARTH OBSERVATORY
A team of deep-sea diving researchers, led by Duke University’s Sönke Johnsen, sunk down to the seabed around the Bahamas, where they found themselves surrounded by small bursts of light, spilling out of bioluminescent plankton colliding with corals and rocks. Though bioluminescence is common higher in the water column, the researchers found the ability in only 20 percent of the species they encountered in the ocean’s depths.
Using the robotic arms of the submersible vehicle, they collected a variety of glowing creatures, and measured their light spectra, which ranged from the blue-green spectra (plankton) to the green spectra (corals).They also gathered up and tested crustaceans, and found that they some could perceive blue and UV lights, which may help them identify their food, Johnsen said.
“Color vision works by having 2 channels,” Johnsen said in a press release. By combining input from the blue light photoreceptors and the UV light photoreceptors, crustaceans might be able to discern different colors within the blue-green spectrum, helping them pin-point plankton prey among inedible coral, he explained. The research will appear in two articles in the October 1 issue of The Journal of Experimental Biology.
“The idea that they may be using it to color-code their food is exciting, but of course still in the hypothesis stage,” Johnsen told BBC News.
Friendly smells
Whether a fellow hyena is friend or foe may depend on the types of microbes they carry, according to an article published August 30 in Scientific Reports. Michigan State University researchers identified bacterial symbionts housed in the hyenas’ scent pouch, located in their rumps, and found that each social group had a unique community of bacteria that produced their signature smell.
Spotted Hyena cubs
WIKIMEDIA COMMONS, NEW JERSEY BIRDS
“The complex social lives of these animals may ultimately be reliant upon their unheralded symbiotic microbial communities,” lead author Kevin Theis, a postdoctoral researcher at Michigan State, said in a university press release.
In addition to being a sour-smelling calling card, the odors may help social groups stake their claim on turf. “Multiple members of the clan could more efficiently carry out the job and mark more territory,” Theis said in the release, which could also help reduce clashes between neighboring groups.
Tracking zombees
Following last year’s discovery that a fly parasite can turn healthy bees into tail-spinning zombie bees, researchers at San Francisco State University (SFSU) are out to track infected flies and determine their effects on the rest of the hive.
Honey Bees
WIKIMEDIA COMMONS, KADRI PUNA
They’ve attached tiny radio trackers—the size of a piece of glitter—to the thorax of infected bees and will monitor the insects’ behaviors to understand the effects of the parasite. The researchers are also monitoring artificial hive entrances and exits, using a dual laser reader. The work will help determine “if parasitized foragers are the recipients of aggression by other workers, for example if they’re expelled from the hive, or if parasitized foragers behave in ways that disrupt hive productivity,” said SFSU biologist Andrew Zink in a news release.
But Zink and his colleagues can’t track all of the infected bees alone. To help, they’ve enlisted citizen scientists who can log onto their website, zombeewatch.org, to report and keep updated on zombie bee-related news.
Read about other strange parasite-induced behaviors in our January feature, “Animal Mind Control.” |
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| ramonmercado Psycho Punk
Joined: 19 Aug 2003 Total posts: 17933 Location: Dublin Gender: Male |
| Posted: 10-02-2013 00:50 Post subject: |
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| Quote: | Behavior Brief
A round-up of recent discoveries in behavior research
http://www.the-scientist.com/?articles.view/articleNo/34287/title/Behavior-Brief/
By Kate Yandell | February 6, 2013
Aphids land on their feet
Cats aren’t the only animals to land on their feet after a fall. When pea aphids fall—a trick they use to avoid predators—they rotate in mid-air so they can land upright on plants and hold on with their sticky feet, according to a study published in Current Biology this week (February 4).
The aphids don’t have any special structures to right themselves. Rather, the wingless creatures rotate their bodies into the proper orientation by adopting just the right posture—with antennae forward and back legs angled up and back—such that they are only aerodynamically stable when upright. In this position, the air naturally flips them over.
When dropped from a height of 20 centimeters (7.9 inches), the aphids landed on their feet 95 percent of the time, the researchers found. However, dead aphids only landed on their feet 52 percent of the time, showing that the posture was actively maintained and important for a successful landing.
Stargazing dung beetles
CURRENT BIOLOGY, DACKE ET AL.
Like sailors in the Age of Exploration, dung beetles use the stars to navigate the night. Male dung beetles amass giant balls of dung to woo females, which lay their eggs in the nutritious dung. Males that take a meandering path with their dung balls are liable to get robbed by other dung beetles, while males that travel in a straight line are more likely to get to their destinations safely. A paper published in Current Biology last month (January 24) found that, to keep form getting lost in the dark, the beetles orient themselves using the Milky Way.
Researchers discovered the beetles’ celestial talents while studying how they used the moon to navigate. One moonless night, they noticed that the beetles were still transporting their dung in relatively straight lines. “Even without the moon—just with the stars—they were still able to navigate,” coauthor Eric Warrant, a zoologist at Lund University in Switzerland, told ScienceNOW. “We were just flabbergasted.”
The researchers confirmed their findings in a planetarium, where the beetles successfully navigated by the stars projected on the ceiling—either the entire night sky or just the Milky Way—but did poorly when there were few stars or when their view of the sky was obscured by pieces of cardboard on their backs.
An unmistakable bite
WIKIMEDIA, NOAA OBSERVER PROJECT
Divers have found evidence that great white sharks aren't at the top of the food chain after all. In a paper published in the January issue of Pacific Science, authors describe evidence that the small cookie-cutter shark, just one-tenth the size of a great white, is snacking on the flesh of its much larger cousin.
In 2010, a diver who found a great white shark off the coast of Mexico with a round hole and crescent-shaped bite on its head. “I don’t know of any other animal that leaves a bite like that,” the diver, named Gerardo del Villar, told the National Geographic blog Not Exactly Rocket Science (authored by The Scientist correspondent Ed Yong). Del Villar had seen other sharks with similarly odd marks and this time snapped a photo and sent it to scientists at the Florida Museum of Natural History.
The scientists confirmed that the bite was characteristic of the cookie-cutter shark. The cookie-cutter shark is just one-tenth of the size of the great white. It latches onto its prey with its round mouth and twists, like a cookie-cutter in dough, scooping out a tasty chunk of flesh and leaving its victim with a hole in its side. Even though the wounds are small, the damage can be dangerous and even fatal. The cookie-cutter shark has chomped on whales, dolphins, humans, and even a nuclear submarine.
Baboon dads help out
WIKIMEDIA, D. GORDON E. ROBERTS
Unlike most promiscuous mammals, baboon fathers appear to mentor their own young, according to a paper published Behavioural Ecology on November 1. And that guidance from dad helps the young baboons thrive.
Baboons are promiscuous and it is not always clear which baboon fathered which child. In promiscuous species, absentee fathers are common. “Paternal care is usually observed in species where paternity certainly is high, [such as] in monogamous species,” behavioral ecologist Elise Huchard of the University of Cambridge told BBC News.
Observing young chacma baboons in Namibia, however, Huchard and her colleagues found that the young baboons were tagging along with their genetic fathers—determined by DNA testing—especially when their mothers were absent and when it was time to find food. And with their fathers, the young baboons did better at foraging. “It was exciting to find that in this population, males actually care for their own offspring,” Huchard told the BBC, “which suggests that they are able to discriminate their own offspring and that such bonds do represent paternal care.”
Compassionate cetaceans
FLICKR, MIKE BAIRD
Dolphins have been known to try to help calves in need, pushing them to the surface of the water or biting them to stimulate them. But a recent paper documents a more unusual display of supportive care: a group of long-beaked common dolphins trying to save a dying adult member of their species.
Scientists in a vessel off the coast of Korea observed the dolphins coming together to form a raft-like shape with their bodies, pushing the ailing dolphin to the water’s surface. One dolphin even propped up the sick dolphin’s head with its beak. Unfortunately, the dolphin died after a few minutes, but the other dolphins continued to support it, according to the paper published in Marine Mammal Science last month (January 1.
In another show of surprising supportiveness, a group of sperm whales adopted an adult bottlenose dolphin with a spinal deformation. Researchers discovered the dolphin while observing sperm whales in the North Atlantic and will publish their findings in the journal Aquatic Mammals.
“Sometimes some individuals can be picked on,” Alexander Wilson, a biologist at the Leibniz Institute of Freshwater Ecology and Inland Fisheries in Berlin who was with the group that spotted the dolphin, told ScienceNOW. “It might be that this individual didn't fit in, so to speak, with its original group.” As for why the sperm whales adopted the misfit, they could have benefited from social interaction with the dolphin, the authors noted. |
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| ramonmercado Psycho Punk
Joined: 19 Aug 2003 Total posts: 17933 Location: Dublin Gender: Male |
| Posted: 24-05-2013 20:56 Post subject: |
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| Quote: | Behavior Brief
A round-up of recent discoveries in behavior research
By Dan Cossins | May 23, 2013
http://www.the-scientist.com/?articles.view/articleNo/35705/title/Behavior-Brief/
Vervet monkeys choose between trays filled with corn dyed different colors.
ERICA VAN WAAL
Signs of culture in monkeys and whales
Humans aren’t the only animals with culture, or the ability to collectively transmit and adopt behaviors among a group. Indeed, some level of cultural transmission and learning has been identified in several other species. But two studies published last month (26 April) in Science provide the strongest evidence yet, showing that vervet monkeys and humpback whales learn new behaviors from each other in much the same way as humans pick up the latest trend.
In the first study, researchers from the University of St. Andrews in Scotland created two distinct “cultures” among a group of more than 100 wild vervet monkeys (Chlorocebus pygerythrus) in South Africa: one set was trained to eat only corn dyed blue; another to eat only pink corn. Several months later, when 27 infants from the group were offered the choice, all but 2 of them chose the color that their mother preferred. In addition, 7 of 10 adult males that had migrated from one set to the other immediately took up the color of their new group. The results suggest that cultural conformity could shape behavior in wild vervet monkeys.
In the second study, a different team from St. Andrews mined observational data on humpback whales (Megaptera novaeangliae) in Massachusetts Bay collected over 27 years to see if lobtail feeding—a technique in which the whales strike the water with their tales, most likely to confuse and herd prey fish together—was spreading, as anecdotes suggested. The researchers found that since 1980, when the feeding behavior was first spotted, it has spread to 37 percent of the population. What’s more, almost 90 percent of the whales that adopted the technique appeared to have learned it by copying a nearby whale that was already using the trick.
Carel van Schaik, a primatologist at the University of Zurich in Switzerland, told ScienceNOW that the publication of these two papers “marks the moment where we can finally move on to discuss the implications of culture in animals,” rather than debating whether or not cultural transmission occurs in animals.
The smaller sand shark embryo (left) was retrieved from the throat of the larger one.
DEMIAN CHAPMAN
It’s a shark-eat-shark womb
Female sand tiger sharks (Carcharias taurus) often carry eggs fertilized by several different fathers in their 2 uteri. Only one shark emerges from each womb, however, each of which has grown big and strong by eating all of the other embryos. This process, known as “embryonic cannibalism,” was previously documented, but in a report out earlier this month (May 1) in Biology Letters, researchers have revealed that it plays a role in deciding the reproductive success of the males.
“For most species, we think of sexual selection as ending when males fertilize eggs, because once the male’s fertilized eggs he’s won . . .” Demian Chapman of Stony Brook University, who led the study, told The Washington Post. “This is demonstrating that embryonic cannibalism is actually whittling down the number of males producing offspring.”
Chapman and colleagues studied 15 pregnant sand tiger sharks that died after being caught in protective nets off beaches in South Africa. DNA profiling showed that the 5 sharks that had died in the early stages of pregnancy carried had eggs that had been fertilized by several different males. But both pups that remained in the twin uteri of the 10 sharks that were in the later stages of pregnancy were fathered by the same male.
Exactly what determines which of the males’ offspring makes it out of the uteri alive is not clear. Perhaps the embryos fertilized first have a headstart that helps win the bloody battle in the womb. However, it is also possible that some “fitter” males carry genetic material that produces faster-developing embryos that can overtake—and then devour—even those embryos fertilized before them.
Harvester ants wait for interaction with returning foragers to decide whether to leave the nest.
KATIE DEKTAR
Restrained ant colonies do better
Harvester ant (Pogonomyrmex barbatus) colonies that collectively restrain themselves from foraging for seeds when the weather doesn’t suit them are more successful than colonies that head out regardless of conditions, according research out this month (May 15) in Nature. “It’s the first study of how natural selection is acting on collective behavior in a natural population,” study author Deborah Gordon of Stanford University told the Not Exactly Rocket Science blog, which is hosted by National Geographic.
Harvester ant colonies regulate their foraging activity with a system of positive feedback interactions. In short, if outgoing foragers bump into incoming counterparts carrying food, they are more likely to venture out themselves—and vice versa. With every individual behaving in accordance with these rules, the collective adjusts the size of its foraging crews to suit the amount of food available.
Harvester ants live in the desert, so they need the water provided by seeds, but they lose water every time they head out across the sands, so it’s a delicate trade off. Gordon found that different colonies tackle the dilemma in different ways: some are less likely to forage when conditions are dry and there is an increased risk of death by dehydration, than others. Over the course of almost 30 years, the colonies that showed restraint during dry spells survived just as long as those that collected seeds in all conditions, but produced more offspring colonies.
This collective response to changing conditions appears to be heritable: although daughter colonies were distant enough from parent colonies to ensure the two could not interact, they made similar choices regarding when to forage.
Micaria sociabilis
FILIP TRNKA, ENCYCLOPEDIA OF LIFE
Male spiders are sexual cannibals
The Black Widow spider is so called because the females of the species are known to eat their male suitors after sex—an extreme form of selection in which less desirable males are ruthlessly taken out of the game. But a new study has shown that for another species, the roles can be reversed: male Micaria sociabilis spider gobble up females after, or even before, mating. Indeed, the research—published this month in Behavioral Ecology and Sociobiology—demonstrates that M. sociabilis males are more likely to eat females than be eaten.
A team from Masaryk University in the Czech Republic studied the behavior of pairs of males and females of various sizes, ages, and mating statuses thrown together in the lab. The spiders were well fed beforehand to discount hunger as the driver of any cannibalism witnessed. The researchers found that males born in the summer, which are larger than their spring-born counterparts, were more often cannibalistic. Moreover, cannibalism occurred most frequently when young summer-born males encountered older females from the spring generation, suggesting that for males, this extreme form of selection is based on age. Variations in female body size did not affect rates of cannibalism.
Regardless of the criteria, it’s clear that male M. sociabilis spiders assert their partner preferences in the most ruthless way possible, by devouring those unfortunate members of the opposite sex not deemed fit enough.
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| ramonmercado Psycho Punk
Joined: 19 Aug 2003 Total posts: 17933 Location: Dublin Gender: Male |
| Posted: 15-09-2013 23:59 Post subject: |
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| Quote: | Behavior Brief
A round-up of recent discoveries in behavior research
http://www.the-scientist.com/?articles.view/articleNo/37467/title/Behavior-Brief/
By Tracy Vence | September 12, 2013
Location, location, location
Where koalas live within their natural habitat range affects how they behave, researchers at Australia’s University of Queensland have found. Nicole Davies and her colleagues tracked 21 koalas (Phascolarctos cinereus) living in southwest Queensland, looking for differences among animals that lived at different distances from the area’s center. Overall, Davies’s team found that koalas living at the arid Western end of the natural range spent most of their time close to water sources, while their Eastern counterparts residing nearer to the temperate center varied more in their habitat use.
“The difference in home range movement patterns and resource use among the different koala populations shows that behavior changes with proximity to the arid edge of the koala’s range,” Davies and her colleagues concluded in their paper, published today (September 12) in Movement Ecology. “Changes in home range size and resource use near the range edge highlight the importance of further range-edge studies for informing effective koala conservation and management actions, especially when developing species-specific adaptation responses to climate change.”
How and why fish school
WIKIMEDIA, U.S. FISH AND WILDLIFE SERVICE
Working to understand the complexities of social behavior, scientists at the Fred Hutchinson Cancer Research Center in Seattle have mapped characteristics associated with how and why fish swim in schools to stretches of the three-spined stickleback (Gasterosteus aculeatus) genome. In a paper appearing online today (September 12) in Current Biology, the researchers present a quantitative trait locus analysis of schooling behavior between lab-reared hybrids of strongly schooling marine sticklebacks and weakly schooling freshwater varieties. Among other things, the team found that the tendency to school and a fish’s position within a school mapped to different genomic regions. They also identified a putative genetic link between schooling position and variation in the fish’s neurosensory lateral line.
The researchers suggested that understanding how and why fish school could help them pinpoint the genetic characteristics associated with similarly complex social behaviors in other animals, and even humans. “The motivation to be social is common among fish and humans,” lead author Anna Greenwood said in a statement. “Some of the same brain regions and neurological chemicals that control human social behavior are probably involved in fish social behavior as well.”
Male orangutans plan ahead
FLICKR, MIKAKU
Planning is widely considered a uniquely human trait, but other animals have also shown an ability to plan for future needs. Writing in PLOS ONE this week (September 11), the University of Zurich’s Carel van Schaik and his colleagues showed that male Sumatran orangutans (Pongo abelii) emit long calls, which females use to position themselves within earshot.
The researchers traveled to a peat swamp forest in Sumatra’s Gunung Leuser National Park to study this calling behavior. All told, they analyzed 1,169 long calls from 15 different flanged males. They also measured the male orangutans’ travel direction at the time of each call and at half-hour intervals until they reached their night nests.
Overall, van Schaik’s team found that long calls emitted at or near the night nest tended to indicate travel direction for the next day or so. “These results show that male orangutans make their travel plans well in advance and announce them to conspecifics,” the authors wrote in their paper.
“Basically, they’re telling their female audience where they’re going,” van Schaik told Popular Science. “Instead of broadcasting, it’s narrowcasting.”
Asian elephants distinguish potential predators
FLICKR, ARRANET
In the first reported study to investigate nighttime antipredator behavior among wild Asian elephants, researchers from the University of California, Davis, showed that the animals are able to distinguish playback growls of tigers, their occasional predators, from those of leopards, which pose a much greater threat. Writing in Biology Letters this week (September 11), Vivek Thuppil and his colleagues showed that in response to tiger-growl playbacks, the elephants retreated silently. When reacting to leopard-growl playbacks, on the other hand, the animals lingered, producing aggressive vocalizations and showing alert and investigative behaviors.
“Elephants can indeed discriminate between growls of these felid species differing in dangerousness,” Thuppil and his colleagues concluded in their paper.
Lucy Bates, a research fellow at the University of St. Andrews in the U.K. who was not involved in the study, told National Geographic that “it would pay for the elephants to recognize when a tiger is nearby so they can retreat, without wasting time by running away for every big-cat growl they hear.”
Simple surroundings and social complexity
FLICKR, DISTANT HILL GARDENS
Mice raised in a stimulus-rich environment show less complexity in their social interactions than those reared in less-cluttered environments. That’s according to a study from researchers at Israel’s Weizmann Institute of Science, published earlier this month (September 2) in eLife.
To investigate high-order social interactions among mice, Elad Schneidman and his colleagues created an automatic system based on the idea of maximum entropy models from physics to track individuals within 17 small groups if mice over time. “We have found that the minimal models that rely only on individual traits and pairwise correlations between animals are not enough to capture group behavior, but that models that include third-order interactions”—the next step above pairwise dependencies for a given model—“give a very accurate description of the group,” Schneidman and his coauthors wrote in their paper.
Overall, the researchers found that mice raised in a complex and more populated environment spent significantly more time inside the large nest, compared with those reared in standard laboratory conditions, which spent more time outside of it. “Social interactions and correlated group behavior depend on past environment,” the researchers concluded. |
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| ramonmercado Psycho Punk
Joined: 19 Aug 2003 Total posts: 17933 Location: Dublin Gender: Male |
| Posted: 01-10-2013 19:28 Post subject: |
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| Quote: | A round-up of recent discoveries in behavior research
http://www.the-scientist.com/?articles.view/articleNo/37698/title/Behavior-Brief/
By Abby Olena | September 27, 2013
Pigeon pilot and copilot
Flocking behavior is a form of group decision-making that has been well modeled, but not well studied in actual birds. Work released this week (September 25) in Journal of the Royal Society Interface provides new insight into flocking behavior by showing how two homing pigeons navigate a route together.
Using high-resolution GPS, University of Oxford researchers tracked the paths of 80 pairs of homing pigeons as the birds navigated home from a familiar release site. The scientists determined that pigeon pairs usually flew side by side, ensuring that each bird could see the other at all times, thus reducing the risk of separation. As the authors explain, “if birds attend to each other mutually, leadership remains dynamic in that it can shift according to which bird has the best local information.”
By comparing the pigeons’ solo flights to the flights they took in pairs, the research team found that birds that flew faster when solo generally led their partners somewhat and dominated the choice of route. These results demonstrate “how group decisions emerge from individual differences in homing flight behavior,” the authors wrote in their paper.
Conniving cuckoo finches
FLICKR, ALAN MANSON
The African cuckoo finch (Anomalospiza imberbis) is a brood parasite. The bird shirks its parental responsibilities by laying its eggs in others’ nests. Its most common hosts, African tawny-flanked prinias (Prinia subflava), must sense which eggs are foreign and reject them in order to conserve valuable energy to care for its own offspring. In a report published in Nature Communications this week (September 24), University of Cambridge scientists described their observations of the relationship between wild cuckoo finches and prinias.
"Many brood parasites [such as cuckoo finches] and hosts are locked in ongoing evolutionary arms races, with parasites evolving attack strategies to get their eggs accepted—such as egg mimicry—and hosts evolving defenses—such as egg rejection," first author Martin Stevens told the BBC.
The researchers found that the prinias were less likely to reject cuckoo finch eggs that closely resembled their own. They also discovered that when a female cuckoo finch visited a nest multiple times, the eggs she laid were more likely to be accepted by the host. The authors suggested in their manuscript that instances of repeated parasitism are “likely to be an adaptation to increase the probability of host acceptance.”
"Our work shows that the cuckoo finch has evolved another novel strategy of attack, whereby it defeats both sensory and cognitive components of host rejection behavior," Stevens told the BBC.
Fecal fortresses
USDA, SCOTT BAUER
Researchers from the University of Florida’s Institute of Food and Agricultural Sciences in Ft. Lauderdale have shown that the fecal material subterranean termites (Coptotermes formosanus) use to build their nests encourages the growth of mutualistic bacteria, which helps protect the insects from pathogens.
Writing in the Proceedings of the Royal Society B this month (September 1, the scientists isolated more than 500 actinobacterial samples from termite nest material. When the scientists tested a representative bacterial isolate, they found that it restricted the growth of a soil fungus that can be pathogenic to termites. They also found that the presence of the same isolate increased termite survival, suggesting that defensive mutualism between bacteria and termites might contribute to the insects’ immunity.
In addition to illustrating a new mutualistic relationship between insects and bacteria, the results of the study provide insight into why biological methods of control have not been successfully used on termites. “Our new publication is a new nail in the coffin of biological control, as another layer of protection has now been identified,” first author Thomas Chouvenc told Ed Yong.
Primates whisper
FLICKR, SCHRISTIA
A family of cotton-top tamarins (Sanguinus oedipus) at Manattan’s Central Park Zoo has been caught whispering. The tamarins are the first non-human primates to be observed using whisper-like behavior, reported Rachel Morrison and Diana Reiss in Zoo Biology this month (September 13).
The researchers, based at Hunter College in New York City, intended to investigate mobbing behavior, where a group of animals swarms a perceived threat and vocalizes loudly. The scientists expected the tamarins to react strongly to one of their supervisors, toward whom they displayed mobbing behavior in the past. But the primates instead displayed fearful behaviors, approaching cautiously and then shying away from the supervisor. At the time, the researchers did not detect any vocalizations. Only upon listening to audio recordings did they observe “low amplitude vocalizations” like whistles and chirps, akin to human whispering.
“Consistent with whisper-like behavior, the amplitude of the tamarins' vocalizations was significantly reduced only in the presence of the supervisor,” the authors reported in their paper, suggesting that the primates were using the whispers to communicate with each other.
Songbirds stick together
FLICKR, LUC VIATOUR
Bolder male songbirds have a greater number of shorter-lived social associations, while shyer males generally have just a few close, relatively longer-term “friends,” according to a study published this month (September 17) in Ecology Letters.
University of Oxford’s Lucy Aplin and her colleagues, based in England, Australia, and Canada, studied a wild population of great tits (Parus major) that overwinters each year in woods near Oxford. Because this group of birds has been studied for many years, over 90 percent of them have been fitted with a tiny transponder that identifies each bird individually. The researchers assessed individual personalities by temporarily taking birds into captivity and assigning them scores based on how quickly they explored a novel environment. They also used the transponders to automatically monitor the birds’ visits to sunflower feeders throughout the woods.
By combining the personality scores with the data collected at the feeders, the researchers learned that males with similar personalities tended to stick together, and that males with higher exploration scores switched social groups more frequently than their counterparts with lower scores. These observations suggested that individual songbird personality can inform social structure.
But the implications for the team’s findings extend beyond insight into songbird sociality. “By doing this we hope to understand not only their social behavior, but how their social structure affects the spread of disease or the spread of information,” Aplin told the BBC.
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termites, primates, flock, behavior brief and avian evolution |
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