Teamwork: That’s what it takes to get lucky (if you’re a certain kind of firefly).
Suppose you’re a single male firefly, fluttering about on a muggy night. You flash your bioluminescent signal to try to catch a lady’s attention, but how is she going to pick out your blip from all the other points of light ablaze when various species of firefly zoom around? About 1 percent of firefly species have figured out how to beat the noise: They team up and flash their lights in an unmissable, synchronous signal. And in a study in this week’s Science, researchers unlocked the inner workings of this sexual back-and-forth.
Biologists had long known about the synchronous flashing, but had not tested the idea that each species has its own rhythm—its own signal to complete the optical call-and-response between male and female.
To do this, Andrew Moiseff of the University of Connecticut in Storrs and Jonathan Copeland at the State University of New York at Stony Brook turned to LEDs. They put female synchronous fireflies (Photinus carolinus) in a Petri dish surrounded by green LEDs, and flashed the lights in the same pattern used by male fireflies. The females responded with their signature pattern 82 per cent of the time – but only if the LEDs were synchronised. When the lights did not flash in unison, female response dropped to 10 per cent or less [New Scientist].
Apparently, in the animal kingdom, it’s better to be a girl. We have seen that women macaques are superior conversationalists. We learned that lady humpbacks enjoy long-lasting friendships. Now research published in Current Biology shows that baboon ladies with good friends around them may live longer.
At Botswana’s Moremi Game Reserve, Joan Silk of the University of California, Los Angeles and her team spied on 44 female chacma baboons over the course of six years. Among other things, Silk looked at which girls had the most visitors and how often the women picked junk out of each other’s hair. In other words, true friendship. She also tracked each baboon’s circle of friends, seeing how each lady’s top three buddies changed over time.
Silk saw a correlation between sociability and longevity. She divided the baboons into three groups, and found that the least friendly lived 7 to 18 years, while the friendliest group lived from 10 years on (they were still kicking when the study ended). They also found that those baboons who formed stable, enduring bonds were more likely to have long lives than those with flightier friendship habits.
Scientists have long thought humpbacks loners. New research shows this isn’t so: Researchers have observed some female whale form friendships that last for years. The behavior has only been observed in lady humpbacks of similar age, with the whales going their separate ways during the breeding season, but reuniting in the open ocean each summer. These bonds can be quite strong: the longest association endured for six years.
The study appears in the journal Behavioral Ecology and Sociobiology, and it also found that the whales with the longest-lasting associations gave birth to the most calves–another animal kingdom example that friendship is beneficial. The whales are probably improving their feeding efficiency, suggests lead author Christian Ramp.
“Staying together for a prolonged period of time requires a constant effort. That means that they feed together, but likely also rest together…. So an individual is adapting its behaviour to another one.” [BBC]
When it comes to the relationship between bees and African elephants, size does not matter. The massive pachyderms are terrified of bees, which can painfully sting elephants around their eyes and inside their trunks. Baby elephants are the most vulnerable to bee stings, as their skin isn’t thick enough to ward off the insects. And researchers have now found that the elephants have developed a special strategy to help them avoid these bees that scare the bejesus out of them.
When an elephant takes note of a swarm of bees, it emits a distinct rumbling call. This bee alarm, which the scientists termed a “bee rumble,” helps draw the herd’s attention to the bees and allows them to run off unharmed, the researchers write in the journal PloS ONE. What’s more, they respond to an audio recording of the bee rumble as if it were the real thing, giving farmers a tool they could potentially use to fend off unwanted elephants.
It’s not just that some birds can use tools, as primates can. Their smarts stretch even further: New research this week suggests that New Caledonian crows can solve a three-step problem, in which the three steps must be completed in succession to reach a tasty snack. Alex Taylor and colleagues document this discovery in the Proceedings of the Royal Society B.
Here’s the setup: There’s a short stick dangling from the bird’s perch on a string. That short stick isn’t long enough to grab the food that’s tucked inside a long and narrow box, but there’s a longer stick in a separate box. If the birds could figure out the first two steps—grabbing the short stick, and using it to get the longer stick—then voila, they could use the longer stick to reach the food.
When it comes to picking up clever tricks and learning to do something the way everybody else does it, social animals like humans, birds, and monkeys excel. One individual looks at what others in the group are doing and quickly learns to follow suit—an invaluable skill that scientists previously thought evolved in step with communal living.
But what about an individual that doesn’t live in a group and spends most of its life in solitude–would it still have that ability to watch and learn? Cognitive biologist Anna Wilkinson set out to answer that question by studying the red-footed tortoise, one of the loneliest beasts on the planet. These South American tortoises grow up without parents or siblings, and adults rarely cross paths. If a head-bobbing display determines that a stranger is of the opposite sex, the two will mate perfunctorily–otherwise they just ignore each other [ScienceNOW]. Yet in a new study published in Biology Letters, Wilkinson showed that even these hermits possess the ability to learn by watching others.
When vervet monkeys play follow the leader, they prefer to follow a female. That was the conclusion of Erica van de Waal, whose lengthy study of these primates in South Africa will be published this week in the Proceedings of the Royal Society B. When her team presented them with a tricky contraption they had to open to reach a tasty snack, the monkeys learned better if they watched a female from their group demonstrate the solution rather than a male.
Seeking some answers to how social learning works in monkeys, van de Waal and her colleagues headed to Loskop Dam Nature Reserve. It took four months, they say, just to acclimate the wild animals to the presence of humans. Once the monkeys were comfortable having scientists around, Van de Waal gave each group a wooden box containing a slice of apple. To get to the apple, the monkeys had to either pull open the door at one end or slide aside a door at the other. Half the box was painted black to differentiate the two ends [ScienceNOW].
Here’s a neat dolphin trick that doesn’t involve jumping through hoops. While dolphins sleep overnight (with half their brains and one eye at a time), they begin to show signs of the kind of insulin resistance that marks type 2 diabetes in humans. But when they wake up and have their breakfast, they switch back to their normal state. A research team led by Stephanie Venn-Watson announced the findings at the American Association for the Advancement of Science meeting in San Diego, and said that dolphins’ apparent ability to switch insulin resistance on and off could lead to better understanding of the disease in humans.
Insulin helps people control their levels of blood sugar, and the resistance to it inherent in type 2 diabetes means those levels can get way too high. The dolphins, though, switch on this temporary insulin resistance to their advantage, boosting blood sugar levels overnight. “Bottlenose dolphins have large brains that need sugar,” Dr Venn-Watson explained. Since their diet is very low in sugar, “it works to their advantage to have a condition that keeps blood sugar in the body… to keep the brain well fed” [BBC News].
It may not come as much of a surprise to dog-owners, but it seems that dogs and babies share similar logical abilities, as shown by a study published in Science.
Experimenters started out with a classic logic experiment, which goes like this: researchers hide a toy in location “A” multiple times while looking at a 10-month-old baby and talking to him (“Look, I have this nice ball!”). When asked to find the toy, the baby always goes to location “A.” The experimenter then hides the toy at location “B,” again while interacting with the baby. But this time, when asked to find the toy, the baby continues to search for it at location “A.” The findings hold, even when a team changes experimenters midtest. Researchers believe that infants make this error because they believe the adults have taught them something fundamental about the world (i.e., “Your toy will always be at location ‘A’”) [ScienceNow].
Pigeons alert their flockmates to impending danger not through vocalization, but by making a whistling sound with their wings as they take off in response to a threat, according to a study published in the journal Proceedings of the Royal Society B. Researchers say other birds may also have co-opted the basic mechanical sounds of flight for communication purposes.
Biologists were curious about how all the pigeons in a huge flock knew to launch themselves into the air at the same moment. Because the birds don’t use vocal calls to alert their peers, scientists hypothesized they convey the message using their wings. Researchers first recorded the sounds made by crested pigeons flying happily around a feeder, then sent in a decoy of a hawk, and recorded their flight from the faux predator. When the researchers later played the sound back for a flock of birds, they didn’t so much as twitch at the normal recording. But the rapid clap-clap-clap of the alarmed bird sent them fleeing. Similarly, when the volume or speed of the recording was manipulated, birds only reacted to emergency wing whistles [Discovery News]. Although it’s not yet known exactly how the birds make these sounds, the study’s results could do more than increase our understanding of bird communication. They could also help repel the pesky birds from places where they are annoying or even harmful, like public parks and airports.
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Image: flickr / Lip Kee