Category Archives: Animal Intelligence

Gangster Birds of the Kalahari Desert

A drongo in the Kalahari. (Photo/Andy Radford, University of Bristol)

Drongos, African Kalahari Desert birds with a penchant for thievery, are taking a turn towards the avian equivalent of organized crime, a new study finds.

The victims in this case, pied babblers, have long contended with the risk of drongos popping in to make off with the babblers’ hard-earned insect prey. Now it seems a set of behaviors have evolved that are taking this interaction from a purely parasitic relationship to one of more mutual benefit. Researchers found that the drongos form protection squads for foraging babblers, keeping an eye out for trouble and strong-arming danger when it arrives.

“Like any good gangster,” says Andrew Radford, a scientist with the University of Bristol who led the research team, “as well as lying and stealing, the drongos also provide protection by mobbing aerial predators and giving true alarm calls on some occasions.”

That means pied babblers can spend less time watching for predators and more time looking for prey. The relationship is not without its caveats. Drongos still aim to take advantage of babblers, crying wolf to scare the babblers and grab the insects. The babblers likely put up with it, the researchers say, because the benefit of not having to worry about predators outweighs the cost of the drongos’ antics.

The research, which is a collaboration with the Universities of Bristol, Cambridge and Cape Town, is published online in the current issue of Evolution.

Andy Radford (University of Bristol) and a pied babbler in the Kalahari. (Photo/Matthew Bell, University of Cambridge)

A pied babbler in the Kalahari. (Photo/Andy Radford, University of Bristol)

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Vegetarian spider also a smarty pants

Female Bagheera kiplingi

Adult female Bagheera kiplingi eats Beltian body harvested from ant-acacia Photo/R.L. Curry

For ages, ants have had a monopoly on the coveted acacia, protecting the plant from would-be predators in exchange for shelter and food, or so they thought. Skulking in the background, and recently discovered, is an unlikely competitor of the ant — a spider. And this is no ordinary arachnid. The Bagheera kiplingi also happens to be a vegetarian, and is the first of its kind known to science.

“This is really the first spider known to specifically ‘hunt’ plants,” said Christopher Meehan of Villanova University. “It is also the first known to go after plants as a primary food source.”

The veggie-loving tendency of this jumping spider was first discovered in Central America back in 2001 by Eric Olson of Brandeis University. Since then he has teamed up with Meehan, who independently observed the jumping spider in 2007, to learn more about this unusual creature and the extent to which it likes plants. Not only is Bagheera kiplingi the only predominant vegetarian of 40,000 known spider species with plants making up more than 90 percent of its diet, but it’s showing scientists a complex side of arachnid biology and behavior that indicates the spider’s diet is just the beginning of this animal’s surprising life history.

Bagheera defense

Adult female Bagheera kiplingi defends her nest against acacia-ant worker. Photo/R.L. Curry

Ants are aggressive defenders of the acacia plant making life difficult for outsiders who attempt to encroach on their turf. After all, they want those yummy beltian bodies all to themselves. So how is the jumping spider managing to exploit the acacia for both food and shelter?

Science is still trying to figure that out, but preliminary research shows the spiders take advantage of the invertebrate equivalent of run-down real estate, setting up residence in less-than-desirable regions of the acacia. But their ingenuity doesn’t stop there. Bagheera kiplingi are outsmarting their ant foes, said Meehan, exploiting their intelligence and agility to get around the ants. “Individuals employ diverse, situation-specific strategies to evade ants, and the ants simply cannot catch them,” he said.

As if to add insult to co-evolution, the ants may not even know when spiders are in their midst. Bagheera kiplingi literally dupes the ant by baring young that look like carbon-copies of the ants, and Meehan has reason to suspect that the spiders actually wear a sort of insect perfume that makes them smell like their would-be attackers.

More research is forthcoming, including a look at the possibility that spider dad’s help raise the babies, a virtually unheard of behavior in spider biology. In the meantime, I hear Meehan and Olson’s methods included high-definition video of these smarty-pant vegetarian spiders. Now that would be some footage to see.

Meehan and Olson’s study is available in the October 12 issue of Current Biology.


Family dining right whale style

 

For a month after birth, Southern right whale mothers and their calves rest and nurse. Then, like the pair shown here off Argentina, they start to swim faster and farther as they prepare for a long migration in the South Atlantic to reach their feeding areas. A University of Utah study found mother whales teach their calves where to eat, raising concern about whether the whales can adapt as global warming disrupts feeding grounds. (Photo/John Atkinson, Ocean Alliance)

For a month after birth, Southern right whale mothers and their calves rest and nurse. Then, like the pair shown here off Argentina, they start to swim faster and farther as they prepare for a long migration in the South Atlantic to reach their feeding areas. A University of Utah study found mother whales teach their calves where to eat, raising concern about whether the whales can adapt as global warming disrupts feeding grounds. (Photo/John Atkinson, Ocean Alliance)

Mom right whales know best when it comes to mealtime it seems. They lead calves to grub at traditional feeding grounds teaching their offspring generations of knowledge about when and where to find food. In fact whole clans of whales will dine together in the cetacean version of a family-owned dining spot. But this is one family tradition that could lead to starvation for an already vulnerable whale species if climate change causes shifts in food distribution.

Previous research by Vicky Rowntree, research associate professor of biology and a coauthor of the new study at the University of Utah, has already shown the impacts of climate change on right whale populations. When sea temperatures rise, krill disappear and right whales respond by giving birth to fewer offspring. Now these new studies into whale behavior could highlight another problem for the whales when it comes to food.

“A primary concern is, what are whales going to do with global warming, which may change the location and abundance of their prey?” asked Rowntree in a press release. “Can they adapt if they learn from their mother where to feed – or will they die?”

Rowntree and her colleagues collected skin samples from right whales and, using a novel technique in science, combined DNA and isotope analysis to determine whale lineages and where they tend to chow down. They found that related whales congregated in designated areas to feed, and that mothers teach calves in their first year of life where to find food.

Here’s to hoping that right whales will be quick to adapt if the buffet moves elsewhere.


Let bees count the ways

The honeybee might very well be the math whiz of the insect world. New research out of The Vision Centre in Australia has experimentally proven that bees can count to four, recognizing different numbers of patterns and shapes. The findings highlight a skill especially important for social insects, such as the bee, that travel long distances to find food.

Researchers trained the bees to play a game of memory while traveling through a Y-shaped maze signposted with various numbers of symbols and patterns. These patterns matched up with patterns on a second signpost which signaled a honeybee reward. Dr. Shaowu Zhang, Chief Investigator of The Vision Centre, said they controlled for elements that could otherwise influence bees’ pathfinding, such as smell or color.

In the study, bees figured out what the various signs of patterns meant based on counting.  And it’s a technique that might translate to the natural world in the form of remembering landmarks — a cluster of three trees for instance.

“There has been a lot of evidence that vertebrates, such as pigeons, dolphins or monkeys, have some numerical competence – but we never expected to find such abilities in insects,” said Dr. Zhang.

What’s the buzz for the honeybees future? Finding out if they are capable of doing simple arithmetic of course.


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