Original article appeared on the BBC website

Monkeys at the top and bottom of the social pecking order have physically different brains, research has found.

A particular network of brain areas was bigger in dominant animals, while other regions were bigger in subordinates.

The study suggests that primate brains, including ours, can be specialised for life at either end of the hierarchy.

The differences might reflect inherited tendencies toward leading or following, or the brain adapting to an animal's role in life - or a little of both.

Neuroscientists made the discovery, which appears in the journal Plos Biology, by comparing brain scans from 25 macaque monkeys that were already "on file" as part of ongoing research at the University of Oxford.


Dr MaryAnn NoonanUniversity of Oxford
"We were also looking at learning and memory and decision-making, and the changes that are going on in your brain when you're doing those things," explained Dr MaryAnn Noonan, the study's first author.

The decision to look at the animals' social status produced an unexpectedly clear result, Dr Noonan said.

"It was surprising. All our monkeys were of different ages and different genders - but with fMRI (functional magnetic resonance imaging) you can control for all of that. And we were consistently seeing these same networks coming out."

The monkeys live in groups of up to five, so the team identified their social status by watching their behaviour, then compared it to different aspects of the brain data.

In monkeys at the top of their social group, three particular bits of the brain tended to be larger (specifically the amygdala, the hypothalamus and the raphe nucleus). In subordinate monkeys, the tendency was for a different cluster of regions to be bigger (all within the striatum).

Nature plus nurtureAt either end of the social ladder, compared to monkeys in the middle, the activity in all these different brain regions was more synchronised. The researchers believe these areas together constitute brain circuits that are crucial for negotiating social situations - interpreting social and emotional cues, learning the value of certain actions, and so on.

Dr Noonan said it was particularly interesting to see different brain regions expanded at the top and the bottom of the social ladder, indicating that dominance isn't simply about being physically stronger and having an altogether bigger brain.

"It suggests that at either end [of the hierarchy], you really need a specific set of skills to be successful, and those skills are making higher neural demands on those areas of the brain," she told the BBC.

"In the animal kingdom, you might think that being dominant is all about aggression - I'm the bigger monkey, bugger off the rest of you.

"But all of this put together means that dominance might actually depend not only on aggression and physical strength, but also on forming bonds and making coalitions - and being quite smart about placing your loyalties."

The results cannot distinguish whether the differences in these monkeys' brains were there from birth, predisposing them to a particular social lot in life, or whether they reflect ongoing changes in the brain's organisation based on the demands of living with a particular status. Dr Noonan thinks that a combination of both these effects is the most likely explanation.

"It probably is both, because they're both really important mechanisms to have on board. You can imagine if you've come from 'good stock' within the monkey world, and your dad was really strong and muscly, you'll inherit those genes, and that might set your brain up in a certain way.

"But of course you're going to have to be plastic, in order to succeed and survive. You'll have to be adapting your behaviour and therefore your brain has got to adapt too."

There is no reason to suspect that the correlations identified in the study would not apply to other primates, like apes and humans.

"The regions that we've found are all there in humans and they all do similar things," Dr Noonan said.

But in our society, social position can vary considerably in different situations - so it is might be difficult to define "dominance" for a human study.

"While we might be top-dog in one circle of friends, at work we might be more of a social climber. The fluidity of our social position and how our brains adapt our behaviour to succeed in each context is the next exciting direction for this area of research."

Eavesdropping may be rude, but snooping on honeybee conversations could reveal a lot about the environment. Their unique mode of communication, the waggle dance, contains clues about the health of the landscape they live in. In effect, the bees are giving a thumbs-up or thumbs-down to different methods of conservation.

A worker honeybee performs the waggle dance to tell her hive mates where the best food is located. That suggests the dance can indicate areas of the landscape that are healthy, at least in terms of food for pollinators.

To test this, Margaret Couvillon and her colleagues from the University of Sussex in Brighton, UK, videoed and decoded 5484 waggle dances from three laboratory-maintained honeybee colonies living in 94 square kilometres of rural and urban landscapes. They divided the area into various conservation schemes, regulated by the UK government, and mapped which areas were most frequented by the bees over two years.

"Using honeybee colonies as biomonitors for environmental health is an idea that researchers have been interested in," says James Nieh from the University of California, San Diego. "However, this study uses a far larger sample size and examines the data in a more sophisticated way."

Happy foraging Most honeybees cast their votes for Castle Hill, a nature reserve rich in wildflowers, 2 kilometres from the hives. The bees also preferred to feed on farms covered by Higher Level Stewardship schemes. Such farms are supposed to set aside part of their land for wildlife and wildflowers, which may explain why the bees liked them.



However the bees did not seem particularly enticed by farms covered by Organic Entry Level Stewardship. While organic farming may seem harmonious with healthy wildlife, these schemes involve regular cutting and mowing in the first few years. "What that probably means for honeybees is that there are no flowers at all, just short grass," says Couvillon.

Listening in on honeybee conversations could be a quick and cost-effective way of evaluating costly management schemes that aim to make lands more wildlife-friendly, Couvillon says. What's more, honeybees are generalists, so identifying areas that they prefer could help other pollinators like bumblebees and butterflies.

But honeybees may not tell us everything we need to know, says Lars Chittka of Queen Mary, University of London. He says they probably prefer whichever area offers the most nectar or pollen, regardless of whether it is a diverse wildflower meadow or a vast monoculture. "So what's good for the honeybee is not necessarily good for any other species."



Extract from New Scientist website