http://www.sciencedaily.com/releases/2013/01/130103131110.htm
Bigger brains can make animals, well, brainier, but that boost in brain size
and ability comes at a price. That's according to new evidence reported on
January 3rd in Current Biology, a Cell Press publication, in which researchers
artificially selected guppies for large and small brain sizes.
The findings lend support to the notion that bigger brains and increased cognitive ability do go together,
a topic that has been a matter of considerable debate in recent years, said Niclas Kolm of Uppsala
University in Sweden. They also represent some of the first convincing evidence that large brains are
expensive, evolutionarily speaking.
"We provide the first experimental evidence that evolving a larger brain really is costly in terms of both gut
investment and, more importantly, reproductive output," Kolm said.
Together, the findings strongly support the idea that relative brain sizes among species are shaped
through a balance between selection for increased cognitive ability and the costs of a big brain.
After selection, large-brained guppies outscored their smaller-brained peers in a test of numerical
learning. With more energy devoted to brain-building, brainy fish -- males especially -- did have smaller
guts. They also left fewer offspring to the next generation.
Those effects were observed despite the fact that the fish were supplied with an abundance of food.
The researchers say they are curious to see what will happen in future experiments with fish in a more
competitive, semi-natural environment including limited resources and predators.
Bigger brains can make animals, well, brainier, but that boost in brain size
and ability comes at a price. That's according to new evidence reported on
January 3rd in Current Biology, a Cell Press publication, in which researchers
artificially selected guppies for large and small brain sizes.
The findings lend support to the notion that bigger brains and increased cognitive ability do go together,
a topic that has been a matter of considerable debate in recent years, said Niclas Kolm of Uppsala
University in Sweden. They also represent some of the first convincing evidence that large brains are
expensive, evolutionarily speaking.
"We provide the first experimental evidence that evolving a larger brain really is costly in terms of both gut
investment and, more importantly, reproductive output," Kolm said.
Together, the findings strongly support the idea that relative brain sizes among species are shaped
through a balance between selection for increased cognitive ability and the costs of a big brain.
After selection, large-brained guppies outscored their smaller-brained peers in a test of numerical
learning. With more energy devoted to brain-building, brainy fish -- males especially -- did have smaller
guts. They also left fewer offspring to the next generation.
Those effects were observed despite the fact that the fish were supplied with an abundance of food.
The researchers say they are curious to see what will happen in future experiments with fish in a more
competitive, semi-natural environment including limited resources and predators.
