Researchers have found that honey bees who consistently explore new environments for food have different genetic activity in their brains than their less-adventurous hive mates. In a demonstration how nature often uses the same tools in various settings, though sometimes to yield different mechanisms of behavior, it turns out that this genetic activity relates to making particular chemical signals, some of which are linked to behaviors such as thrill-seeking in people.
Researchers placed a hive in an enclosure with a brightly colored feeder full of sugar water and marked the bees that visited. A few days later, the researchers added a new feeder to the enclosure, while keeping the original one full of fresh sugar water. Some of the bees discovered the new feeder and were also marked. Then the researchers removed the new feeder and added a different one in a new place. Again, some of the bees discovered this new feeder. The bees that found the new feeder both times were considered scouts, while the bees that ate only at the same old feeder were considered nonscouts. The researchers then looked at what genes were active in brain tissue of scouts and nonscouts. They found differences in over 1,000 genes. [Information on the honey bee genome can be found at http://www.hgsc.bcm.tmc.edu/project-species-i-Apis%20mellifera.hgsc?pageLocation=Apis%20mellifera.]
Some of the genetic differences related to the same molecular pathways implicated in novelty-seeking in humans. In people, for example, dopamine has been linked to the reward system, reinforcing the pleasure of doing certain activities. In insects, dopamine can have an inverse role, reinforcing displeasure, or aversion to certain activities. The activity of a gene related to dopamine in the scout bees was dialed way down, which suggested that the scouts may be less averse to new experiences.
The researchers also fed some of the nonscout bees sugar water laced with some of the molecules hypothecated to encourage scout bee exploration. For example, because glutamate (among other chemicals) was higher in scouts, the researchers fed glutamate to nonscout bees. The glutamate appeared to cause the nonscouts to act more like scouts.
The work suggests that evolution may use the same genetic toolkit across species for behavioral traits, much in the way that related genes are used for building body parts, whether in a fruit fly or frog.
The work also can be interpreted as adding to the growing evidence that humans are not the only species that have "personalities," broadly defined. [See, for example, http://www.nytimes.com/2005/03/01/science/01anim.html & http://animals.howstuffworks.com/animal-facts/do-animals-have-personalities1.htm.] More about this topic in the next post. However, it is important to note that behavior in humans, and probably primates and the whale and porpoise-dolphin family on animals, is much more than genetics. As noted in prior posts there is a feedback between the environment and genes, with methylation of genes (for example) arising from environmental interactions. The whole nature-nuture debate is often ludicrously simplistic, whereas the reality of it appears to be much more subtle and complex than anyone imagined, even five years ago.
The study can be found at http://www.sciencemag.org/content/335/6073/1225.abstract.
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