Swarming locusts need larger brains
http://www.admin.cam.ac.uk/news/dp/2010052401 (http://www.admin.cam.ac.uk/news/dp/2010052401)
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Despite being smaller than solitary locusts, swarming locusts developed brains that were 30% larger. Not only that, regions of the brain that are dedicated to different tasks had very different proportions in the two phases.
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