Concerning the question of why the relative brain sizes of smaller organisms are larger:
Doesn't it seem obvious that this is due to the entirely different nature of the nervous system and its function compared to other tissues? For example, a salivary gland will work the same whether it has 10,000 or 20,000 cells, appropriate to two species of fruit flies, one twice the size of the other. But given that neurons have a lower limit in size (as the article points out), one cannot halve the number of neurons and achieve the same behavioral complexity. And a fly half the size needs roughly the same behavioral reportoire, since it must react to threats, find food and mates, etc. pretty much the same.
posted by Bruce Blackwell
May 21, 2012
JSTOR, the online academic archive, contains complete back issues of American Scientist from 1913 (known then as the Sigma Xi Quarterly) through 2005.
The table of contents for each issue is freely available to all users; those with institutional access can read each complete issue.
View the full collection here.
An early peek at each new issue, with descriptions of feature articles, columns, and more. Issues contain links to everything in the latest issue's table of contents.News of book reviews published in American Scientist and around the web, as well as other noteworthy happenings in the world of science books.
To sign up for automatic emails of the American Scientist Update and Scientists' Nightstand issues, create an online profile, then sign up in the My AmSci area.