Population estimates for the Amazon basin just before Europeans arrived range from 2 to 10 million people. A new reconstruction of Amazonian prehistory by Smithsonian scientist Dolores R. Piperno and colleagues suggests that large areas of western Amazonia were sparsely inhabited. This clashes with the belief that most of Amazonia, including forests far removed from major rivers, was heavily occupied and modified. See this publication in the June 15 issue of Science.

Pooling funds and putting their heads together, more than 70 scientists from 9 institutions including the Smithsonian Tropical Research Institute, sequenced the entire genome of the butterfly genus Heliconius, a brightly colored favorite of collectors and scientists since the Victorian era. Their results are published in the prestigious journal, Nature.

From Mar. 4-10, Eldredge Bermingham, Director of the Smithsonian Tropical Research Institute and staff scientist Hector Guzman joined Mission Blue, founded by Sylvia Earle, oceanographer and environmental advocate, to survey the fauna of Panama's Hannibal Bank and environs.

Researchers at the Smithsonian Tropical Research Institute and University of Costa Rica asked why spiders do not stick to their own sticky webs. Repeating old, widely quoted but poorly documented studies with modern equipment and techniques, they discovered that spiders' legs are protected by a covering of branching hairs and by a non-stick chemical coating and that they modify their behavior to avoid getting stuck.

The Smithsonian Tropical Research Institute has released the first completely portable bilingual species identification guide for the shore fishes of the tropical Eastern Pacific as a free iPhone application. Unique fish-finding, list-making tools and range maps make the app a powerful tool for scientists, divers and tour guides and a model for future phone-based field guides.

People living along the coast of Peru were eating popcorn 1,000 years earlier than previously reported and before ceramic pottery was used there, according to a new paper in the Proceedings of the National Academy of Sciences co-authored by Dolores Piperno, curator of New World archaeology at the Smithsonian's National Museum of Natural History and emeritus staff scientist at the Smithsonian Tropical Research Institute.

Small monkey groups may win territorial disputes against larger groups because some members of larger, invading groups avoid aggressive encounters. In a new report published in Proceedings of the National Academy of Sciences, Margaret Crofoot and Ian Gilby of the Smithsonian Tropical Research Institute and the Max Planck Institute of Ornithology show that individual monkeys that don't participate in conflicts prevent large groups from achieving their competitive potential.