In dangerous environments, females looking for a mate run great risks. Scientists from Seoul National University, in Korea, and the Smithsonian Tropical Research Institute in Panama present a new take on sexual signaling in the May issue of the Public Library of Science. The researchers report that females prefer a male sexual signal that helps them avoid their predators as they sequentially visit and assess potential mates.

Drought tolerance is a critical determinant of tropical plant distributions, researchers working at the Smithsonian Tropical Research Institute in Panama report in the journal Nature, May 3. In a novel coupling of experimental measurements and observed plant distributions across a tropical landscape, drought tolerance predicted plant distributions at both local and regional scales. This mechanism to explain a common observation will contribute significantly to models of land use and climate change.

Lizards gave rise to legless snakes. Cave fishes don't have eyeballs. In evolution, complicated structures often get lost. Dollo's Law states that complicated structures can't be re-evolved because the genes that code for them were lost or have mutated. A group of sea snails breaks Dollo's law, Rachel Collin, staff scientist at the Smithsonian Tropical Research Institute and colleagues from two Chilean universities announce in the April, 2007, Biological Bulletin.

Smithsonian scientists and colleagues report a new study that may shake up the way paleontologists think about how environmental change shapes life on Earth. The researchers summarized the environmental, ecological and evolutionary consequences for Caribbean shallow-water marine communities when the Isthmus of Panama was formed. They concluded that extinctions resulting when one ocean became two were delayed by 2 million years.

Smithsonian scientists have discovered a biodiversity bounty in the Eastern Pacific -- approximately 50 percent of the organisms found in some groups are new to science. The research team spent 11 days in the Eastern Pacific, a unique, understudied region off the coast of Panama.

A new form of stem rust, a virulent wheat disease, has jumped from eastern Africa and is now infecting wheat in Yemen in the Arabian Peninsula.