During animal courtship males use strikingly beautiful signals as they compete for the amorous attention of females. Examples include bright feathers of male birds and evening songs of male frogs or crickets. Why are some signals more attractive than others? Females should be attracted to signals that indicate the quality of a suitor as mate and father. But scientist John Christy from the Smithsonian and colleagues discovered a signal that is attractive for another reason.

Up to 20 layers of transparent scales on butterfly wings scatter white light to produce brilliant blue structural color. Alison Sweeney, Duke University, and collaborators at the Smithsonian Tropical Research Institute report in Nature that polarized light from iridescent female Heliconius butterflies functions as a mating signal. This may be the first example of mate recognition based on polarized light. Physical properties of wing scales may play an important role in speciation of Heliconius butterflies.

Contrary to prevailing wisdom concerning one of the most famous textbook examples of a tightly co-evolved mutualism, not every fig species is pollinated by its own unique wasp species. In this week's Proceedings of the National Academy of Sciences, Drude Molbo, postdoctoral fellow at the Smithsonian Tropical Research Institute and collaborators report that two genetically distinct species of wasps are present in at least half of the fig species surveyed.

Late last year, Frédéric Achard and colleagues published a controversial article in which they contended that earlier estimates of worldwide tropical deforestation and atmospheric carbon emissions were too high. In the February 14 issue of Science, Philip Fearnside from the National Institute for Amazonian Research in Brazil, and William Laurance from the Smithsonian Tropical Research Institute in Panama argue that the Achard study contains serious flaws rendering its conclusions about greenhouse gases unreliable.

New archaeological evidence points to an independent origin of agriculture in coastal Ecuador 10,000 to 12,000 years ago. Suddenly, the remains of larger squash plants appear in the record. The Las Vegas site, described by Dolores Piperno of the Smithsonian Tropical Research Institute (STRI) and Karen Stothert, University of Texas at Austin in the February 14th issue of Science, may predate plant domestication sites in the Mesoamerican highlands.

Tropical forest canopies, leafy landscapes scorched by uv radiation and washed by torrential rains, house some of the most diverse but least understood creatures on our planet. And canopy biologists, pioneers of a very young science, are just beginning to describe this complex interface of plant and animal life. A major contribution to this field, Arthropods of Tropical Forests, a 490-page summary of state-of-the-art tropical entomology research, has just been released by Cambridge University Press.

The Phycological Society of America (PSA), a scientific society that promotes the study of algae, will present its 2002 Prescott Prize to Diane Littler, Research Associate, and Mark Littler, Senior Scientist, of the Smithsonian National Museum of Natural History's Department of Systematic Biology, for their book Caribbean Reef Plants: An Identification Guide to the Reef Plants of the Caribbean, Bahamas, Florida and Gulf of Mexico.

Fungus-growing ants practice agriculture and have been doing so for the past 50 million years according to research published in the Jan. 17 issue of Science. These ants not only grow fungus gardens underground for food but also have adapted to handling parasitic "weeds" that infect their crops.

One of the world's largest and highest-quality set of observations on live tropical insects and their host plants has led researchers to reinterpret the structure of tropical insect communities. The team of scientists who collaborated on this analysis includes Scott Miller of the Smithsonian's National Museum of Natural History, Yves Basset of the Smithsonian Tropical Research Institute, Vojtech Novotny of the Czech Academy of Sciences and George Weiblen of the University of Minnesota.

The Smithsonian Tropical Research Institute (STRI) proudly presents A Magic Web: The Tropical Forest of Barro Colorado, published by Oxford University Press. Palms walk, transparent wings flash, teeth gnash and wasps oviposit when STRI staff ecologist, Egbert Leigh, and photographer, Christian Ziegler, team up artfully to celebrate one of the most intensively studied tropical forests on the planet, Panama's Barro Colorado Island.