Untangling the web of tropical biodiversity

Caterpillar study shows order in the complexity of tropical biodiversity

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 findings from research in Papua New Guinea will be in the Nov. 22 edition of the Proceedings of the Royal Society of London. The research paper is available on the Web at www.pubs.royalsoc.ac.uk

Due to the present high interest in tropical biodiversity, there have been numerous studies on the subject in the last 20 years. These studies reported little predictability in the structure and composition of tropical insect communities, and they were based on techniques that sample dead insects with little data on their biology. “Predictably Simple: Assemblages of Caterpillars (Lepidoptera) Feeding On Rainforest Trees in Papua New Guinea” is a study that shows a different approach. The study was conducted using 35,942 live caterpillars, each carefully handpicked from the foliage in a lowland rainforest in Papua New Guinea. These caterpillars were then reared to adults, which allowed solid identification of species.

“Our study of live insects enabled us to find and interpret insect community composition better than ever before,” said Scott Miller, chairman of the Department of Systematic Biology at the Smithsonian’s Natural History Museum. “Our methods allowed better exclusion ’tourists’–insects moving through but not actually part of the community — than in previous studies.”

This analysis of caterpillars is just one of many emerging from long-term research. Miller, Basset, Novotny and Weiblen built their study upon the work of complementary Smithsonian research programs, including those of Terry Erwin and Jonathan Coddington of the Smithsonian’s National Museum of Natural History and Steve Hubbell of the Smithsonian Tropical Research Institute. The National Science Foundation has supported the scientists’ work for the past eight years, and they have recently renewed their support for another three years.

As a result of the scientists’ study on insect herbivore assemblages in tropical forests, they have learned that there is indeed a predictable structure in caterpillar communities. This structure allows tropical insect communities to be measured and used in a variety of academic and applied studies. The scientists plan on implementing a New Guinea-wide sampling program under their new National Science Foundation grant.

The National Museum of Natural History, located at 10th Street and Constitution Avenue, N.W., welcomed more than 8.4 million people during the year 2001, making it the most visited natural history museum in the world. Opened in 1910, the museum is dedicated to maintaining and preserving the world’s most extensive collection of natural history specimens and human artifacts. It also fosters critical scientific research as well as educational programs and exhibitions that present the work of its scientists and curators to the public. The museum is part of the Smithsonian Institution, the world’s largest museum and research complex. The Smithsonian’s National Museum of Natural History is open every day from 10 a.m. to 5:30 p.m. Admission is free.