Richness of plant–insect associations in Eocene Patagonia: A legacy for South American biodiversity

doi:10.1073/pnas.0500516102

Richness of plant–insect associations in Eocene Patagonia: A legacy for South American biodiversity

^*Department of Geosciences, Pennsylvania State University, University Park, PA 16802; ^‡Department of Paleobiology, Smithsonian Institution, Washington, DC 20013; ^§Department of Entomology, University of Maryland, College Park, MD 20742; ^¶Department of Earth Sciences, Denver Museum of Nature and Science, Denver, CO 80205; and ^∥Museo Paleontológico Egidio Feruglio, Trelew, 9100 Chubut, Argentina

Edited by David L. Dilcher, University of Florida, Gainesville, FL, and approved May 12, 2005 (received for review January 20, 2005)

Abstract

South America has some of the most diverse floras and insect faunas that are known, but its Cenozoic fossil record of insects and insect herbivory is sparse. We quantified insect feeding on 3,599 leaves from the speciose Laguna del Hunco flora (Chubut, Argentina), which dates to the early Eocene climatic optimum (52 million years ago) and compared the results with three well preserved, rich, and identically analyzed early- and middle-Eocene floras from the following sites in North America: Republic, WA; Green River, UT; and Sourdough, WY. We found significantly more damage diversity at Laguna del Hunco than in the North American floras, whether measured on bulk collections or on individual plant species, for both damage morphotypes and feeding groups. An ancient history of rich, specialized plant–insect associations on diverse plant lineages in warm climates may be a major factor contributing to the current biodiversity of South America.

Footnotes

↵ † To whom correspondence should be addressed. E-mail: pwilf{at}psu.edu.
Author contributions: P.W., C.C.L., K.R.J., and N.R.C. designed research; P.W., C.C.L., K.R.J., and N.R.C. performed research; P.W. and C.C.L. analyzed data; P.W. and C.C.L. wrote the paper; and P.W., C.C.L., K.R.J., and N.R.C. obtained funding for the research.
This paper was submitted directly (Track II) to the PNAS office.
Abbreviation: LH, Laguna del Hunco.
↵ ** In this article, “richness” and “diversity” have the same, traditional meaning: the number of species or other biological entities.