COEVOLUTIONARY PATTERNS IN CENTRAL AMERICAN BIGNONIACEAE' ALWYN H. GENTRY-The 600 species of the family Bignoniaceae are mostly large-flowered, wind-dispersed, woody, tropical plants. Division of the family into three major tribes -Tecomeae, Bignonieae, and Crescentieae-is based primarily on fruit mor-phology. In the neotropics the majority of the species are lianas, virtually all belonging to the Bignonieae. The neotropical Tecomeae and Crescentieae (ex-cluding Schlegelia) are arborescent. Bignoniaceae is one of the most important families of woody plants and the most important family of lianas in the Central American forest ecosystems I have studied. This is true no matter whether diversity, frequency of occurrence, or density is chosen as an index of importance (Gentry, 1972, and in preparation). The coevolutionary patterns found in such an important family are clearly very important to understanding the evolution of the adaptive strategies of the animais which interact with these plants. Several aspects of bignon biology indicate long histories of coevolution with various groups of animais. I will note sepa-rately some evolutionary diversifications in the family related to interactions with herbivores, frugivores, and pollinators. VEGETATIVE INTERACTIONS Non-reproductive interactions of bignons with animais have led to the de-velopment of different kinds of defensive mechanisms against herbivores. Chem-ical defenses in the Bignoniaceae appear to be very effective. In the field the level of herbivore damage to bignons is generally low, and even when dried plants of this family are remarkably resistant to insects (Lewis, 1971). The wood of this family is much prized for construction because of its great durability. Beams of Tabebuia wood, known to have been exposed to the elements for 400 years, are still free of decay (Record & Hess, 1940). Tahebuia guayacan is one of the most durable woods of Panama with respect to terrestrial organisms, and the few sound trees remaining from the forest inundated over 50 years ago by Gatun Lake are mostly T. guayacan (Southwell & Bultman, 1971). Resistance to her-bivores and wood-destroying insects is related to the presence of large quantities of lapachol in many species of the family ( Sandermann & Dietrichs, 1957; Gentry, 1967). Other genera are presumably protected by such unidentified chemical SThis paper is based on a section of a Ph.D. dissertation submitted to the graduate schoolof Washington University of St. Louis. I would like to thank John Dwyer, Walter Lewis,Alan Covich, Owen Sexton, Thomas Croat, Robert Colwell, Dan Janzen, Herbert Baker, andothers for useful comments on earlier versions of the manuscript; Peter Raven's criticisms ofthe final version were especially helpfil. Robert )ressler assisted greatly with identificationof pollinators. Support for this study was provided by a National Science Foundation grad-nate fellowship, an NSF predoctoral dissertation improvement grant (GB-28496), and NSFgrant GB-40103. " Missouri Botanical Garden, 2315 Tower Grove Avenue, St. Louis, Missouri 63110.ANN. MissoumI BOT. GAU>). 61: 728-759. 1974.
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