Diversity and the “Taxonomic Impediment”
Insects account for more than half of the estimated 1,586,800 species that have been formally described by scientists (Grimaldi and Engel, 2005). The most current estimates of species undescribed or unknown to science range from 10 million to 30 million (Grimaldi and Engel, 2005; Stork, 1988, 1996); and many of the most species-rich groups are among the least thoroughly characterized. Because of a lack of available expertise, it is often impossible to identify (or “determine”) specimens.
Taxonomy and its applied interface, identification, are fundamental to continuing the study and conservation of organisms. As knowledge of living systems grows more comprehensive, the scientific community demands more from taxonomy than simply identifying which species to avoid and which are edible or otherwise useful. That the rate at which species are becoming extinct appears to exceed the rate at which new species are described (Hambler and Speight, 1996) poses not merely an academic problem but a daunting challenge to understand biodiversity with economic potential before it disappears. The problem applies to the study of plant-pollinator interactions in North America as some pollinating insects, particularly beetles and flies, are yet to be discovered and described.
The Global Taxonomic Initiative is attempting to reduce the bottleneck in taxonomic research resources in the face of what has been called the greatest extinction crisis in roughly 60 million years (J.A. Thomas et al., 2004). Under
2005). The order includes within its ranks the principal managed pollinators of the world, bees in the genera Apis, Bombus, Megachile, Osmia, and Melipona, as well as numerous unmanaged species of bees (Box 2-2) and wasps that represent a variety of families.
Nearly 17,000 species of bees have been formally described, and as many as 30,000 are estimated worldwide (Michener, 2000; T. Griswold, U.S. Department of Agriculture [USDA] Bee Biology and Systematics Laboratory, presentation to the committee, October 18, 2005). Although other species are often more efficient pollinators than are honey bees on a flower-by-flower basis, honey bees are, for many reasons, the pollinator of choice for most North American crops. A. mellifera is highly suitable as a commercial pollinator because of its biology (Hoopingarner and Waller, 1992;