Using a method based on geographic positioning systems that allowed them to characterize the topography of the bats' molars in a way similar to how geographers characterize mountain surfaces, the researchers calculated a measure of dental complexity that reflects how "rugged" the surface of the tooth is. They illustrate a trend from relative simplicity of the shearing molars in insect eaters and omnivores to high complexity of the crushing molars in fruit eaters.
Working with field-collected bat skulls, researchers Sharlene Santana and Betsy Dumont of UMass Amherst, with Suzanne Strait of Marshall University, W. Va., compared the structure of molars across 17 species of the New World leaf-nosed bats that specialize in a variety of different diets (insects, fruits, and a combination). It's well known that mammalian tooth structure and function are strongly related to diet, but this study goes further, the authors explain, to directly measure trends in the relationships among diet, tooth structure, feeding performance and feeding behavior.
They found that the molars of fruit-eating species had sharp outer edges that likely allow them to pierce tough fruit skin and pulp, plus large surfaces with tiny indentations that may help them grind fruit pulp efficiently. By contrast, the molars of insect-eating species were less complex, possibly because of their smoother shearing surfaces. The more simply-shaped teeth would presumably be good for cutting through hard insect exoskeleton. This study is published in the Feb. 16 online issue of the journal Functional Ecology.
Santana and colleagues further tested if, within insect-eating species, higher molar complexity was related to a greater ability to crush insect prey. They fed beetles to field-caught bats, recorded their feeding behavior, then collected fecal samples to measure how well the beetles had been broken down. "We found that insect-eating bats with more complex molars were bett
|Contact: Janet Lathrop|