Contradictory explanations for the evolution of nectar-drinking in a diverse group of bats have long puzzled scientists, but new research led by the American Museum of Natural History and Stony Brook University provides a clear answer.
The conflicting explanations come from two different types of data. Genetic data suggest that nectar feeding evolved twice in New World leaf-nosed bats whereas earlier analyses of the bats’ anatomy point to a single origin of nectar feeding. These bats are found in Central and South America and, uniquely among bats, eat nectar, fruit, frogs, lizards, and blood.
The research team was led by Andrea Cirranello, a postdoctoral research associate at the Museum, and included Nancy Simmons, a curator in the Division of Vertebrate Zoology. The researchers found that the single-origin explanation—which was based on analyses of certain anatomical features linked with feeding, such as the shape and number of teeth, a “paintbrush”-type tongue tip, and a rearrangement of the tongue muscles to accommodate longer, extensible tongues—is wrong.
By analyzing evolutionary trees from two genomic data sets alongside trees based on more than 200 anatomical traits, and by applying a battery of statistical approaches to identify where in these evolutionary trees the conflicts arose, the scientists determined that a specialized diet of nectar-feeding independently helped shape the anatomy of two lineages of New World leaf-nosed nectar bats.
“We found that anatomical traits associated with nectar feeding had evolved and been lost several times, not just in the lineages leading to the two major living groups of nectar feeders, but within groups of nectar feeders as well,” Cirranello said. “This observation further supports the hypothesis that nectar feeding evolved twice in these bats because these traits seem more labile than we had previously thought.”
The findings are published the journal Biological Reviews.
Learn more about Nancy Simmons’ research by watching the video below. See additional curator profiles on the “Meet the Scientists” channel on AMNH.tv.