Some bats may hear better by nesting in curled leaves

Nature : Curled leaves may act as sound amplifiers for certain bat species that nest inside, according to a study published today in the Proceedings of the Royal Society B. Gloriana Chaverri of the University of Costa Rica in Golfito and Erin Gillam of North Dakota State University studied Thyroptera tricolor, whose members live primarily in South America. The bats roost in groups of a half dozen or so inside the leaves of the Heliconia and Calathea plants, as the leaves first begin to unfurl. The researchers studied the acoustics of the curled leaves by playing recorded bat calls through them in a laboratory setting. What they found was that incoming calls were significantly amplified, by as much as 10 decibels, while outgoing calls were only amplified by 1–2 decibels. Both types of calls experienced distortion, however. Further study outside the lab will be needed to verify the results.