Variation of bio-acoustic signals and vocal apparatus anatomy (larynx) of <em>Eleutherodactylus coqui </em>and <em>Eleutherodactylus antillensis</em> in Puerto Rico

Abstract

The current position of the islands that make up the Caribbean Region, such as the Greater Antilles, the Lesser Antilles and the Bahamas, was a very dynamic one. Our interest in understanding the evolution of anuran communication becomes more important due to the fact these species within the Puerto Rican Bank have been isolated from each other by physical barriers for approximately 8,000- 10,000 years by the rising sea levels after the last glacial maximum, creating different niches augmenting the diversity in the Archipelago; which provides a privileged location to study evolution in a microscale for many taxa and amphibians. This study focuses in anuran communication, of two species: <em>Eleutherodactylus coqui</em> and <em>Eleutherodactylus antillensis</em>. Common species such as the ones under study gives the opportunity to explore variation across populations, these species can be found from the lowest elevations to the highest. The fact that these species cover many habitats expose them to different environmental temperatures. This variation in temperature if its beyond specific thermal thresholds may constrain physiological processes associated with sound production to such an extent that calling behavior is inhibited. To better understand these patterns, we studied two main components: acoustic communication and the anatomical features of the larynx. The results varied among species, each population's calls differ not only in acoustical parameters such as frequency and duration, but also the sound producing organ was variable within populations across the island and body size was not correlated with laryngeal morphology. Furthermore, acoustic frequencies varied with laryngeal size and shape.