Acoustic monitoring, calling behavior traits, and jumping performance of the Melodious Coqui frog (<em>Eleutherodactylus wightmanae</em>) across its longitudinal range.

Abstract

An assessment of the Melodious Coqui frog (<em>Eleutherodactylus wightmanae</em>) was conducted in three mountain forests (the Cayey, Toro Negro, and Maricao forests) across the east-west humidity gradient in Puerto Rico. In the three sites, I evaluated the calling activity, calling traits, and the jumping performance of the ecological specialist <em>E. wightmanae</em> compared to the generalist <em>Eleutherodactylus coqui</em>. Significant differences in calling activity were observed across study sites, with more individuals actively calling in the Toro Negro forest during the Warm-wet season. In contrast, in the Maricao forest, calling activity was significantly higher during the cold-dry season, while very little seasonality was observed in the Cayey forest. Seasonal changes in body size were also detected, with males being significantly larger in the cold-dry season across all sites, while those from the Maricao forest were the smallest during this season. Body size moderately affected calling behavior traits like the duration and rate of the type-2 note, adding a slight variation to the note&rsquo;s peak frequency and intensity. Calling males from the Toro Negro forest had the lowest peak frequencies, longer duration, and highest intensity of type-2 note repetition rate. In contrast, callers from Cayey had the highest type-2 note repetition rate.<br /> <br /> Seasonal differences in note intensity were evident in Maricao and Cayey populations, with those from Maricao having the highest intensity of type-2 note of all sites during the cold-dry season. Lastly, jumping performance significantly differed between species. Males of E. wightmanae jumped farther than those of <em>E. coqui</em>. In addition, individuals of both species jumped significantly farther at 24ºC, with individuals from the Toro Negro forest jumping the longest distance. No significant effect between temperature treatments was found in speed per jump. However, spatial differences were observed within species, with males of <em>E. coqui</em> from Cayey being the slowest, while those of <em>E. wightmanae</em> from Maricao being the slowest. Further research should incorporate genetic analyses to examine variation in these traits. Also, long-term population monitoring at Toro Negro and Maricao forests is needed to detect population fluctuations indicative of potential extirpations with the projected climatic changes in Puerto Rico.