Coqui Frog Predator Avoidance and Recognition
The purpose of this study was to determine whether coqui frogs from their non-native range responded to native predators the same way as frogs from their native range. Frogs were collected from two sites in Puerto Rico (El Yunque and Rio Abajo) in May 2006 and one site in Hawaii (Hilo) in June 2006. At each site, frogs were collected from a high (> 700 m) and low (< 300 m) elevation population. Of the total number of frogs collected, 100 males were randomly selected to be used in this study (45 and 55 from Hawaii and Puerto Rico, respectively). Three tailless whipscorpions (Phrynus longipes) and three tarantulas (Avicularia laeta) were also collected in Puerto Rico in field sites where frogs were collected and shipped back to a laboratory.
USDA, Animal and Plant Health Inspection Service (APHIS)
Utah State University
Half of these tests investigated avoidance of tailless whipscorpions (n = 48) and half investigated avoidance of tarantulas (n = 52). Testing occurred in 36.8 cm L × 21.8 cm W × 24.4 cm H plastic aquaria between 2000 and 2400 h, when lights were off in the rooms animals were housed in and when frogs were most active. During each test, one side of the aquaria contained a transparent, plastic cage (18.3 cm L × 10.7 cm W × 14 cm H) with a predator inside while the opposite side of the enclosure contained the same cage with no predator. These cages each had 9 cm × 11.5 cm areas cut out and filled with mesh (0.76 × 0.76-cm openings) on each of the large sides of the plastic containers, so that frogs could use olfaction as well as visual cues to observe predators.
A focal frog was introduced to the center of the aquaria in a 118 mL circular Glad® container with the lid slowly removed at the start of the experiment. Frogs had access to both sides of the aquaria. Each test included a 30-minute period during which an observer recorded the location of the frog and each time it crossed from one side of the container to the other. Additionally, we determined if the frog spent more than half of their time, once they moved, on the side of the aquarium away from or near the predator. Frog movement was recorded by the observer using a television monitor and VCR in an adjacent room. An infrared camera was used to minimize influencing frog movement. Observers were blind to the predator’s location and the frog’s collection range. Videos were subsequently watched by an independent observer to confirm timings. Between trials, predator side was randomly located, and aquaria and cages were cleaned. Individual predators were used randomly throughout the experiment. Individual frogs were never used in more than one test. Predators and frogs were not exposed to each other in the laboratory prior to the experiment.
Phrynus longipes, Avicularia laeta
Hawaii (Hilo) Puerto Rico (El Yunque and Rio Abajo)
See README file.
Natural Resources Management and Policy
This work is licensed under a Creative Commons Attribution 4.0 License.
Beard, K. H. (2020). Coqui Frog Predator Avoidance and Recognition. Utah State University. https://doi.org/10.26078/y364-k307
FilesREADME.txt (3 kB)
Coqui_Predator_Avoidance_Data.csv (7 kB)