Coquí

Coqui is the common name for several species of small frogs in the genus Eleutherodactylus native to Puerto Rico. They are onomatopoeically named for the very loud mating call which the males of two species, the common coqui and the mountain coqui, make at night. The coqui is one of the most common frogs in Puerto Rico with more than 16 different species found within its territory, including 13 in the El Yunque National Forest. Other species of this genus can be found in the rest of the Caribbean and elsewhere in the Neotropics, in Central and South America. The Eleutherodactylus Coqui is a national symbol to their native island, Puerto Rico. There is a Puerto Rican expression that goes “Soy de aqui como el coqui”, which translates to “I’m from here like the coqui."

The characteristics of a coqui frog

The Eleutherodactylus coqui is a small tree frog that can vary in color. These frogs can be a mixture of brown, yellow, green, and gray on the top and the bottom side of their body is either white or yellow. The eye color is a variation of brown and gold. The first word of the species' scientific classification is the genus name Eleutherodactylus which is Ancient Greek for “free toes”, referring to the fact that this species has no webbing in between its toes.^[1] The coquis have special disks instead of webbing on their feet which differentiates them from many types of frogs. The special disks on their feet help the coquis climb and stick to trees and leaves.

Habitat

Coquis live in tropical areas and have recently been discovered in different levels of elevation. This species tends to stay low to the ground and are generally found at sea level. However, the coquis are spreading and are being discovered in higher levels of elevation. Coquis can be found at up to 1200m in elevation usually in humid mountain forests or in dry forests. According to the Invasive Species Compendium the Eleutherodactylus coqui uses the nest of common native species of birds. The Puerto Rican birds are the “bananaquit (Coereba flaveola portoricensis), the Puerto Rican bullfinch (Loxigilla portoricensis) and the Puerto Rican tody (Todus mexicanus)”.^[2] Coquis tend to be in their natural habitats in the forests but it is also common for the species to appear in human habitats such as houses, parks, and near bodies of water.

Taxonomy

Coquis belong to the Eleutherodactylus genus which in Greek means free toes. Eleutherodactylus contains over 700 different species that naturally occur in the southern United States, Central America, South America, and the Caribbean. Coquis additionally have become established in Hawaii, where they are considered an invasive species.

Seventeen described species of coquis inhabit Puerto Rico. In 2007, a new species, the coqui llanero, was officially named Eleutherodactylus juanariveroi.^[3]

Kingdom: Animalia

     Phylum: Chordata

     Class: Amphibia

     Order: Anura

     Family: Leptodactylidae

     Genus: Eleutherodactylus

     Eleutherodactylus coqui Thomas 1966[4]

Role in the ecosystem

The various species of coqui control the populations of herbivorous insect species in their local environments.

The coquis' call

The coqui frog gets its name from the mating call of the male, which sounds like “coqui”. Male coqui frogs use their call to attract female frogs but also to mark their territory. When multiple male coquis are found in the same area they challenge each other by song for territory. The coqui that loses usually flees and tends to relocate to another area or compete elsewhere. Male coquis start singing around the time the sun sets and continue throughout the night, until dawn.

Reproduction

Although coquis can reproduce all year long their breeding is at its peak during the wet season which is around April until October. Female frogs tend to lay about 15 to 40 eggs about 5 times a year. Coquis differ from most other frog species because coquis lay their eggs in terrestrial plants whereas other frog species usually lay their eggs in water.^[1] Female coquis can lay about 30 eggs at a time and about 4-6 times a year. The males gather up the eggs and guard them providing protection in a nest. The eggs are supposed to be moist, so male coquis also leave the nest to collect moisture and keep the eggs hydrated when it seems they are drying out. The male frog keeps the eggs moist by touching them with his moist skin.

Life cycle stages

When it comes to the stages of a frog’s life the Eleutherodactylus coqui has a unique life cycle. Most frogs start of their life in a tadpole or larva stage with a small tail and swimming around before they start to develop legs. Instead the coquis are hatched as tiny frogs with short tails, basically skipping the tadpole stage that other frog species have to go through. All species of Eleutherodactylus are characterized by direct development in which eggs hatch into small frogs, the tadpole stage being passed in the egg itself. Due to the fact the coquis do not have a tadpole stage, bodies of water are not necessarily needed for female frogs to lay their eggs.

Once the species reaches their adult stage most do not live longer than a year but according to the National Wildlife Federation some coquis have been found to be as old as six years.^[2]

Population decline

The decline of coqui populations has accelerated since the introduction of the Batrachochytrium dendrobatidis fungus.^[5] This pathogenic fungus has been extremely devastating towards amphibian populations as the pathogen impairs the permeability of the skin. The coquis found in El Yunque are resistant to the B. dendrobatidis fungus at the expense of their size, which reduces the aptitude to survive in the wilderness (Burrowes, Longo and Rodríguez 2007). Individuals that carry this fungus resistance are more often found where the B. dendrobatidis fungus is concentrated. Although the fungus prefers humid environments, infection is more frequent in drier climates because coquis tend to cluster in humid sub-areas within this drier climate, thereby increasing the chance of spreading of the pathogen.^[5]

Control population

Overall attempts to limit or control the coqui population were unsuccessful. However, actions have been taking place in efforts to reduce the coqui population. In Hawaii, the intentional transportation of frogs is banned, and coquis are labeled as pests.

Another action that appears to be effective in decreasing the coqui population in commercial areas is having a hot shower treatment on plants. The hot shower works as a disinfestation treatment for not only the Eleutherodactylus coqui eggs, but it is also effective for the adult coquis.

When it comes to using chemicals, there are only a few that are legal. Using citric acid can be used legally in places like Hawaii but the chemical must directly contact the coquis and maybe even multiple times. However, the citric acid may impact the plants in a negative way and cause unwanted spots.^[2] Other substances that are used to control the species is hydrated lime and caffeine. Eradication techniques include hand capture and spraying with a 12% solution of citric acid along with a certification program for nurseries to prevent them from acting as centers of contagion.^[6]

Geographic distribution/invasive species

The current record from the USGS^[7] establishes that it has been identified in Puerto Rico, Hawaii, St. Croix, St. John, St. Thomas, California, and the Dominican Republic.

Coquis have become established on the Big Island of Hawai'i, where they are considered an invasive species. Coqui population density in Hawaii can reach 20,000 animals per acre and affects 50,000 acres (20,000 ha). Eradication campaigns are underway on Hawaiʻi and Maui.^[6][8][9] Some groups favor its adoption.^[10]

The Eleutherodactylus coqui was introduced to Hawaii around the late 1980s. This species found its way to the Hawaiian Islands by hiding in plants that were being transported to the islands. Studies have shown that the species has increased the nutrient cycling rates and helped those native species with the lack of nutrients to adapt in better conditions.^[11] The coquis have a small number of predators like snakes, rats, and some lizards, as a result the species population has increased over time. Another factor to the species increase in population is the fact that they can breed continuously throughout the year. However, the Eleutherodactylus coqui has negatively impacted their environment by impacting native species. The coqui frog has increased competition with native birds, and other frogs. The expansion of the Eleutherodactylus coqui has forced other creatures such as bats to seek alternatives as they start to compete for food at higher elevation. Birds and bats were not greatly impacted with the introduction of coquis to the island until they started appearing in higher ground. This species is even feeding on native spiders and insects that are close to extinction.

In popular culture

Graffito of a coqui on a woman's shoulder on the Bloomingdale trail in Humboldt Park, Chicago, a densely Puerto Rican neighborhood

Puerto Rican boy band Menudo had a song named "Coqui",^[12] which they sang on their movie Una Aventura Llamada Menudo, on a scene where coquis can be heard. you can hear the sound of a coqui in the song "Todo me recuerda a ti" by Pedro Capó.

The sound of a coqui can be heard distinctly at the beginning and end of the songs "Acércate" and "Ángel Caído",^[13] by singer Ivy Queen.

In the first movement of The Mars Volta's song "Miranda That Ghost Just Isn't Holy Anymore", 4 minutes of coqui frogs can be heard singing (credited as "The Coqui of Puerto Rico" on the album sleeve).^[14]

The sounds of coqui can be heard in various night scenes in The Rum Diary.

The coqui is sampled in the Lin-Manuel Miranda song "Almost Like Praying", and is most clearly audible at the beginning and end of the track.

See also

• Common coqui
• Fauna of Puerto Rico
• List of amphibians and reptiles of Puerto Rico
• Coqui francolin, also onomatopoeically named

References

External links

• University of Hawaii, Control of Coqui Frog in Hawaii
• State of Hawaii, Department of Agriculture, Coqui Frog Information
• Coqui Hawaiian Integration and Reeducation Project
• ITIS