The common coquí or coquí (Eleutherodactylus coqui) is a species of frog endemic to Puerto Rico belonging to the family Eleutherodactylidae. The species is named for the loud call the males make at night. This sound serves two purposes. "CO" serves to repel other males and establish territory while the "KEE" serves to attract females. Since the auditory systems of males and females respond preferentially to different notes of the male call, this is an example of a sex difference in a sensory system. The common coquí is a very important aspect of Puerto Rican culture, and it has become an unofficial territorial symbol of Puerto Rico.
The common coquí was described as a species new to science by Richard Thomas in 1966. It belongs to the genus Eleutherodactylus which in Greek means free toes. This genus contains 185 species, which are found in the Southern United States, Central America, South America, and the Caribbean.
Full-grown male coquís measure, from snout to vent, from 30 to 37 mm, with an average of 34 mm, while full-grown females measure from 36 to 52 mm, with an average of 41 mm. The location of the frog also effects the size, for example the higher the elevation, the larger the coquis become. The size differences between genders are a result of additional energy consumption related to breeding behavior by males.
Coquís are muddy-brown in mottled coloration on the top with rust-tan flanks and a light-gray belly. As tree frogs, Coquís possess sticky pads on the tips of their toes which help them adhere to moistened or slippery surfaces They do not possess webbed feet and are not adapted to swimming.
The known lifespan of the common coquí is up to 6 years in the wild, but the majority of adults do not live past one year.
The common coquis are nocturnal and their behavior is influenced by the surrounding environment, specifically the moisture levels. When humidity levels rise at night they emerge and begin climbing to their homes in the canopy. As these humidity levels decrease they move back down to lower levels where the humidity is higher. The younger coqui populations live in the understory on leaves during the drier periods. The leaves are particularly common with this population because they provide protection from invaders. As they grow into adulthood, the coquis journey up to the canopy and begin the process stated above.
Common coquís are native to the islands of Puerto Rico, Vieques and Culebra, where they are widespread and abundant; the only notable exception occurs in Puerto Rican dry forests, where the species is rarer. The common coquí is the most abundant frog in Puerto Rico, with densities estimated at 20,000 individuals/ha. Densities fluctuate depending on the season and habitat. Generally, densities are higher during the latter half of the wet season and decrease during the dry season. The species is considered a habitat generalist, occurring in a wide range of habitats, including mesic broadleaf forests, mountains, and urban areas, found in bromeliads, tree holes, and under trunks, rocks or trash. Since the species does not require bodies of water to reproduce, they can be found on most altitudes, provided sufficient moisture is available. In Puerto Rico, they are found from sea level to a maximum of 1,200 m (3,900 ft). Adults generally tend to be found at higher altitudes than juveniles.
The common coquís are often found in cohabitation with humans. Because of their unrestricted habitat use, E. coquí can commonly be found in homes and parks. E. coquí are found in natural habitats including the human mountain forest at elevations less than 1,200 meters and in the dry forest. They are found specifically within the under story of forests at all elevations up to the canopy.
Distribution as an invasive species
The species has been introduced to Colombia, Hawaii in the United States, and the Virgin Islands. It has become a densely populated invasive species in the Hawaiian Islands, where it was accidentally introduced in the late 1980s, most likely as a stowaway on potted plants, and quickly established itself on all four major islands. It is now considered a pest species by the State of Hawaii, and is on a list of 100 of the world's worst invasive alien species. As an invasive species, it can reach up to 91,000 individuals/ha, almost 5 times its maximum density in its native Puerto Rico. Higher densities in its invaded range are likely bolstered by a release from native predators, lack of interspecific competitors, and abundant food availability. In Hawaii, they have been found at a maximum of 1,170 m (3,840 ft) above sea level. They were previously introduced in the Dominican Republic and to Louisiana and Florida, but these populations have now been eradicated.
Common coquís in areas where their density exceeds 51,000/ha could consume over 300,000 invertebrates per night. Because of their large populations, Hawaii worries about both economic and ecological impacts. The common coquí currently costs this state nearly 3 million dollars a year. Its spread has been commonly through the nursery trade, and as a result many people are reluctant to buy plants from nurseries that might be infected. Those began to perform quarantines and de-infestations in order to improve their prospects. Coquis also affect real estate values in residential neighborhoods, as many refrain from buying houses where their sleep would be disturbed by the up to 73 dB call of the common coquí.
The common coquí is a generalist nocturnal predator, which can consume, as a population, 114,000 invertebrates each night per hectare. Diets vary depending on age and size, but are primarily composed of arthropods. Juveniles consume smaller prey, such as ants, while adults consume more varied diets that include spiders, moths, crickets, snails, and small frogs. The frogs are opportunistic sit-and-wait predators, and will forage on any abundant prey items. Males will occasionally consume eggs from their own clutch, likely to provide supplemental nourishment while guarding their nests.
Calling males eat less prey than quiet males, which consume most of their food by midnight, while calling males had eaten only 18% of their food by the same hour.
Common coquís reproduce over the entire year, but breeding activity peaks around the wet season. Females usually lay between 16 and 40 eggs, four to six times each year, at about eight-week intervals. Eggs are guarded from predators—other common coquís and Subulina snails—by the males. The gestation period of coquís is from 17 to 26 days. The maturation period, the time from egg to reproductive coquí, is around eight months.
Unlike most frogs, which lay their eggs in water, coquís lay their eggs on palm tree leaves or other terrestrial plants. Abandoned bird nests are also used as nests by E. coqui. The bananaquit, Puerto Rican bullfinch and Puerto Rican tody share nests with the coquí. This method of reproduction allows the coquí to live in forests, mountains and other habitats without direct dependency on water. Since eggs are laid on land, coquís bypass the tadpole stage, proceeding to develop limbs within their eggs, rather than going through a metamorphosis as a larva in water. Thus, a fully independent froglet emerges from the egg, with a small tail that is lost shortly after. This stage of direct development has allowed the coqui to become a successful terrestrial colonizer in tropical areas. Eggs hatch within eight weeks and reach reproductive maturity within one year. The common coqui releases their young from the egg using an egg tooth that the genus Eleutherodactylus forms. Both males and females fight off intruders from their nests by jumping, chasing and sometimes biting. The males are the primary caretakers of the eggs. They offer protection and moist environments through skin contact. They will leave during very dry periods in order to collect more moisture for their offspring.
|The coqui's distinct calls may be heard here, and here.|
The coqui's call (or canto in Spanish) is used both as a way of attracting a mate and to establish a territorial boundary. A coqui may enter another's territory and challenge the incumbent by starting his call, at which point they may engage in a sort of singing duel (which can last for several minutes). The first to falter in keeping up with the cadence is considered the loser and leaves the area without resorting to physical violence. This behavior is consistent across different species (which have distinctive calls), so it is possible to hear a duel where one coqui sings "COQUI" and another "COQUIRIQUI".
- Fauna of Puerto Rico
- List of amphibians and reptiles of Puerto Rico
- List of endemic fauna of Puerto Rico
- Puerto Rican spindalis
- Flor de maga
- IUCN SSC Amphibian Specialist Group (2021). "Eleutherodactylus coqui". IUCN Red List of Threatened Species. 2021: e.T56522A3041672. doi:10.2305/IUCN.UK.2021-1.RLTS.T56522A3041672.en. Retrieved 19 November 2021.
- Narins, Peter M.; Robert R. Capranica (1976). "Sexual Differences in the Auditory System of the Tree Frog Eleutherodactylus coqui". Science. 192 (4237): 378–380. Bibcode:1976Sci...192..378N. doi:10.1126/science.1257772. PMID 1257772.
- Thomas, R. (1966). "New species of antillean Eleutherodactylus". Quart. J. Florida Acad. Sci. 28: 375–391.
- Henderson and Schwartz, p. 42.
- "Eleutherodactylus coqui". Global Invasive Species Database.
- Wells, Kentwood D. (2010-02-15). The Ecology and Behavior of Amphibians. University of Chicago Press. ISBN 9780226893334.
- Douglas P. Reagan; Robert B. Waide, eds. (1996). The Food Web of a Tropical Rain Forest. University Of Chicago Press. ISBN 0-226-70600-1.
- Jarrod H. Fogarty; Francisco J. Vilella (2002). "Population dynamic of Eleutherodactylus coqui in Cordillera Forest reserves of Puerto Rico". Journal of Herpetology. 36 (2): 193–201. doi:10.1670/0022-1511(2002)036[0193:PDOECI]2.0.CO;2. JSTOR 1565991. S2CID 85874061.
- Henderson and Schwartz, p. 41.
- www.upane.it, Upane -. "GISD". www.iucngisd.org. Retrieved 2018-05-08.
- "The Rock".
- Kraus, Fred; Campbell, Earl W.; Allison, Allen; Pratt, Thane (1999). "Eleutherodactylus Frog Introductions to Hawaii" (PDF). Herpetological Review. 30 (1): 21–25. Retrieved 2018-12-22 – via Hawaiian Ecosystems at Risk.
- Campbell, Earl W. III; Kraus, Fred (2002). "Neotropical Frogs in Hawaii: Status and Management Options for an Unusual Introduced Pest" (PDF). Usda Wildlife Services - Staff Publications. Wildlife Damage Management, Internet Center for USDA national Wildlife Research Center. University of Nebraska–Lincoln. Retrieved 2007-12-13.
- Coqui frog (Eleutherodactylus coqui)
- Boudjelas, Souyad; Browne, Michael; De Poorter, Maj; Lowe, Sarah (2000). "100 of the World's Worst Invasive Alien Species: A selection from the Global Invasive Species Database" (PDF). International Union for Conservation of Nature. pp. 6, 7.
- Karen H. Beard; Robert Al-Chokhachy; Nathania C. Tuttle; Eric O'Neill (2008). "Population density estimates and growth rates of Eleutherodactylus coqui in Hawaii". Journal of Herpetology. 42 (4): 626–636. doi:10.1670/07-314R1.1. S2CID 49269778.
- "The Ecology of Eleutherodactylus coqui". issg Database. Retrieved October 15, 2006.
- Joglar, R.L.; Rios, N. (1998). "Eleutherodactylus coqui (Puerto Rican Coqui, Coquí Común) in Dominican Republic". Herpetological Review. 29: 107.
- "Coqui (Eleutherodactylus coqui) - Species Profile". nas.er.usgs.gov. Retrieved 2018-05-08.
- Woolbright, Lawrence L.; Stewart, Margaret M. (1987). "Foraging Success of the Tropical Frog, Eleutherodactylus coqui: The Cost of Calling". Copeia. 1987 (1): 69–75. doi:10.2307/1446039. JSTOR 1446039.
- Walsh, Joseph S. (September 1992). "Amphibians and Reptiles of the West Indies: Descriptions, Distributions, and Natural History.Albert Schwartz , Robert W. Henderson". The Quarterly Review of Biology. 67 (3): 380–381. doi:10.1086/417717. ISSN 0033-5770.
- Listen to this species's mating call here.
- Robert W. Henderson; A. Schwartz (1991). Amphibians and Reptiles of the West Indies: Descriptions, Distributions, and Natural History. University Press of Florida. ISBN 0-8130-1049-7.
- "Ha'ikū Residents Bring Back Quiet Nights Through Coqui Control Program". Maui Now. 2020-12-15. Retrieved 2021-01-04.