Martinique Robber Frog
© 2007 Wolfgang Wuster (1 of 1)
Eleutherodactylus martinicensis , the Martinique Robber frog, is a member of the group known as whistling frogs (Kaiser 1992). Female length averages 47mm SVL and males average 32mm SVL (Kaiser and Hardy 1994) The dorsal surface is normally dark brown and there is usually a scapular chevron along with a secondary chevron and/or dorsolateral and midline stripes (Kaiser and Hardy 1994).
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Antigua and Barbuda, Dominica, Guadeloupe, Martinique, United States
U.S. state distribution from AmphibiaWeb's database: Hawaii
Eleutherodactylus martinicensis is found in the Lesser Antilles (Kaiser 1992), and has also been introduced to Hawaii (Kraus et al. 1999). It is a widely distributed generalist and over the course of a century, it has been introduced among various islands in the Lesser Antilles: St. Barthélémy (St. Barts), Guadeloupe, La Desirade, Marie-Galante, Les Saintes, Dominica, and Martinique (Kaiser 1992). Historically, E. martinicensis also occurred on Antigua, but Kaiser (1992) did not find it there during 2 years of searching and excluded this island from the range. Eleutherodactylus martinicensis has also been introduced on the island of St. Martin (IUCN 2008). On Guadaloupe the species occurs up to at least 1,250m asl (IUCN 2008). Kaiser (1992) found that colonial trade boundaries match the range of E. martinicensis in the Lesser Antilles, and that trade has probably affected the species distribution.
Eleutherodactylus martinicensis prefer lush tropical habitats near water, but will utilize other habitats (Kaiser 1992). On St. Barts, an island with a considerably drier climate and no tropical forest, these frogs are found in moist, insect-rich areas near human habitation such as irrigation canals and compost piles (Kaiser 1992). When introduced, they are typically present in lowland agricultural areas, but are absent from higher elevation native forests (Kaiser 1992).
Life History, Abundance, Activity, and Special Behaviors
Eleutherodactylus martinicensis is nocturnal and is active throughout the year (Kaiser 1992). Males perch in vegetation about a meter off the ground to call and are typically found on agave, broad-leafed grasses, etc. (Kaiser 1992). The call is .35 seconds long and is composed of two notes (Kaiser 1992). The first note (2000 Hz) is a short call directed against competitors and the second, longer note (starting at 3200 Hz and culminating at 4200 Hz) is to attract potential mates (Kaiser 1992).
This species breeds in sites with abundant ground cover and high moisture in the soil, such as decaying plant foliage or compost heaps (Kaiser 1992). The terrestrial eggs (Kaiser 1992) are relatively large (up to 4.0 mm in diameter) and covered with a thick layer of jelly (Lynn 1961). The jelly protects the eggs from desiccation. Eleutherodactylus have direct development and hatch from eggs as froglets (Lynn 1961). About eight hours after hatching, the froglets are about 5 mm in length. Juvenile froglets are sustained on yolk for a few days, but will also accept small insects like fruit flies (Lynn 1961). Adults are insectivorous (Kaiser 1992).
These frogs remain hidden under rocks and logs during the daylight hours to avoid predation (Kaiser 1992). Additionally, aquatic predators are avoided since E. martinicensis are direct developers (Lynn 1961). Nesting Guadaloupe woodpeckers have been known to prey on E. martinicensis (Villard and Pavis 1998) and gather them to feed to their nestlings. Of a total of 248 prey items collected from woodpecker nestlings, 11% were E. martinicensis (Villard and Pavis 1998). Rats, cats, and mongeese will also feed on E. martinicensis (IUCN 2008).
Trichospirura amphibiophila, a nematode found in the abdominal cavity of E. martinicensis, was the first of its genus to be found in amphibians (Moravec and Kaiser 1994). Goldberg et al. (1998) found that E. martinicensis were also infected with three helminth species: plerocercoid cysts, Porrocaecum sp. larvae and oligacanthorhynchid cystacanths.
On Guadaloupe, where E. martinicensis has been introduced, it is parapatric with native species of Eleutherodactylus that are found in higher elevations (Kaiser 1992). Additionally, E. johnstonei seems to be displacing E. martinicensis on various islands (Kaiser and Hardy 1994). Kaiser (1992) also pointed out that deforestation and agriculture have most likely forced endemic, more specialized frogs out of areas where the generalist E. martinicensis was able to flourish.
Trends and Threats
Of all the whistling frogs, E. martinicensis was once described as one of the most common and widely distributed (Kaiser 1992). However, IUCN (2008) now classifies E. martinicensis as near threatened, and as having been extirpated from the island of St. Lucia. Introduced predators such as rats, cats and mongeese, as well as deforestation and pesticides have all been instrumental in the decline of E. martinicensis as well as other native herpetofauna. The sympatric species Eleutherodactylus johnstonei may be outcompeting E. martinicensis in more open areas (IUCN 2008). E. martinicensis does occur in several protected areas (IUCN 2008).
Relation to Humans
Possible reasons for amphibian decline
General habitat alteration and loss
Kaiser (1997) surmised that many museum specimens labeled as E. martinicensis are actually E. johnstonei, and reports on the taxonomic confusion surrounding the two names in the literature.
Goldberg, S.R., Bursey, C.R., and Kaiser, H. (1998). ''Gastrointestinal helminths of five species of Eleutherodactylus (Anura: Leptodactylidae) from the West Indies.'' Caribbean Journal of Science, 34, 146-149.
Hughes, A. (1962). ''An experimental study on relationships between limb and spinal cord in the embryo of Eleutherodactylus martinicensis.'' Journal of Embryology and Experimental Morphology, 10, 575-601.
Hughes, A. (1964). ''Further experiments on the innervation and function of grafted supernumerary limbs in the embryo of Eleutherodactylus martinicensis.'' Journal of Embryology and Experimental Morphology, 12, 229-245.
Hughes, A. (1964). ''Innervation of supernumerary and replacing grafts of limbs in Eleutherodactylus martinicensis.'' Journal of Embryology and Experimental Morphology, 12, 27-41.
Hughes, A. (1964). ''Innervation of xenografted limbs in the embryo of Eleutherodactylus martinicensis.'' Journal of Anatomy, 98, 385-396.
Hughes, A. (1965). ''A quantitative study of the development of nerves in the hind-limb of Eleutherodactylus martinicensis.'' Journal of Embryology and Experimental Morphology, 13, 9-34.
Hughes, A. (1966). ''Spontaneous movements in the embryo of Eleutherodactylus martinicensis.'' Nature, 211, 51-53.
Hughes, A. (1966). ''The thyroid and the development of the nervous system in Eleutherodactylus martinicensis - an experimental study.'' Journal of Embryology and Experimental Morphology, 16, 401-430.
Hughes, A., and Egar, M. (1972). ''Innervation of the hind limb of Eleutherodactylus martinicensis - further comparison of cell and fiber numbers during development.'' Journal of Embryology and Experimental Morphology, 27, 389-412.
IUCN (2008). 2008 IUCN Red List of Threatened Species. www.iucnredlist.org. Downloaded on 09 December 2008.
Kaiser, H. (1992). ''The trade-mediated introduction of Eleutherodactylus martinicensis (Anura, Leptodactylidae) on St-Barthélémy, French-Antilles, and its implications for Lesser Antillean biogeography.'' Journal of Herpetology, 26, 264-273.
Kaiser, H. (1997). ''Origins and introductions of the Caribbean frog, Eleutherodactylus johnstonei (Leptodactylidae): management and conservation concerns.'' Biodiversity and Conservation, 6, 1391-1407.
Kaiser, H., and Hardy, J.D., Jr. (1994). ''Eleutherodactylus martinicensis.'' Catalogue of American Amphibians and Reptiles, 582, 1-4.
Kraus, F., Campbell, E.W., Allison, A. and Pratt, T. (1999). ''Eleutherodactylus frog introductions to Hawaii.'' Herpetological Review, 30, 21-25.
Lynn, W.G. (1961). ''Types of amphibian metamorphosis.'' American Zoologist, 1, 151-161.
Lynn, W.G., and Peadon, A.M. (1955). ''The role of the thyroid gland in direct development in the anuran, Eleutherodactylus martinicensis.'' Growth, 19, 263-286.
Moravec, F., and Kaiser, H. (1994). ''Trichospirura amphibiophila n. sp. (Nematoda, Rhabdochonidae ) in the frog Eleutherodactylus martinicensis from La Desirade, French Antilles.'' Journal of Parasitology, 80, 121-125.
Villard, P., and Pavis, C. (1998). ''Diet of nestling Guadeloupe Woodpeckers.'' Journal of Field Ornithology , 69, 415-418.
Written by Jodi L. Massie (salamander1 AT knology.net), Black Hills State University
First submitted 2008-11-18
Edited by Kellie Whittaker (2009-02-21)
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