Johnstone's whistling frog
| Johnstone's whistling frog | ||||||||||||
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Eleutherodactylus johnstonei in Jamaica |
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| Eleutherodactylus johnstonei | ||||||||||||
| Barbour , 1914 |
Johnstones Whistling Frog ( Eleutherodactylus johnstonei ) is a frog from the species-rich genus of the Antilles Whistling Frogs ( Eleutherodactylus ).
distribution
Johnstones Whistling Frog is a very successful terrestrial colonist, which is distributed over the entire Caribbean and over large parts of the mainland of Central and South America. Its expansion took place mainly parallel to human influences and natural disasters, such as hurricanes or volcanoes , which change the original habitat. If such a habitat is disturbed, Johnstone's whistle frog can spread unhindered and displace other species. The other, endemic Eleutherodactylus species then tend to have lower population densities or are no longer available. However, E. johnstonei is unable to establish itself in undisturbed habitats . The origin of Johnstone's whistle frog are the Lesser Antilles in the Caribbean.
The geographical distribution of the frog is often explained by human influences, such as the plant trade. In the Botanical Garden of the University of Basel, for example, the whistling frog accidentally got into the tropical house with bromeliads or orchids and was able to establish itself there. Outside the tropics, however, the frog is not viable in the wild.
features
The small frogs (males 17–25 mm, females 17–35 mm) have a brown-green surface and large eyes with an iris that is golden at the top and brown at the bottom. The males have an inflatable sound bladder in the neck region , which enables loud calls during the mating season.
ecology
Johnstone's whistling frogs are nocturnal and can usually be found in litter , under stones or in small wooden or plant caves. However, they are very adaptive and can inhabit different habitats . They are often found in anthropogenic areas such as mown meadows, fields, gardens and next to shops and houses. The ability of this successful colonization and spreading is due to their great tolerance to high temperatures and the possibility to live decoupled from water. Studies have shown that Eleutherodactylus johnstonei are very common in pots for ornamental plants. The plant pots seem to generate ideal reproduction conditions with a good microclimate and regular irrigation. This supports the thesis that the main vector of spread is the exchange of plants.
Ants, spiders, termites and dwarf leafhoppers serve as food . Their predators are lizards, snakes and other frogs.
Reproduction
Their way of life is mostly solitary . The frogs only come together during the mating season, each male has his own territory and lures the females into his area with the typical calls. The call is species-specific and has two syllables "du-iiii", with the emphasis on the second syllable. This whistle can be repeated up to 60 times per minute, with an interval of 1–2 seconds per sound. The frogs are sexually mature after about a year, after which the frogs mate all year round, but more often during the rainy season. Reproduction takes place in leaf litter or in small caves. After a male has attracted the female, the female starts the mating process through physical contact and the male introduces different places to lay eggs. Either the female accepts a location or the male has to present additional locations. If the locations are unacceptable, the female rejects the male completely again. But if a suitable place is found, the male sits on the back of the female and the female lays an average of 14 unfertilized eggs. These are then fertilized externally by the male. This process takes between three quarters and an hour. After about 13 days, completely developed small frogs (approx. 3.5 mm long) hatch from the fertilized eggs, with the help of a small tooth to break the egg shell. Studies have shown differences in parental care. The eggs and the young frogs are only cared for by one sex (uniparental), but the caring sex can change depending on the circumstances and environmental conditions. First and foremost, the male takes care of the offspring after laying eggs. The male keeps the eggs moist with a liquid produced by the cloaca . In some cases, however, the females come back to the nest about 72 hours after laying their eggs and take care of the nest if the males fail.
Satellite behavior is observed in males who do not have the desired characteristics or are not selected for other reasons. Here the satellite males follow a male who is already calling, in the hope that the interested female will choose them instead of the whistling male.
Invasion problem
In some areas, Johnstone's whistling frog is classified as an invasive species . The transmission of disease to other species has been observed and the calls of these immigrant whistling frogs could disturb the native species and their reproductive success. In French Guiana and São Paulo , cases are known of citizens complaining about the high level of noise pollution during the night. But the problem is controversial. A study from French Guiana shows that the frog has not spread significantly even 10 years after its introduction and therefore has no potential for invasion.
Individual evidence
- ↑ Hinrich Kaiser: Origins and introductions of the Caribbean frog, Eleutherodact ylus johnstonei (Leptodactylidae): management and conservation concerns . Ed .: Biodiversity and Conservation. 6th edition. Department of Biology; La Sierra University; USA Redpath Museum; McGill University, Montreâl, Canada 1997, p. 1391-1407 .
- ↑ a b c Marcos A. Melo, Mariana L. Lyra, Ana M. Brischi, Vilma Clarice Geraldi & Célio FB Haddad: First record of the invasive frog Eleutherodactylus johnstonei (Anura: Eleutherodactylidae) in São Paulo, Brazil . Ed .: SALAMANDRA. tape 50 , no. 3 . Saõ Paulo 2014, p. 177-180 .
- ↑ a b Botanical Garden Uni Basel - whistling frogs in the tropical house. In: botgarten.unibas.ch. Retrieved April 5, 2016 .
- ↑ a b c d e f g Kimberly Pascall: Eleutherodactylus johnstonei (Johnstone's Rain Frog) . In: UWI (Ed.): The Online Guide to the Animals of Trinidad and Tobago . 2014.
- ^ A b Raffael Ernst, David Massemin, Ingo Kowarik: Non-invasive invaders from the Caribbean: the status of Johnstone's Whistling frog (Eleutherodactylus johnstonei) ten years after its introduction to Western French Guiana . Ed .: Biol Invasions. No. 13 . Springer Science + Business Media BV, 2011, p. 767-1777 .
- ^ Godfrey R. Bourne: Reproductive Behavior of Terrestrial Breeding Frogs Eleutherodactylus johnstonei in Guyana . Ed .: Journal of Herpetology. tape 31 , no. 2 . USA 1997, p. 221-229 .
- ^ A b Godfrey R. Bourne: Amphisexual parental behavior of a terrestrial breeding frog Eleutherodactylus johnstonei in Guyana . Ed .: Behavioral Ecology. tape 9 , no. 1 . USA 1997, p. 1-7 .
