The common frog is one of the amphibians with the highest distribution in the Iberian Peninsula. It reproduces preferably in permanent areas of water where it comes into contact with the red swamp crayfish, which preys on its larvae. Research carried out by the Spaniard Germn Orizaola from the University of Uppsala (Sweden) confirms that the larvae of these frogs have developed a defensive response to the invasive species. They also have deeper tails and larger bodies if they co-exist with the crayfish.
Numerous invasive organisms are currently spreading outside of their natural habitat at an unprecedented rate, mainly due to human actions. As a result of this spread, various ecosystems have been altered and this fact seriously affects the balance of biodiversity.
More specifically, the spread of exotic predators is considered to be one of the major causes of population decline and species extinction on a global scale.
This is the case of the red swamp crayfish (Procambarus clarkii), a species native to the south of the USA and north Mexico, deliberately introduced by man in several areas on all continents, including the Iberian Peninsula.
"The first records of this invasive species were located in Extremadura and Andalusia in the seventies. From this date on, they have spread due to the number of wetland areas, to practically the whole of the Peninsula. P. clarkii is an active predator of numerous aquatic organisms, including amphibian larvae," the Spanish researcher Germn Orizaola from the University of Uppsala (Sweden) tells SINC, having published a study in the journal 'Ecology' on the interaction between the two species.
The aim of his study was to examine whether the period of co-existence with the red swamp crayfish could influence in the type of defensive response developed by the larvae of the common frog (Pelophylax perezi).
"The study involved collecting recently laid P. perezi frogspawn in fi
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