Shahparonov V.V., Ogurtsov S.V., 2003. Ecological mechanisms of dispersal of the green toad (Bufo viridis Laur.) youngs-of-the-year // Mobility of students and programmes flexibility in the prospect of the European unification of the training processes in ecology and environmental science. Italian-Russian student forum. Thesis of the forum. Palermo, 23-26 July, 2003, p.64.
Ecology of young amphibia (soon after metamorphosis) have been studied less than the ecology of adults. In particular we do not know exactly the dynamics of disperse in yearlings of some anuran species.
Our field observations ( at the north-west of Moscow region) show that green toad B. viridis remains near the native pond at least several days after metamorphosis. Toadlets with rudiment of tail keep within 1m from the edge of the native pond and jump to the pond if they feel danger. Soon after metamorphosis tailless toadlets could occupy the area up to 5m from the native pond. Being disturbed they prefer to escape to surrounding vegetation. In conditions of pair-choice test toadlets of the first group prefer water from the native pond to water from the strange one. Tailless toadlets caught within 1m from the water body as well as toadlets caught between 1 to 5 m from the pond demonstrate indifference to native pond water. Tailless youngs of the year caught in area beyond 5 m from edge of pond reject the odour of the native pond compared with unfamiliar water.
Tadpoles exposed to artificial chemical marker - morpholine, 10-7 mole/l – on Gosner larval stages 19-21, i.e. during 4 days between hatching and the beginning of active feeding, show preference to morpholine (10-8 mole/l) after metamorphosis. Toadlets fail to form preference to morpholine when exposed to it during the same time period after metamorphosis. They remain indifferent as do the control toadlets that are not acquainted with morpholine.
These results show that B.viridis dispersal use native pound odour for orientation. Chemical stimuli could be learnt during a sensitive period in larval development.