|
In March, if normal
condition , Hyla arborea begin a new cycle of life. This year, because of
the climatic factors, Hyla arborea still didn’t show up in the region we
study, at the end of April . In the swamp, where they will gather in order
to lay down the eggs, we net only Triturus
cristalinus , Triturus vulgaris, who begin their pairing dance and
the last members of Rana dalmatica . Most of the Rana dalmatica individual
had already laid down the eggs and returned to the forest.
The males of Hyla arborea are the first to appear in the swamp, after six
months of hibernation.
Each one of them occupies its territory which must contain vegetation and free
water. After they had chosen it, the male begin their concert formed by groups of sound
about 250 KHz in pack of 8 sec. And audio constituents repeated at
o,16 sec. These concerts have the role to call the female for reproduction in the just
occupied territory.
The male will never leave the territory to look for the female but it night
change the place if no female shows up after the song. When another male
com on the occupied territory, the song is different, after that if the
intruder doesn’t leave, a fight begins.
He blows up himself and croak, rushed at the intruder kicking with its muzzle
and climbing him.
The song of admitting the defeat sound like a scary croak after with he leave the territory.
The diagram of the frequencies and intensities of Hyla arborea species song is presented below. It may be
noticed the high intensity on 250 Hz.
The female appearing later are heading toward
the territory where the most power song can be heard under the conditions
we already mentioned the male catches the female with its anterior members, the female catches up a plant, half body in the water, half
outside and begins to lay down eggs. The laying of the eggs has been
observed also in the absence of water if the male catches at the female,
if there is most humidity, but in these conditions
the eggs will dry and nothing will come out.
In May, Hyla arborea leaves the swamp, go back
to the forest again.
The eggs which escape from the predators( Rana dalmatica tadpoles, insects,
etc) divide themselves and a new generation appears. The period is for
approximately 90 days, after which, the young frogs come out to land at
the edge of the swap to feed then selves with insects.
If the swap doesn’t keep its water until July, hyla arborea has no chance
to develop in that place.
There are still some questions to be answered:
-Whey in 2 place with identical conditions, do the frogs reproduce only in one of the each year ?
-Does the swap in which they were born has any importance?
-Do they keep in mind this place?
-Why do the little frogs stay on the field in their first year, and move to the
forest only in the second year?
-Which are the conditions that determine the laying of the eggs (the length of
the day, temperature, biological rhythm , humidity )?
-What happens in the "climatic strange years" , in terms of development and
behave our ?
These are only sample of questions raised during the study of amphibians behave
our ,but haw many other fascinating questions will be raised again. You
can not preserve a species if you are not familiar with its behave our and
life conditions and its interaction with other species.
We wait your constructive suggestions
and comments, opinion changes and critics at the e-mail address : hylaprjro@yahoo.com
|
