| dc.description.abstract | 1. Researches were carried out in 1962—1965 in the Niepołomice Woods (latitude 50°00 N, longitude 20°20’ E) at
Staniątki (forest) and Szarów (peaty meadow).
582 sexually mature female marsh frogs (Rana arvalis arvalis Nilsson) have been examined and the weight of their
reproductive organs (including ovaries and oviducts) in the yearly cycle of life established. These measurements
were made in the following periods: first, second and third decades of April, third decade of May, second decade
of July, first decade of September, the end of September, the beginning of October, and the third decade of
October. Apart from this, the ecology, biology and population structure of the marsh frog occuring in this area
were studied. It was found that the sizes of the sexually mature female frogs range from 4.1 cm to 7.2 cm, and
that of male frogs from 4.6 cm to 7.2 cm.
The marsh frogs leave their winter quarters at the end of March or begining of April depending on the maximum air
temperature (from +8.2°C to +15.3°C ) and rainfall. Then the frogs migrate to ponds being the place of mating. At
the end of migration ovulation takes place in the female frog. Some thirteen days after leaving the winter
quarters oviposition takes place in the water showing temperatures from between +8°C to +11.3°C.
The number of eggs laid varies from 720 to 2797 depending on the size and fecundity of the female frog and the
weight of eggs.
In the vegetative period the day activity of the marsh frog is greatest between 10 o’clock in the morning and 6 in
the afternoon.
The frog’s hibernation begins in the third decade of October with the decrease in air temperatures (+1.0°C to
3.4°C). A later rise of temperature does not cause the frog to leave its place of winter sleep. The marsh frog
hibernates on land.
2. When the marsh frog leaves the place of hibernation in the first decade of of April, the weight of the
reproductive organs decreases rapidly because the eggs test weight; the weight of the ovaries being 16.19 per cent
and that of the oviducts 13.01 per cent of the total weight of body. After the ovulation in the third decade of
April, the weight of the reproductive organs decreases rapidly because the eggs move into the pseudo-uterus. The
weight of reproductive organs is smallest in the third decade of May. In this period the weight of ovaries (1.24
per cent) approximates to the weight of oviducts (1.18 per cent). From the third decade of May to the second
decade of July an increase in the weight of ovaries and oviducts takes place. In the second decade of July the
weight of ovaries (2.60 per cent) exceeds that of the oviducts (1.31 per cent). From that time a further gradual
increase in
the weight of the reproductive organs takes place until the maximum stage of development is reached in the first
decade of April. During the whole period intervening between the second decade of July and the first decade of
April the weight of ovaries exceeds that of the oviducts. | en_EN |
