(Season of reproductionin Rana catesbeiana Shaw, 1802 raised in commercial outdoor facility and influence of climatic factors on the number of spawning masses)

Abstract

The reproductive period and the effect of climatic factors upon the daily number of spawning masses were determined on 2000 couples of Rana catesbeiana raised in commercial frog farm from 1978 to 1979 and from 1981 to 1982. The reproduction takes place in spring and summer, being the number of pawning masses (Y) influenced by the temperature of the air (T), photoperiod (F), insolation (I) and solar radiation (R). In the statistical interpretation of the data, an analysis of variance with multiple regression for the linear, quadratic and cubic effects of the climatic factors on the number of daily spawning masses was carried out and the significance level was 0.05 probability. Statistical analysis included besides these studied effects the pluviometric index and the relative humidity to do the multiple regression analysis using least squares means method. The obtained equation is:

Y = - 1,040.387 + 4.0347 F í  0.005429 F² + 0.00000243 F³+0.01426 I + 4.50872 T í  0.096315 T² í  0.021627 R

The species Rana catesbeiana Shaw, 1802 shows seasonal reproduction, occurring from September through February in the studied region. Also, the spawning frequency is influenced by the photoperiod, insolation, air temperature, and solar radiation, being the temperature the most important factor of them all.