LIGHT TRAPPING AS A DEPENDENT OF MOONLIGHT AND CLOUDS

We examined in our study the theoretical catching distance and the catching results of the JMas and Jermy type light-traps in the function of the moon phases and the clouds. The clouds determine the theoretical catching distances of both the JMas and Jermy type light-traps fundamentally. The ratio of theoretical catching distances of completely overcast and clear sky is approximately 2.4:1. This difference does not appear however in the catching results. The catching of Turnip Moth (Agrotis segetum Den. et Schiff.) in moonless hours is the most successful when the sky is totally through, if it is not raining. In opposition to this, the catch decreases by the increase of the cloud cover in moonlit hours. The most moths were found in the light-trap when the sky was almost clear. The increase of cloud cover results in a reduction of the catch. The number of the Macrolepidoptera individuals and species are higher when the sky is clear than overcast in the event both the all and low clouds. It was also found that the height of cloud base also modify the light-trap catch. If the cloud base is low the light-trap catch is also low, in the opposite it is high.