Light trapping of heart and dart moth (Scotia exclamationis L.) at passing weather fronts

A unique light trap (Jermy-type) system has been working since 4 decades in Hungary that extends over the whole country. The efficiency of collecting is, however, influenced by a number of abiotic environmental factors. From among these the effects of weather-fronts and microbarographic oscillations were studied to facilitate the processing of the immense catch data for forecasting purposes. The meteorological data were furnished by the hourly readings of the Hungarian Meteorological Institute. The fronts and boundary surfaces between fronts were characterized after Berkes (1961). From the light trap catch material of 6 stations working in the surroundings of Budapest the data of the heart and dart moth (Scotia exclamationis L.) were chosen. By processing the data of weather fronts and boundary surfaces between them those cases were studied separately when only individual fronts prevailed countrary to situations when two different fronts followed each other. The trapping success was compared to the microbarographic oscillations and their changes during the same night. From the catch data relative values were calculated and coordinated to the relevant meteorological data. The significance levels compared to the average of other data was calculated by using a t-test. The light trapping success is usually increased by weak warm fronts, strong unstable and paradox cold fronts, warm and orographic occlusions and by disintegrating processes between two boundary surfaced. The cold fronts, masked cold fronts, weak paradox cold fronts, cold occlusions, weak and cold stationary air masses, weak fronts that arrive as cold and leave as warm air, strong subsidences and downdrafts, these all are disadvantageous for successful trapping. In some cases the arriving strong and weak fronts modified inversely the numbers of trapped moths. On those nights when various weather fronts followed each other both successful and unsuccessful trappings were experienced. From the fact that both (warm and cold) fronts may result in either high or low catches it can be concluded that even among insects there may be individuals that are especially sensitive to cold or warm fronts, respectively. There also a marked modifying effect of microbarographic oscillations was noticed