THE EFFECT OF TEMPERATURE ON THE ACTIVITY OF CARABIDAE (COLEOPTERA) IN A FALLOW FIELD

In 1992-1994, the activity of ground surface arthropods was investigat ed on a fallow field divided into small plots with different regimes o f weed management. Daily operated pitfall traps were placed in a trans ect across the field. The aim of the study was to investigate the effe ct of temperature on the magnitude of total arthropod catches. The poo led catches of all arthropod species were poorly correlated with tempe rature since its effects were damped by differences in timing of peak abundance of the species. To compensate for the effect of this variati on groups of species with similar patterns of annual variation of abun dance were selected. The regressions of pooled catch on average daily temperature were then calculated for periods of their peak occurrence when changes of their abundance and/or behaviour were minimum. Seven a bundant carabid species were selected and regressions calculated for p eriods of April 20-May 13 (Bembidion lampros, Harpalus tardus, Poecilu s cupreus), June 25-July 25 (H. tardus, P. cupreus), and August 8-Sept ember 9 (Amara convexiuscula, H. affinis, H. distinguendus, Pseudoopho nus rufipes). By this procedure a significant effect of temperature on carabid activity was shown, similar for different species groups and periods. The catch size increased in the average by 6.3 percentage poi nts per 1 degrees C increase of average temperature. Using this temper ature/catch size relationship daily catches of several species were re calculated on a standard temperature of 20 degrees C. This procedure d ecreased the variation of daily catches by 5-31%. The decrease was pro portional to the variation of daily temperatures during the period of sampling.