Improved Methods for Survey of Carabid Beetles (Coleoptera: Carabidae) Using Pitfall Trapping and Spatial Autocorrelation Techniques

Abstract

Ground beetles (Coleoptera: Carabidae) inhabiting a peach orchard were collected using pitfall traps placed adjacent to plastic barriers that were perpendicular to each other and crossed each other at their midpoints. Each array of traps contained 5 traps with 1 at the midpoint of each barrier and the other 4 at the ends of each plastic barrier. The trap located at the center of each array captured about 40% of the total beetles trapped by each array, thus suggesting that a single trap located at the center of the array could be a more efficient means of sampling. Using spatial autocorrelation techniques, the range of spatial dependence for the two herbivorous carabids collected in this study - Harpalus tschiliensis Schauberger and Harpalus griseus Panzer - ranged from 136.7 - 210.3 m, whereas that of the predatory carabid Calathus halensi Schailer ranged from 330.1 - 412.4 m. Based upon our results, we suggest that pitfall traps used for monitoring or sampling carabid beetles be set no further than 210 m apart for herbivorous species and 412 m apart for carnivorous species.