MEASURING THE EFFECTIVE SAMPLING AREA OF A PHEROMONE TRAP FOR MONITORING POPULATION-DENSITY OF SOUTHERN PINE-BEETLE (COLEOPTERA, SCOLYTIDAE)

Multifunnel traps baited with frontalin and turpentine have been used to investigate dispersal of southern pine beetles, Dendroctonus fronta lis Zimmermann, and are routinely used in the southern United States t o monitor population trends of this serious forest pest. However, ther e is no quantitative data on the effective sampling area of these trap s that would allow us to convert numbers of beetles caught in a trap t o their absolute population density (numbers per hectare). We conducte d field studies to determine the effective sampling area of the multif unnel trap. Using field releases of marked beetles, we estimated how t he probability of capture declines with distance between the trap and the release point. The estimated relationship between the capture prob ability and distance is then translated into tile effective sampling a rea. The effective sampling area for the multifunnel trap was estimate d as approximate to 0.1 ha. Our results also indicate that tile captur e efficiency of a trap declines with increased density of host trees a round the trap. We discuss our findings in the context of previous stu dies that measured attraction to pheromone traps in other species of b ark beetles and in the gypsy moth.