Insect trapping space: What is it and how can we measure it experimentally?

We define dispersive space as the habitat area over which a population of non-migrating animals released from a common site dispers in a lifetime. Trapping space for randomly dispersing animals is defined as a disc whose radius equals the radius of the dispersive space plus the radius of the active space of a trap attracting and capturing the animal under consideration. We will show that trapping space can be measured experimentally by varying inter-trap distance and then plotting it against catch in the central trap of a 3 x 3 trapping array. Trapping space is twice the inter-trap distance at which catch no longer increases. The radius of trapping space for a standard codling moth, Cydia pomonella, monitoring trap was measured at 75 m, and one trap is estimated to collect moths from 1.7ha.