Many current standard guidelines for delimitation surveys call for square trapping grids, but a circle design is more efficient. As this diagram shows, a pest that can reach the far corner of a square grid can easily reach beyond the grid if moving in a different direction. Conversely, a square grid large enough to cover a pest’s maximum travel radius would cover excess area—21.5 percent more than needed. (Image originally published in Caton et al 2021, Journal of Economic Entomology)