It has been demonstrated that ectotherms (such as insects and reptiles) in warm climates tolerate higher temperatures than ectotherms in cooler climates. angilletta hypothesized that urban heat islands could lead to similar differences in heat tolerance between urban and rural populations of leaf-cutter ants. he predicted that ants in urban areas would tolerate heat better than ants in nearby rural areas. select the two best experimental designs for comparing the thermal tolerance of ants in urban areas to ants in nearby rural areas.