Among the processes by which researchers gauge the effectiveness of a mosquito repellent is one that depends on convincing a volunteer to shove an arm treated with the compound into a box and let the little bloodsuckers have a go at it. The system works well enough but, like all such assays, has limitations, not the least of which is finding volunteers. Due to odors and other variable skin characteristics,
moreover, not all humans provoke the same response by mosquitoes, creating troublesome variable.
Another method uses a heat source to mimic a warm body and collagen membrane as a substitute for human skin, placed over a container holding human blood, within what amounts to a small plastic box. It is effective, but the small size of the module inhibits mosquito flight, an indicator of repellence, as well as the number of mosquitoes used during a test.