Many flying animals look for the light or sound reflected by bodies of water. Researchers in Hungary have studied dragonflies' attraction to the polarised light that bounces off water’s surface. Depending on species, these insects seem to prefer dark or light ponds to lay their eggs in, and possibly select this by looking for differences in the polarised light reflected by watery habitats. So powerful is the draw of this light that some dragonflies may even get confused. One 2007 study suggested that they can mistake the reflective surfaces of polished gravestones in cemeteries for ponds.
