Male nursery web spiders (Pisaura mirabilis) use the sense of smell in their legs to find mates. Researchers at the University of Greifswald used an electron microscope to discover "olfactory hairs" on the legs of adult males. Behavioral studies prove it: these hairs help the spiders to perceive the scent of potential mates. How spiders take in and process odors is crucial to a better understanding of natural ecological relationships.