Are spiders deaf?

Spiders have all the senses we do. Spiders are not deaf, although they do not hear with ears the way people do.  Spiders "hear" by sensing vibrations in the air. They receive these vibrations through hairs and small slits all over their bodies. Humans, too, hear sounds as vibrations in the air. Our ears capture these vibrations. The spider's sense of hearing is so well fine-tuned that the spider knows the size and type of insect caught in its web, much as we would know if someone large or small were coming up the steps based on the heaviness of the person's tread. The spider also uses this sense of hearing when he courts a female by "plucking" at a pattern on the female, rather than just touching her anywhere. This is considered a proper spider introduction, letting the female know his intentions are to court her, not attack her.
http://www.smithsonianeducation.org/educators/lesson_plans/under_spell_spiders/spiderspecifics.html