Beltane marks the "birth of summer" and -- the birth of all spirits.. (and six months from now, the death of summer, a day that marks when the souls of all the dead depart the earth--the evening before they depart, the are restless, and looking for a place to hide and stay.. it is a night when all the spirits walk the earth. (ie, halloween!)

many of the mayday celebrations are fertility related.. fertile soil, and fruit trees (my apple trees are in blossum now) and other fruits. and late night celebrations in the cool night air, watching a bon fire might have lead to snuggling close, and a different sort of lei day!