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The Ground Spiders of Canada and Alaska

The ground spiders, or Gnaphosidae, are stealthy hunters. They live in plant litter, in crevices on tree trunks, and among stones. Most are nocturnal, spending the daylight hours hidden in silken retreats. Because of this secretive way of life, these spiders are most often collected by pitfall traps set into the ground (Martin 1978). They may also be collected by sifting through litter and by turning over stones or logs.
Until recently, ground spiders were among the least well known of North American spiders. A series of generic revisions using modern methods (Platnick 1975, Platnick and Shadab 1975a-1988, Platnic and Murphy 1984) has now improved this situation, however, and the she species and genera rest on a reasonably stable base, at least for adults of the North American fauna. Grimm (1985) has revised some European representatives. Much work remains to be done on the relationships among the numerous genera and on those of the family itself to other families of hunting spiders, as well as on behavior and ecology. Ground spiders are important to agriculture and to forestry as biological control agents. They feed largely on pests that eat various crops. They are, however, difficult to manipulate and therefore work best where they occur naturally. Crop areas should be tested and spraying practices modified to prevent the destruction of these beneficial arachnids and to make full use of their potential.