Evidence is presented for territorial behavior in a burrowing wolf spi
der, Geolycosa xera archboldi McCrone (Araneae, Lycosidae). These spid
ers live in burrows in the scrub habitats of central Florida, USA. Mea
n nearest-neighbor distances repeatedly approximate 30 cm. The constan
cy of this mean indicates that social spacing may be occurring. A test
for perceptual range showed that G. xera can respond to potential pre
y at distances greater than 30 cm, indicating that the 30-cm nearest-n
eighbor distance does not represent a distance within which larger nei
ghboring burrow-holders treat smaller neighboring conspecifics as food
. Dyadic encounters in field enclosures showed that the distance at wh
ich neighbors would not be tolerated was within the observed mean near
est-neighbor distance. In these experimental tests for territorial beh
avior, smaller dyad members lost burrows significantly more often than
larger dyad members.