Ecology of Two Burrowing Wolf Spiders (Araneae: Lycosidae) Syntopic in Florida Scrub: Burrow/Body Size Relationships and Habitat Preferences

This fourteen year long study in the Florida scrub on the Lake Wales Ridge demonstrated that visually searching for open burrows of Geolycosa spiders was an effective method for sampling populations in the winter dry season, except one year when abnormally high precipitation during an El Niño event caused many spiders to close their burrows. Not only could the two endemic Geolycosa species be identified by the architecture of their burrow entrances (G. xera archboldi McCrone was aturricolous and G. hubbelli Wallace was turricolous), but the diameter of the burrow opening was highly correlated with the size of the resident spider and the volume of its burrow. The two syntopic Geolycosa species preferred different microhabitats: G. xera archboldi regardless of size was found in barren sand (0-10% litter coverage) whereas G. hubbelli shifted preference as it grew in size (going from 20 to 80% litter coverage). In addition each species exhibited significant habitat preferences: G. xera archboldi was most common in sand pine scrub with rosemary, the most xeric and least common habitat in the scrub; G. hubbelli was most abundant in scrubby flatwoods with sand live oak and in ridge sandhill with scrub hickory, both of which are relatively mesic sites with open canopies.