1984] 
Miller — Geolycosa 
129 
Riechert and Luczack (1982) recently reviewed the literature 
concerning the selection of microhabitat in spiders. Environmental 
factors such as wind (e.g., Eberhard, 1971), vegetation structure 
(e.g., Enders, 1975) or temperature (e.g., Riechert and Tracy, 1975) 
and prey characteristics such as prey availability (e.g., Kronk and 
Riechert, 1979; Enders, 1977; Morse, 1981) are known to influence 
positioning of webs and the location of foraging sites in spiders. 
Geolycosa burrows function in both thermoregulation (Humphreys, 
1975) and prey capture (Gertsch, 1942, pers. observ.), so the 
placement of the burrow may be related to these functions. 
However, the major thermoregulatory attribute of the burrow is its 
depth and not its location relative to the surrounding vegetation 
(Humphreys, 1975). Geolycosa regulate body temperature by 
moving up or down the tunnel. The selection of a burrow site, 
therefore, is more likely to be related to prey availability and 
microhabitat factors relating to ease of construction or which 
provide some protection from predators. 
The results show a difference between G. turricola and G. 
micanopy in the relationship between vegetation availability and 
frequency of burrow establishment. Within a feeding state, the 
number of burrows established is independent of vegetation for G. 
micanopy but not for G. turricola. This difference reflects the turret 
construction habits of the two species. Geolycosa turricola nearly 
always constructs a conspicuous turret from whatever material is 
available, whereas G. micanopy shows considerable variation in 
turret construction and often has burrows with no turret (Wallace, 
1942). The different relationship between burrowing frequency and 
vegetation is probably not a result of a preference for vegetation 
material used in the experiments, since there appears to be no 
specificity for turret material in Geolycosa (Wallace, 1942). 
Nearly all Geolycosa observed in the lab readily used artificially 
constructed burrows. Field observations of dispersing G. turricola 
(Miller and Miller, in prep.) indicate that over one half of burrows 
constructed by dispersing G. turricola spiderlings were built within a 
surface crack or depression. The results presented here also indicate 
a preference for burrowing when a surface irregularity is present. 
Surface cracks and crevices could provide protection from pred- 
ators and thermoregulatory advantage during the initial phase of 
