FACTORS INFLUENCING WEB SITE RESIDENCE TIME 
OF THE ORB WEAVING SPIDER, 
MICRA THEN A GRA Cl LIS. 
By Margaret A. Hodge* 
Department of Entomology, University of Georgia, 
Athens, Georgia 30602 
Introduction 
The word “habitat” may be used with varying degrees of preci- 
sion. When describing the finer details of where an animal lives, the 
term microhabitat is often used to distinguish this from the particu- 
lar community or ecosystem. Examination of microhabitat selection 
involves determining the factors which influence preference for a 
certain site. Many factors have been shown to affect the length of 
time that spiders will spend at a particular web site. Physical settings 
providing protection against web destruction by wind or rain may 
be important (Eberhard 1971; Enders 1976; LeSar & Unzicker 1978; 
Marson 1974). Prey abundance, as well as factors relating to prey 
detection and capture sucess, are also important in microhabitat 
selection (Riechert & Tracy 1975; Riechert 1976). Because food 
resources have been demonstrated to have a large impact on indi- 
vidual fitness in several spider species (Deevey 1949; Turnbull 1965; 
Miyashita 1969; Hagstrum 1970; Kessler 1973; Greenstone 1978; 
Kajak 1978; Morse & Fritz 1982; Wise 1975) web site selection 
should be expected to be strongly linked to food supply. Studies 
which have examined the dynamics of prey availability have impli- 
cated web site relocation as a proximate mechanism for food supply 
enhancement (Turnbull 1964; Riechert 1978; Olive 1982; Janetos 
1982). 
Micrathena gracilis (Walckenaer) is an orb weaving spider com- 
mon to deciduous forests throughout northeastern North America. 
These spiders characteristically build webs spanning large open 
areas between vegetation (90-250 cm). Certain individuals may 
♦Present Address: Department of Biological Sciences, M.L.#6, University of 
Cincinnati, Cincinnati, Ohio 45221 
Manuscript received by the editor July 24, 1987. 
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