THE “EDGE EFFECT” IN SCHIZOCOSA OCREATA 
(ARANEAE: LYCOSIDAE): 
A REASSESSMENT 
By Alan B. Cady 1 , William J. Tietjen 2 , and George W. Uetz 3 
Introduction 
The relationship between local spider distribution patterns and 
environmental factors has been studied in a variety of species 
(N0rgaard 1951; Dondale et al. 1969; Hallander 1970; Edgar 1971; 
Riechert 1974, 1976; Uetz 1976; Dondale 1977). Aspey (1976) stated 
that Schizocosa ocreata (Walckenaer) (formerly crassipes; Dondale 
and Redner 1978) was found in aggregations along a woodland-field 
ecotone, and suggested that unique microclimatic conditions and 
social interactions among conspecifics occurring within this area 
resulted in an “edge effect” for this spider’s distribution. He termed 
S. ocreata an “edge” species, implying it was found almost exclu¬ 
sively along ecotones. We were skeptical of Aspey s (1976) conclu¬ 
sions, since previous literature and prior experience with this species 
led each of us to the separate conclusion that S. ocreata is a forest¬ 
dwelling spider (Kaston 1948; Dondale and Redner 1978; Uetz 1976; 
Cady (in prep.)). In addition, Aspey’s (1976) survey for S. ocreata 
appeared incomplete, as he did not report sampling within the 
adjacent woodland or field. Considering Aspey’s (1976) elaborate 
behavioral arguments based on assumptions about the distribution 
of this species, we felt further study was necessary. 
Methods 
The study site was approximately 3.5 km west from Aspey’s (1976) 
site. Three areas were sampled: A mixed hardwood deciduous 
woodland ( Quercus sp., Liriodendron sp., Fraxinus sp., Fagus sp.), 
the adjoining ecotone, and an open goldenrod-thistle field ( Solidago 
sp., Cirsium sp.). Spiders were sampled by twelve pitfall traps of the 
type described by Uetz and Unzicker (1976). Three were set in the 
1. Dept, of Zoology. Ohio University, Athens, Ohio45701 (Present Address: Dept, 
of Zoology, University of Tennessee, Knoxville, Tenn. 37916) 
2. Georgia College, Milledgeville, Georgia 31061 
3. Dept, of Biological Sciences, Univ. of Cincinnati, Cincinnati, Ohio 45221 
Manuscript received by the editor January 20, 1981 
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