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[Vol. 94 
Table 2. Distribution of canopy types in each of the two habitats (% area 
covered). 
Canopy type 
Pine Stand 
Deciduous Stand 
Open 
64% 
33% 
Pine 
30% 
5% 
Mixed 
2% 
5% 
Deciduous 
4% 
57% 
indicate no difference in humidity or ambient temperature between 
the deciduous forest area and the pine stand. It would therefore 
seem that if habitat selection was based on ambient temperature or 
humidity, spiders would have been equally likely to move from the 
deciduous forest to the pine stand. 
Prey availability, if different between the two macrohabitats, 
might provide a basis for macrohabitat selection. The sticky trap 
data indicate a significant difference in insect lengths between the 
habitats, suggesting that more biomass may be available in the 
deciduous forest. In addition, the higher frequency of web destruc- 
tion in the pine stand may have reduced the time available on the 
web (which reduces the time available for intercepting prey). How- 
ever, these data may not accurately reflect the prey which the spiders 
actually sampled, as the precision with which sticky traps represent 
prey intercepted by webs and captured by spiders is questionable 
(Castillo & Eberhard 1983). 
Habitat preferences based on structural characteristics are a fac- 
tor limiting the distribution of some spider species (Eberhard 1971; 
Colebourn 1974; Enders 1976). Hartsock (1983) suggests that such 
preferences may explain the different distributions of M. gracilis 
and Verrucosa arenata (Walckenaer) within the forest. The impor- 
tance of structural properties in construction and maintenance of 
webs may be similarly involved in this study. The length and posi- 
tion of the bridge thread, which is the basic foundation of the web, is 
controlled by the spatial distribution of attachment sites (vegeta- 
tion). Suitable attachment sites are vegetation between 1-3 m tall, or 
taller. This type of vegetation was significantly less abundant in the 
pine stand. The deciduous forest provided more attachment sites 
plus amelioration of destructive air currents (as seen by the lower 
percentage of web destruction in the deciduous area). 
Several studies have demonstrated that solar radiation can have 
profound effects on the behavior of orb weaving spiders (Krakauer 
