1987] 
Hodge — Orb weaving spider 
357 
Table 3. Mean and 
measured in each habitat. 
standard-deviation (S.D.) 
of environmental parameters 
Parameter 
Pine Stand 
Deciduous Stand 
Relative humidity 
Mean 
53% 
54% 
S.D. 
20% 
30% 
Temperature 
Mean 
U 
o 
m 
m 
32° C 
S.D. 
5° C 
3° C 
Prey/ Sticky Trap/ Day 
Mean 
7.2 
4.6 
S.D. 
2.4 
2.7 
Prey size (mm) 
Mean 
2.4** 
4.6** 
S.D. 
1.4 
2.9 
Attachment points <1 m 
Mean 
1.78 
0.70 
S.D. 
0.92 
1.05 
Attachment points 1-3 m 
Mean 
0.29** 
0.45** 
S.D. 
0.54 
0.62 
Attachment points >3 m 
Mean 
0.05* 
0.39* 
S.D. 
0.23 
0.59 
*significantly different; t-test, p < 0.01 
♦♦significantly different; t-test, p < 0.001 
1972; Robinson & Robinson 1974; Tolbert 1976; Carrel 1978). Dif- 
ferences in the canopy of pine and deciduous forests may affect the 
intensity of solar radiation reaching spiders in webs below. The 
deciduous woods had a much higher percentage of deciduous can- 
opy, which is more effective than pine canopy in providing shade. 
Biere and Uetz (1981) have shown that even within the forest, M. 
gracilis adjusts the orientation of the web to minimize intense solar 
radiation in open patches. They also found that spider body 
temperature was positively correlated with the amount of solar 
radiation striking the animal. It is therefore possible that heat stress 
(as indicated by thermoregulatory posturing) in the pine stand con- 
tributed to web relocation. Experiments with Micrathena schrei- 
bersi (Perty) by Robinson and Robinson (1974) showed that 
