86 
Psyche 
[March 
Table 3. Frequency distribution of group size in Metepeira spinipes colonies in low 
willows (Salix sp.). 
Group Size 
Observed 
Frequency 
Truncated 
Poisson 
Truncated 
Negative 
Binomial 
1 
8 
0.58 \ 
5.16 
2 
2 
244 \ 24 , 
3.26 
3 
3 
.686 t 
2.42 
4 
0 
1.44 / 
1.93 
5 
3 
2.42 
1.60 
6 
2 
3.39 
1.36 
7 
1 
4.080 
1.19 
8 
3 
4.285 
1.04 
9 
0 
4.000 
.93 | 
> 1.76 
10 
0 
3.360 
,83| 
11 
0 
2.57 
.75 1 
) 1.43 
12 
1 
1.00 
.68 | 
1 
13 
1 
1.16 
.62 1 
S 1.19 
14 
0 
.69 \ 
.57 1 
1 
15 
1 
— 1 
.53 | 
1 
16 
0 
( 1.51 
i 1.46 
17 
0 
.45 
\ 
18 
0 
— ( 
■ 42 i 
19 
0 
1 
.39 ( 
1.17 
20 
0 
— 1 
.36. 
) 
>20 
6 
6.06 
31 
X 2 = 79.36 
X 2 
= 16.02 
p < .005 
.4 < p < .5 
related to its energy needs and to the accessibility of prey (based on 
prey abundance and microclimatic stress limits on prey catching 
time) in a habitat. An energy-based territorial system might be part 
of a hypothesis generated to explain the evolution of social phenom¬ 
ena in spiders like M. spinipes. In habitats where accessibility to 
prey is high, territory size and inter-individual distance would be 
reduced, and populations would be large. If available web sites 
(providing architectual support for a 3 dimensional web as in soli¬ 
tary Metepeira ) were limited, selection would favor individuals ca¬ 
pable of living in an aggregated state. Behaviors favoring group 
occupation of web sites (increased tolerance of conspecifics, interat¬ 
traction) would be selected for, although behaviors associated with 
