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Psyche 
[Vol. 90 
A total of 446 insects representing 6 orders were taken from 320 
webs of A. tuonabo. Approximately 95% of these insects belonged 
to those 5 prey categories which were most abundant in the sticky 
trap samples. Consequently, analysis of both web and spider selec- 
tivities will focus only upon these groups. In addition, since the 
composition of the flying insect fauna did not much vary with 
height, both the data regarding prey availability and diet were com- 
bined over all heights. 
Web selectivity values did not differ greatly from zero for beetles, 
nematocerous Diptera, or parasitoid Hymenoptera (Table 1). Non- 
nematocerous Diptera, however, comprised a small proportion of 
the web contents relative to their proportion on the traps. Con- 
versely, ants represented a large proportion of the web contents 
relative to their proportion on the traps. 
Aside from nematocerous Diptera, A. tuonabo were observed to 
consume prey types in proportions roughly equal to their propor- 
tion in the web (Table 2). Spider selectivity values for beetles, ants, 
non-nematocerous Diptera, and parasitoid Hymenoptera were all 
less than 0.20 (absolute value). In contrast, the Es value for nema- 
tocerous Diptera was large and negative. 
Figure 4. Vertical distribution of A. tuonaho and available prey. Heights of 
hub-resting spiders were measured to the nearest cm and then placed into 0.3 m 
intervals. Values for prey represent the total number of insects captured on 10 sticky 
traps suspended at a particular height. See text for details of sampling method. 
