1987] 
Uetz & Hartsock — Micrathena gracilis 
107 
SIZE CLASS (mm) 
U* ATTACK 
^‘IGNORE 
□ =ESCAPE 
Figure 2. Size frequency distribution of insects attacked or ignored by spiders, 
showing the increased frequency of attacks on larger sized insects. Escapes shown 
occur after the 3 second “stick” criteria. 
though it may have oriented toward and plucked at the insect in the 
web. A capture was recorded when the spider actually had control of 
the insect in its chelicerae. If the spider voluntarily discarded the 
insect, a reject was recorded. If the spider wrapped the prey item in 
silk after capture, a wrap was recorded. Finally, if it fed on the insect 
during the observation period, a feed was entered. 
A comparison was also made of the insects captured by the web 
and those captured by a web-mimicking artificial sticky web trap 
(ASW) modified from a design reported by Uetz & Biere (1980). 
ASW trap frames were constructed out of 3/8 inch by 3/4 inch 
aluminum window screen frames (Custom Aluminum Products, 
Cincinnati, Ohio), with an area slightly larger than M. gracilis webs 
(38 cm X 38 cm). Clear, monofilament nylon thread woven onto a 
wooden loom surrounding the frame was held in the grooves of the 
window screen frame with spline in order to permanently secure the 
thread to the frame. This clear thread was 0.2 mm in diameter and 
could be woven into any desired mesh size. The mesh sizes used 
closely approximated those of M. gracilis (1 to 2 mm between 
