14 
Psyche 
[March 
Methods 
This study was conducted in April and May 1975, in a two hectare 
overgrown pasture in Loudon County, Tennessee; a complete de- 
scription of the study area is reported elsewhere (Tolbert, 1976). 
The study area is 3.2 kilometers (2 miles), west of Glendale com- 
munity. Spiderlings of two orb weaving spider species, Argiope 
trifasciata and Argiope aurantia, were observed after emergence 
from more than 50 egg sacs. The spiderlings from egg sacs were 
monitored for dispersal and related activities during daylight hours. 
Spider body temperatures were estimated by the use of a thermo- 
couple junction and associated cylindrical solder model of the same 
dimensions as a first instar spiderling (0.5 mm X 1.5 mm). Direct 
readout of model temperatures at dispersal height were recorded 
on an Esterline-Angus Continuously Recording Potentiometer. 
Wind speeds at dispersal height were measured with a Rimco 
miniature cup anemometer, stall speed 0.25 m/sec. 
Behavior Prior to Dispersal 
Unlike Argiope aurantia spiderlings, which emerge from an egg 
sac over a period of several days or weeks (Tolbert, 1976), Argiope 
trifasciata emerged in mass during the study period of April and 
May 1975. All spiderlings emerged from any given egg sac within 
a single day, usually within a period of one to two hours. This 
was confirmed by cutting open egg sacs from which spiderlings had 
recently emerged and checking for spiderlings that were left. An 
ethogram which summarizes the findings of this study on Argiope 
spp. dispersal behavior is depicted in Figure 1 . Individuals quickly 
constructed a communal tangle or communal web, which is a mesh- 
work of interlocking threads, by laying down draglines. Division 
of labor was not observed; each spiderling simply contributed a 
small amount of silk to the tangle. Spiderlings observed in 1975 
resided on such tangles for several days (x ± S. E. = 3.5 ± 0.52 
days) before dispersing. Valerio (1975) reports that the common 
house spider Achaeranea tepidorium (C. L. Koch), also spends 
three to four days in dense clusters on the maternal web before 
dispersing aerially. Communal tangle formation by Argiope au- 
rantia was less common. In the four instances where communal 
tangles were constructed by A. aurantia, the egg sacs had fallen 
to the substrate. Possibly a differing microclimate near the 
