20 
Psyche 
[March 
SPIDER BODY (MODEL) TEMPERATURE (°C) 
Figure 4. Number of Argiope trifasciata ballooning as a function of body (model) 
temperature. 
lings. Residence time by spiderlings on communal tangles was 
somewhat longer in early May than in late May (Table 1). Com- 
puting mean residence time (in days) from the data in Table 1, re- 
veals 7.5 days for the spiderlings emerging on 10 May, 8 days for 
11 May, 5 days for 14 May, 2.3 days for 19 May, and 4 days for 
22 May. 
Richter (1970) has stated that dispersal by spiders normally oc- 
curs on days that are unusually warm and calm for the time of 
year. In the same study, he demonstrated that a wolf spider, Par- 
dosa purbeckenis F. O. B. Cambridge exhibited aeronautic be- 
havior when laboratory air temperatures were varied between 18° 
and 34° C. The percentages of aeronautic behavior for each tem- 
perature range he used (which I calculated from his Table 4) were 
6.9% (18-19° C), 34.8% (28-29° C) and 36.4% (33-34°C). In 1975, 
20 of the 24 A. trifasciata spiderling masses dispersed on sunny 
days (see Table 1). Thus, it appears that dispersal in Argiope is 
influenced by climatogical factors, and in particular temperature. 
In addition to these findings, Duffey (1966) in monitoring winter 
