1987] 
Hodge — Residence time of Micrathena 
365 
direct sunlight and/or assuming a thermoregulatory position 
(Robinson & Robinson 1979), and the condition of the web (extent 
of damage, if any). These observations were made from approxi- 
mately 1 m from the web, to avoid disturbing the spider. Thus it was 
not possible to measure prey lengths. However, if a spider captured 
a large prey item it was likely to feed for 2-3 hours (personal obser- 
vation). This was recorded as 2-3 observations of feeding in the 
hourly censuses. Therefore, the feeding rate, equal to the number of 
feeding observations, is an estimate of the prey consumed by a 
spider at a particular web site. Other information, such as molting, 
mating activity, predation, and intra- or interspecific interactions 
were also recorded. The study was terminated on 11 August, 1984. 
Results 
The average web site residence time was 6.7 days (S.D. = 5.29 
days). Residence times were compared to values expected from a 
negative exponential distribution, which indicates random processes 
in time (Bailey 1964; Ross 1970). The distribution of observed resi- 
dence times was significantly different from that expected by a ran- 
dom process (x 2 = 1889; p 0.001; Fig. 1). 
A total of 2131 web observations were made by checking spiders 
at hourly intervals. Of this total, there were few observations of 
sun-exposure or thermoregulation, and of these, few were followed 
by web site relocation (Table 1). A much greater percentage of the 
total number of relocations occurred following web destruction 
and/or were preceded by days of scarce prey (Table 1). There were 
36 web site relocations during the study, and 34 of these were pre- 
ceded by a day of either zero or one feeding observation, and/or 
web destruction by wind or rain. Only two relocations were not 
associated with either of these variables. Eighteen of the web reloca- 
tions were preceded by web destruction. Thirteen of these 18 were 
simultaneously associated with low feeding rates. Sixteen relocations 
were associated with low feeding rates alone. A Chi-square test for 
independence led to acceptance of the null hypothesis that web relo- 
cation was not differentially influenced by either low prey levels (0- 1 
prey observations/ day) or web destruction, or even by a combina- 
tion of the two (Table 1; x 2 = 2.16, p > 0.50), i.e., both factors 
seemed to have a similar contribution to the decision to move. A 
feeding rate, equal to the number of feeding observations divided by 
