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[Vol. 85 
Figure I. Daily activity rhythms. 
The mean numbers of ants engaged in each activity are plotted as a function of 
time of day. Times shown are the usual observation times. Error bars show standard 
error of the mean. No error bar is present when the size of the error bar was smaller 
than that of the symbol for a point in the graph. 
as temperature and food availability. In P. badius, the five activities 
described here are performed by four distinct groups of ants (mid- 
den work and patrolling are done by the same individuals) (Gordon 
1983d). Whether there are intrinsic physiological rhythms causing 
these different groups to be active outside the nest in different 
numbers, depending on time of day, is a question still to be 
explored. 
Temporal patterns in overall activity level are known to exist in 
many species of ants. Further research on such species may reveal 
more detailed patterns of particular activities. Cognizance of such 
patterns is relevant to the design of further behavioral experiments. 
