1984] 
Gordon — Pogonomvrmex bad i us 
261 
Table 2D. Behavior of callows while convening 
Activity 
when 
Marked 
F 
Subsequent Activity 
NM PT 
MW 
CN 
Marked 
26 
17 
63 
74 
** 
385 
Unmarked 
2290 
14382 
4664 
9731 
15601 
CN 
Dev. for Exp. 
-1.7 
-155.2 
-6.5 
-43.3 
+ 193.8 
% Dev. 
6 
90 
12 
37 
101 
F= Foraging; NM = Nest Maintenance; PT = Patrolling; MW = Midden Work; CN = 
Convening. 
Convening of exterior workers is observed much more often in the 
laboratory than in the field. Convening includes resting and mutual 
grooming. It probably serves a thermoregulatory function as well, 
because convening ants in laboratory colonies always gather in the 
warmest place on the terrarium surface, directly underneath a lamp. 
Convening has been observed in field colonies of Pogonomvrmex, 
but only rarely (MacKay 1981; Gordon 1983b, 1984a, b). It is 
possible that, in the field, convening is usually done inside the nest 
where conveners would be less subject to predation. 
The results of this study, summarized in Table 2C, suggest the 
diagram depicted in Figure 1. The diagram shows how role may 
depend on worker age in exterior workers of P. badius. It should be 
emphasized that the diagram is hypothetical, pending further investi- 
gation, and that it rests on two assumptions. In keeping with results 
on many other species (Wilson 1971), it is assumed that younger ants 
first work inside the nest, then work outside the nest for the 
remainder of their lives. Another assumption is that in the laboratory 
experiments reported on here, the death rate of ants in a particular 
activity depends on their age rather than on the hazards or energetic 
costs associated with their activity. Convening ants are clearly less 
active than ants in the other four activities (see Table 1). However, 
there is at present no empirical basis for distinguishing the other four 
activities in terms of the energy expended performing them. 
Ants doing midden work and patrolling are shown as the oldest in 
Figure 1 , because ants marked while doing these activities died within 
