1969] 
Hangartner — Solenopsis 
6l 
The first experiment showed that the behavior pattern just de- 
scribed can be released by trapped workers, females, males, and even 
brood (Table i). The positive result obtained with brood indicates 
that the “rescue” activity can be initiated by something more than 
stridulation of the trapped individuals, the mechanism in leaf-cutting 
ants (Markl, 1967). Stridulation can also be ruled out by trapping 
dead ants which have been killed by chilling just before the experi- 
ment. In series A, the dead workers were presented intact, whereas 
in series B, they were homogenized, transferred to a small piece of 
cotton and trapped in this way. In both cases the small pieces of 
cardboard were replaced after 20 hours and the experiment stopped 
after 44 hours. 
bigure 2 shows that the homogenized ants release a stronger dig- 
ging activity than the intact ones and that this activity increases with 
A (dead ants intact ) 
B (dead ants homogenized) 
20 h 
44h 
20 h 44h 
trapped ants alive 
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'M«8 
Figure 2. Comparison of the digging activity released by living and 
dead ants recorded after 20 and 44 h, respectively. Series A: Dead workers 
intact, Series B: Dead workers homogenized. The radius of the stippled 
areas represents the average digging response and the radius of the dashed 
circles indicates the range of the 10 experiments performed. 
