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[Vol. 95 
penetrated if there was a second encounter. When the worker con- 
tacted the head of an immobilized soldier there was repeated move- 
ment of the worker’s mandibles but no penetration of the heavily 
armored soldier head capsule. Eventually the soldier’s antennae 
were snipped off just above the scape or the labrum was damaged. 
Simulated foraging experiments 
Four experiments were completed. Experimental and control 
trials were made on October 1, 1986. The experimental group con- 
tained 300 workers and 15 soldiers (undyed) on one side of the 
balsawood barrier and 500 workers and 15 soldiers (dyed) from 
another colony on the other. A similar control group contained 500 
workers and 15 soldiers from the same colony on each side with one 
of the groups dyed. The soldier/ worker ratio in these experiments 
was similar to soldier/ worker ratio of H. aureus foraging groups in 
the field (Haverty, 1977). After the normalization period, workers of 
both experimental groups began removing bits of the wood parti- 
tion. Upon antennal contact with alien workers, some workers 
abandoned their activity, retreated backwards out of the hole, and 
began Vertical Oscillatory Movement (V.O.M.) (Howse, 1964). 
Many termites became agitated, moved rapidly, and soldiers clus- 
tered around the breach in the barrier (Figure 3). The soldiers in the 
hole impeded tunneling, but a few workers excavated more wood. 
Some soldiers arched the abdomen, perhaps releasing a sternal 
gland substance. After 30 minutes, 2 dyed workers penetrated to the 
side of the undyed colony and within 15 minutes more than 100 
dyed termites (both workers and soldiers) had migrated to the 
undyed termite side while only 55 undyed termites moved to the 
dyed termite area. After 24 hours only 5 dyed individuals remained 
alive. Meanwhile, control groups had penetrated at about the same 
time as the experimentals but no agonistic behavior was observed. 
After 24 hours, members of the dyed and undyed control groups 
were completely mixed. These results demonstrated that intercolony 
contact of large foraging groups led to aggression which was not 
terminated at colony boundaries. The soldier’s contribution to the 
successful invasion was not clear, so two more tests were made on 
November 1, 1986. One test contained 500 workers from different 
colonies on either side, with no soldiers. All the termites were dead 
after 24 hours. The coincident trial contained 500 workers on either 
side but one side contained 8 soldiers (dyed) while the other side 
contained 25 soldiers (undyed). When the hole was large enough, 
