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Psyche 
[Vol. 95 
Simulated foraging experiments 
Termites are generally found in foraging groups when observed in 
the field. Field conditions were simulated in the laboratory with a 
glass arena containing a balsawood barrier to separate termites 
from different colonies (experimental) or from the same colony 
(control) (Fig. 1). One group of termites was dyed with Sudan Red 
7B by the method of Lai et al. (1983) before each experiment. Large 
groups (approximately 500) of mixed soldiers and workers were 
placed on each side of the arena. The termites required approxi- 
mately 1 hour to start foraging behavior and nearly 8 hours to 
penetrate the barrier. Termite behaviors were documented and 
examined using high magnification video recording equipment. 
Results 
Soldier vs. soldier interactions 
When two soldiers from different colonies were paired in an 
arena, each would walk until there was contact. These encounters 
resulted in a brief to extended period of antennation, followed by 
the retreat of one or both, opening and repeated snapping of the 
mandibles. A fatal snap resulted when the mandibles penetrated the 
head, thorax, or abdomen. Snaps which severed only an antenna or 
leg were not fatal. Soldiers that had delivered a fatal snap made 
several additional contacts, an occasional snap, and moved away as 
if no longer considering the “enemy” a threat. There were further 
contacts by the victorious soldier but no snaps. The mechanism by 
which the soldier made this decision is unknown. 
Soldier vs. worker interactions: arena size 
Intracolonial termite pairs of soldier and worker had a mean 
number of encounters/ minute (± standard error) of 3.0 ± 0.2 at 1.5 
cm 2 , 2.5 ± 0.2 at 3.0 cm 2 , 2.2 ± 0.2 at 4.5 cm 2 , and 1.6 + 0.2 at 6.0 
cm 2 (Figure 2a). Intercolonial encounters between soldier and 
worker also decreased with an increase in arena size. The mean 
number of encounters/ minute (± standard error) for intercolony 
pairings was 2.0 ± 0.2, 2.2 ± 0.2, 1.7 ± 0.2, and 1.4 ± 0.1 at arena 
sizes of 1.5, 3.0, 4.5, and 6.0 cm 2 respectively (Figure 2a). While 
there was no aggression during intracolony pairings, most intercol- 
ony pairings resulted in soldier displays of aggression, including 
attack posture (open mandibles against the substrate), numerous 
snaps of the mandibles, and rapid retreats. At every arena size more 
