1988] 
Binder — Aggression in Heterotermes 
133 
groups of H. aureus penetrated, invaded, and attacked another col- 
ony similarly to foraging groups with soldiers, so that the actual 
contribution of a soldier’s cuticular or glandular substance to the 
increased excitement of the termites is uncertain. 
Complex behavior followed paired and multi-termite contacts in 
H. aureus. After encounters of paired termites from the same col- 
ony, the soldier or both the soldier and the worker made a few 
V.O.M.’s. Most V.O.M.’s, however, occurred during intercolony 
pairings, so it may be an alarm signal as suggested by Howse (1965). 
Workers were responsible for the initial intercolonial discrimination 
in simulated foraging experiments and then transmitted a warning 
via vibrational signals (V.O.M.’S) to the remainder of the colony. 
Worker V.O.M.’s are probably important cues to “call” soldiers to 
the area of contention. The source and the identity of the discrimi- 
nation cue (i.e. cuticular chemicals or complex behavior) is still 
unknown. 
Soldiers and workers behaved differently when given similar 
experimental treatments. A worker confronted with an immobilized 
alien soldier attacked. A soldier confronted with an immobilized 
alien worker did not immediately respond aggressively. The soldier 
may not have recognized the worker as “different” or immobiliza- 
tion prevented worker behavior critical for discrimination. Soldiers 
respond to cuticular and/or secretory substances in paired encoun- 
ters but were more likely to acknowledge vibrational cues during 
simulated foraging. H. aureus soldiers in normal foraging condi- 
tions may be relegated to a defensive/ offensive role as observed in 
other termites (Prestwich, 1984; Stuart, 1969; Thorne, 1982) and 
may not participate in intercolonial encounters until summoned by 
the workers giving vibrational signals. 
Workers and soldiers have different roles in overall colony 
aggression. Workers made initial contact with other colony members 
in simulated foraging experiments. They then triggered a sequence 
of events which recruited soldiers to the area of confrontation, 
widened the orifice between colonies, and were first to invade new 
territory. Workers were also aggressive in the absence of soldiers. 
The worker’s primary role in intercolony contacts, agonistic behav- 
ior, and defense has been described in Nasutitermes corniger 
(Thorne, 1982). The N. corniger workers attack soldiers vigorously, 
biting the legs and abdomen and H. aureus workers behave sim- 
ilarly. Soldiers that penetrated to the other colony area in simulated 
