1985] 
Moffett — Behavioral notes on Acanthomyrmex 
175 
ignored the intruders or moved away. Thus the majors were appar- 
ently responding to nest intrusion. After a period in which the 
corpse was ignored, the minors found and began feeding on the 
embiopteran. 
Acanthomyrmex ferox. Defensive behaviors of workers of Acan- 
thomyrmex ferox confronted with Lophomyrmex were similar to 
those described for A. notabilis : both majors and minors antennated 
the intruder rapidly and then attempted to bite it, or to swing their 
gasters beneath their bodies in the direction of the intruder, or both. 
As in A. notabilis , the gaster tip was usually brought into contact 
with the intruder, at least intermittently: examination of photo- 
graphs indicates that the ants were extruding their stings. Acantho- 
myrmex notabilis workers have the sting apparatus greatly reduced 
relative to the size of the ant (Kugler 1978), and this is also true of 
A. ferox; however, this appears not to preclude a defensive function. 
Discussion 
Colony size. Acanthomyrmex colonies appear to be small: the 
A. notabilis and A. ferox colonies apparently both consisted of less 
than fifty individuals. In the A. notabilis colony, 7.5% (or three out 
of 40) of the workers were majors, while this figure is 4. 1% (two out 
of 49) in the ferox colony. Colonies of A. notabilis from Mt. Klabat 
collected by William L. Brown, Jr. (pers. comm.) also contained 
about 40-50 workers, including 1-3 majors. 
In both Acanthomyrmex notabilis and A. ferox , workers fre- 
quently held immatures passively in their mandibles for long peri- 
ods, even during intervals of colony quiescence. Similar behavior 
has been observed for workers of the trap-jawed formicine ant 
Myrmoteras toro (Moffett, in press). The brood holding behavior in 
both cases seems to represent a means of insuring that workers can 
rapidly disperse with brood whenever the colony is disturbed. This 
is a particularly useful strategy for ants nesting in exposed sites 
where disturbances are common. As in the A. ferox colony described 
here, the Myrmoteras colony, which consisted of 22 workers and 
one queen, had been nesting between leaves lying loose within leaf 
litter on the forest floor. 
Another common trait of Acanthomyrmex, Myrmoteras toro , 
and many other ants with small colonies (including colonies of 
