1981] 
Carlin — Polymorphism in Oreetognathus 
241 
food. Alternatively, the medias may have been killing flies as 
trespassers approaching the nest too closely, rather than as prey, 
whereupon minor foragers picked up the remains. Majors could not 
leave their post at the entrance to engage in defense of the nest 
vicinity without exposing the opening to invaders. Besides, the 
bouncing strategy would be less effective in the open; it requires an 
invader to walk directly into the defender’s mandibles. 
Callow workers being easily recognizable by their lighter body 
color, the repertories of age groups within castes were examined for 
age polyethism. Callows exhibited fewer categories of behavior than 
older adults. As in Daceton and many other ant species (Wilson 
1971) they tended to concentrate on safe, in-nest tasks. Callow 
majors were notably more involved in brood care than older majors. 
As Brown (1957) had reported the genus to be nocturnal, 
observations were taken both during the day and, under red light, at 
night. Most foraging did indeed occur at night, but the ants engaged 
in a greater total number of acts, in more behavior categories, 
during the day, due to a diurnal rise in brood care and in-nest 
maintenance activity. This result suggests that more complete 
behavioral repertories can be compiled in the laboratory by studying 
ants during their periods of “inactivity”, when they are not investing 
so much of their effort in foraging. 
Discussion 
Polymorphic workers of Oreetognathus versicolor exhibit, all in 
all, a fairly elementary division of labor: Minor and media reper- 
tories are predictably similar, while majors constitute a distinct caste 
on behavioral as well as morphological grounds. The minor size 
class contributes most to in- and near-nest activity, including prey 
retrieval; the medias have a somewhat greater tendency to perform 
out-of-nest tasks and care for large brood; and the majors defend. 
Even if the medias are capturing prey and dropping it for minors 
to bring in, the resemblance to the polyethism pattern of Daceton is 
convergent at most. Daceton majors, not minors, return prey to the 
nest; Oreetognathus majors are bouncers. Daceton minors are 
restricted to brood care, while medias perform in-nest processing 
and refuse disposal (Wilson 1962); Oreetognathus minors attend all 
these tasks. The polyethism of O. versicolor is entirely unrelated to 
that of Daceton , having apparently arisen de novo along with its 
secondary polymorphism. 
