1983] 
Haskins & Haskins — Rhyticloponera mefai/ica 
165 
results generally confirmatory of those reported earlier, though with 
somewhat higher levels of aggression than the year before. Thus, of 
fifty-one pairs tested, 37 showed full compatibility, 8 exhibited 
“startle” reactions, in 2 cases there was momentary seizure with 
immediate release, and in 4 cases there was violent attack. Thus 
noncompatibility between the members of Moieties B' and B" 
maintained for a year separately on the same diets, was virtually 
negligible, while that of moiety A and the other pair, maintained on 
different diets, was generally confirmatory of earlier findings: signif- 
icantly higher but still, after two years of separation, not nearly 
comparable with reactions toward the members of another, widely 
separated population taken near Sutherland, N.S.W., as earlier 
reported. From all these tests it might have been concluded that, as 
indicated by pair compatibility encounters, genetic factors were sig- 
nificant but were overlain by a measureable diet factor. In fact, the 
situation now appears more complex. 
Tests with whole nests 
On June 27, 1982, a single nest, housing 70-100 workers of the 
second moiety {B') (nests consisted of earth-filled Lubbock-type 
glass “sandwiches” stacked) was transferred to the arena of the first 
moiety {A). The introduced nest was placed as far away as possible 
from the stacked A nests in the arena. Arenas used throughout were 
fabricated from 5/8 cm. thick transparent polyster sheets glued 
together to form lidless boxes of dimensions 59.5 cm. X 44.5 cm. X 
18.5 cm. covered with screening set in wooden frames, and lined 
with white paper. 
The reaction was immediate, violent, and virtually universal. 
Massed workers from A entered the introduced B' nest in force, show- 
ing unequivocal hostility, seized and dragged out almost the entire B 
population, ultimately killing a large fraction of them. The struggle 
went on for two days, and resulted in the apparent total occupation 
of the B' nest by A workers. Subsequently, this nest was fully incor- 
porated into the A colony. Thus the reaction in this experiment was 
in dramatic contrast to the very limited aggression shown in the 
pair-tests. 
It remained to determine whether similar behavior would occur 
between moieties B' and B'\ which had been maintained on the 
same diets and, as described, had exhibited nearly complete compat- 
ibility in the pair-tests. 
