1985] 
Pamilo, Crozier, & Fraser — Rhytidoponera 
227 
Table 6. Behavioral comparison of carrier and recruit ants collected during inter- 
nest movement: number of observation periods (out of nine) that ants were seen in 
the lit halves of choice chambers. Each series of observations on 10 individual ants in 
the two categories has been ranked. 
Ant rank 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
Carriers 
0 
4 
6 
7 
7 
8 
8 
8 
9 
9 
Riders 
1 
1 
2 
2 
4 
5 
5 
6 
8 
9 
doned in 1983 anyway because the ants showed no interest in mut- 
ton baits during our visits then. We chose not to use the method 
described by Haskins and Haskins (1983) for tests with R. metallica, 
in which individual ants from different nests are placed together in 
glass containers, because in that case both ants have been removed 
from their natural surroundings. Instead, we picked up an ant from 
one nest, grasping it by a mid-femur using forceps, and held it in the 
entrance of a target nest until four residents had examined it. If any 
of these attacked the transferred ant, the result was taken as a 
rejection of this ant. Five ants in all were used sequentially for each 
test, and, wherever allowed by the numbers of ants available, tests 
were made reciprocal. Because our method creates an artificial 
situation and the response at the nest entrance can be largely 
induced by the introduced ant, we also tested the method by making 
a control test at each nest, returning ants to their home nest: these 
ants were never attacked. 
During any one test, results were usually fairly unequivocal. Even 
when ants attacked the forceps vigorously, they often ignored the 
transferred ant. However, we found a high degree of variation 
between replicates (Table 7), which may reflect differences in the 
responsiveness of the ants under varying environmental conditions 
(which we could not readily control). Nevertheless, some patterns 
do emerge. Thus, nest 61 was markedly more hostile to the “carry- 
ing” nests in September than in November, reflecting the significant 
turnover of ants between those times. Similarly, nest 60 shows ele- 
vated acceptance levels compared to other nests. 
The results at nest 55 may have been affected by the fact that the 
mound was destroyed by some animal (probably a kangaroo) at the 
beginning of our experiments in September and the ants were busy 
rebuilding it. 
