120 
Psyche 
[June-September 
Table 2. Group fanning of Protopolybia exigua to odors. 
Group Fanning 
Tests 
Trials 
N 
% 
Crushed single ants 
Aztec a sp. 
15 
1 
7 
Camponotus sericeiventris 
23 
6 
26 
Eciton burchelli 
40 
28 
70 
Eciton hamatum 
14 
10 
71 
Ectatomma tuberculatum 
9 
0 
0 
Paraponera clavata 
13 
0 
0 
forceps control 
27 
2 
7 
Ant extracts 
Eciton 
18 
12 
67 
Monads bispinosa 
6 . 
0 
0 
Neivamyrmex pilosus 
8 
0 
0 
Nomamyrmex esenbecki 
10 
1 
10 
solvent, methylene chloride 
27 
0 
0 
Chemicals 
citral 
14 
0 
0 
formic acid 
11 
8 
73 
4-methyl-3-heptonone 
6 
0 
0 
paper control 
44 
0 
0 
group fanning. The data summarized in Table 2 show that of all the 
crushed and extracted ants, chemicals, and controls tested, only the 
2 Eciton species, Camponotus sericeiventris, and formic acid elicited 
group alarm in significant numbers of tests (P < .005, as determined 
by chi-square analysis). The response of C. sericeiventris, was signif¬ 
icantly lower than to the Eciton species and the synthetic formic 
acid (P < .005). Most likely, formic acid which occurs in C. sericei¬ 
ventris causes the alarm response of the wasps to that ant species as 
well. The 0.5 p\ of synthetic formic acid tested falls within the range 
of a single-ant amount (Stumper 1952), but the odor seemed subjec¬ 
tively stronger than the crushed C. sericeiventris. This may explain 
why the synthetic formic acid evoked group fanning more effectively 
than the crushed ant. 
I conclude that Eciton odor is highly effective in eliciting alarm 
from P. exigua. Together, the 8 species of crushed ants and the 3 
synthetic ant pheromones tested represent a selection of odors from 
all 6 Neotropical ant subfamilies (Brown 1973). If the alarm to C. 
sericeiventris is due to formic acid then only one substance other 
than Eciton odor actually evoked alarm. Although P. exigua does 
not respond exclusively ‘to army-ant odor, the odor is a relatively 
specific alarm cue. 
