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[Vol. 95 
exhibited at least one of the following behaviors: flying; running in 
circles; or mounting other males. Both glands from each queen were 
tested (except when the reservoir or mandible broke during dissec- 
tion), followed by a similar test with the remaining head. The inter- 
val between all tests was 5 min. Glands and heads from 10 different 
queens (5 alate, 5 dealate) were used. Finally, we also tested two 
dissected maxillary and postpharyngeal glands, as well as squashed 
heads from two workers and two males. Unfortunately, by the time 
this laboratory study was established, it was the end of the repro- 
ductive season. As a result, the same 7 Polyergus males had to be 
used for all tests. 
Results 
Table 1 shows the results for the 10 queens and 7 males. The 
proportion of males active before squashing the mandibular gland 
reservoir was 0.02 (summed over all trials; n = 126). Afterwards the 
proportion was 0.84. For tests with squashed queen heads after 
removal of the mandibular glands, the proportion of males active 
was 0.27 (n = 56 cases). The latter activity may be due to occasional 
leakage of mandibular substance into the head during the dissec- 
tion. The behavior of the males during positive tests was very similar 
to their responses to crushed queen heads in the field. Although 
sustained flight was impossible in the small plastic enclosures, the 
squashed mandibular glands immediately caused the males to run 
excitedly in circles inside the box, and they occasionally even 
mounted each other. The mandibular glands of dealate queens 
(which were collected near raiding columns or from Polyergus nests) 
were as effective in exciting males as those of alate queens. Finally, 
no activity by the experimental males was elicited either by dissected 
maxillary and postpharyngeal glands, or by squashed heads from 
two workers and two males. 
Discussion 
The mating behavior of P. breviceps queens is ecologically similar 
to the “female calling syndrome” that is commonly found in primi- 
tive and socially-parasitic ants (Holldobler & Bartz, 1985). A prin- 
cipal characteristic of this process is that new queens do not disperse 
widely; instead, they remain close to their nest of origin and secrete 
male-attractant pheromones. Also typical of this behavior is the 
production each year of relatively few reproductives, and nuptial 
