NOTES ON THE BEHAVIOR OF THE DIMORPHIC ANT 
OLIGOMYRMEX OVERBECKI* 
(HYMENOPTERA: FORMICIDAE) 
By Mark W. Moffett 
Museum of Comparative Zoology, 
Harvard University, 
Cambridge, Massachusetts 02138 
Species of the myrmicine genus Oligomyrmex are common in 
tropical Asia, although the ants are easily overlooked because of 
their small size and inconspicuous activities. The genus is of special 
interest because of the well developed worker dimorphism shown by 
all species. Some natural history information is available on Ere- 
bomyrma (Eidmann, 1936; Wilson, 1962, 1986), the American sister 
group to Oligomyrmex which has only recently been resurrected 
from synonomy with that genus (Wilson, 1986). However, the natu- 
ral history of Old World Oligomyrmex ants has never been 
investigated. 
I have made preliminary behavioral observations on a colony of 
Oligomyrmex overbecki Viehmeyer collected in Singapore (fig. 1). 
This species is clearly one of the world’s smallest ants, with minor 
workers having head widths of 0.29-0.32 mm, while the “miniature” 
majors have head widths of 0.42-0.45 mm. 
Materials and Methods 
The study colony was collected on the grounds of the Botanic 
Gardens of Singapore, under bark still firmly attached to the trunk 
of a large Eugenia grandis tree (Myrtaceae), within 50 cm of ground 
level. The colony was placed in a plastic box 20 X 10 X 7 cm deep, 
with a moistened paper-mache bottom gouged towards one end 
with several small, shallow chambers, which were then covered with 
a sheet of glass. The ants moved into the artificial nest chambers, 
where they could readily be observed through the glass. 
* Manuscript received by the editor January 26, 1986 
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