PATCHY DISTRIBUTIONS OF ANT SPECIES IN 
NEW GUINEA RAIN FORESTS 
By Edward 0. Wilson 
Biological Laboratories, Harvard University 
While recently engaged in field work in New Guinea the 
author had several excellent opportunities to study local 
areal distribution of rain forest ants. During one three- 
week period in April, 1955, a walk was made from Fin- 
schhafen, on the eastern tip of the Huon Peninsula, west 
for a distance of 45 kilometers through the midmountain 
rain forests of the Dedua-Hube regions to Tumnang and 
Laulaunung, thence south for thirty kilometers to Butala 
on the southern coast. In the vicinity of Lae intensive collec- 
ing was conducted over a distance of twelve kilometers in 
recent" y continuous lowland rain forest within the triangle 
formed by Didiman Creek, Bubia, and the section between 
the Busu and Bupu Rivers. 
Areal distributions of individual species were found to 
be almost universally patchy, despite the external appear- 
ance of uniformity of the rain forest environment. Further- 
more, in the cases of species abundant enough to be studied 
in some detail, the patchiness seemed to obtain at two levels 
of distribution, which for purposes of description here will 
be referred to as “microgeographic” and “geographic”. 
Microgeographic patchiness. The species common enough 
to be studied in detail are also relatively adaptable, occurring 
usually in spots of variable canopy density (see below) and 
sometimes in more than one major forest type (e.g., Lepto- 
genys dimunuta (Fr. Smith), which ranges from medium 
lowland rain forest to dry, monsoon forest). In this respect, 
at least, they seem to be no more specialized than the ma- 
jority of temperate ant species. At the same time, they show 
definite preferences for certain local environmental con- 
Explanation of Plate 3 
Plate 3. Primary medium-aspect rain forest near the lower Busu 
River, Northeast New Guinea. A bulldozer trail cuts through the 
lower left hand corner of the picture. 
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