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Psyche 
[Vol. 94 
(reported in Forel, 1928), and it has been assumed that group- 
raiding behavior occurs in the whole genus (Wheeler, 1936; Wilson, 
1958). The colonies of O. berthoudi are polydomous (Peeters, 1984). 
Natural Habitat and Methods 
This study was carried out in one locality in Mkuzi Game Reserve 
(north-eastern Natal, South Africa), during 1981-1983. Over 100 
working days were spent in the field. Mkuzi is semi-arid (Goodman, 
1981), with a hot humid summer from mid-September to the end of 
March. The rainfall is highly seasonal, peaking in February and 
lowest in June. The greatest variability in the mean monthly rainfall 
occurs during the dry winter months. The colonies of Ophthalmo- 
pone berthoudi occurred in open woodland with a grass component 
less than f%. The micro-distribution of these ground-dwelling ants 
is influenced by soil characteristics. They nest in sandy clay loam 
which is free-draining (i.e. no sub-surface clay pans). The surface is 
slightly capped and compacted; this increases the run-off and 
decreases the infiltration. The ponerine community at this location 
also included Plectroctena mandibularis and P. conjugata, Pachy- 
condyla sp. (soror-complex) and P. krugeri. 
Various nests were selected for intensive study, and every ant 
coming in or out of these was colour marked. Some ants were also 
collected inside the nests and marked. Spots of paint were applied to 
1-5 pre-selected dorsal positions and, with a choice of five colours 
(Humbrol enamel paint), a sufficient number of unique combina- 
tions was generated. The ants did not lose their marks with time 
because painted ants were observed for several months and unex- 
pected color codes were never recorded (the paint holds well to the 
pubescent cuticle). The activities of individual ants were monitored 
for varying numbers of days, with the help of a portable tape 
recorder. Many of the nests were excavated at the end of field visits. 
Field Observations 
Nest description 
Nests consisted of a number of underground chambers and galler- 
ies with no distinct spatial arrangement, and seldom extended deeper 
than 50 cm. Nest entrances were simple holes in the ground with 
little or no accumulation of soil around the hole. Active termite 
