1981] 
Levings & Traniello — Territoriality in Ants 
273 
results from such theft and how much is independently gathered. 
Examples include Leptothorax acervorum and various Cardio- 
condyla species (Brian 1955; Wilson 1959a, 1971). These species 
usually recruit few other workers to the food item; many of these 
species recruit only one other nestmate using tandem running 
(Wilson 1959a). No spacing information is available for these 
species. 
The fourth set of species include the legionary ants (true group 
foragers) and most of the specialists on extremely difficult prey 
(Groups IV and V, Oster and Wilson 1978). These species defend 
only their nest sites (which may move often) and forage in various 
sized groups. The most spectacular examples of this type of foraging 
are the army ants (Schneirla 1971). Specialists on difficult prey 
occur in several genera (examples, Pachycondyla ( =Termitopone ), 
Leptogenys, Gnamptogenys)\ specialized retrieval methods may 
involve extensive cooperative foraging (Wilson 1971). Little nest 
spacing information is recorded about these groups. Army ants of 
several genera have been observed to avoid each other when they 
meet in the field, but no similar information is available for related 
groups (Schneirla 1971). Other legionary groups are relatively rare 
on BCI and, in 4 years of field work, no interactions were observed 
(Levings, personal observation). 
In general, information on spacing patterns of ants which defend 
only their nests is extremely difficult to gather, since the investigator 
must usually depend upon luck to locate colonies and will never be 
certain that all colonies in an area have been found. Because 
information on foraging ranges for most species is unavailable, we 
are unable to test those aspects of our hypotheses. Many species 
which are now assumed to defend only their nest sites may well be 
found to defend either resources or a foraging territory. 
2. Resource defense 
a. short term 
The defense of unpredictable resources occurs on varying time 
scales. Resources which persist for very short periods (i.e., minutes 
for most dead insects) are defended by many generalist or scavenging 
ants during the recruitment/ retrieval process (Groups II & III, in 
part, Oster and Wilson 1978). Spatial overdispersion in densely 
populated areas has been shown in one complex tropical com- 
munity (Levings and Franks 1982). It is probably typical of many 
