1974] 
Moglich Holldobler — Nest Moving of Ants 
23i 
RRA-indices and by plotting the rank positions against the index 
values (Fig. 10). In the test colonies of both species the curve 
declines rather steeply indicating that the degree of specialization is 
high. We were able to prove the crucial role of this small group of 
specialists simply by removing them from the colony and observing 
the performance of the workers left behind. Although some regula- 
tive replacements by other workers appeared to be possible, the time 
needed for moving was considerably increased. When we also re- 
moved this second mover group, the colony was almost unable to 
achieve an organized nest emigration, even when their nest conditions 
became very unfavorable. Workers left the nest and dispersed, but 
no organized nest emigration took place. From this we conclude that 
a specialized group of nest movers exists and is important in leading a 
colony in a relatively short period of time from unfavorable to favor- 
able nest sites. 
According to the investigations by Otto (1958) and Kneitz 
(1964) we should expect that the moving specialists belong to the 
so called outside workers (Aussendiensttiere) with reduced ovaries. 
The dissection of all workers of the colonies showed that indeed all 
movers had reduced ovaries, whereas the ovaries of many of the ants 
being carried or led were relatively well developed. However, from 
our invstigations it became also clear that only a small portion of the 
“Aussendiensttiere” function as mover specialists. If they are re- 
moved experimentally, they can be replaced by other workers with 
reduced ovaries, whereas nestworkers (Innendiensttiere) with well 
developed ovaries cannot substitute for lost mover specialists. 
Summary 
Adult transport behavior is a common social activity in many ant 
species. It is employed most frequently as a recruitment technique 
during emigration from one nest site to another. As verified in this 
report, the behavior patterns vary among species and are correlated 
with phylogenetic groupings. 
The social organization of emigration, in particular the division 
of labor among workers during the process, was analyzed in two 
species, one of which recruits nestmates by carrying ( Formica san- 
guinea) and the other by tandem running ( Camponotus sericeus) . 
In both cases it was found that only a special group of workers 
organizes nest emigrations. All these moving specialists have com- 
pletely reduced ovaries whereas many of the carried or led ants have 
well developed ovaries. 
