26 
Psyche 
[Vol. 95 
apterous females may come out and mate again. They are generally 
inseminated but dissections have shown that there are exceptions. It 
is well known in ants that virgin queens lose their wings after some 
delay if they are not inseminated. During this period we find polyg- 
ynous nests in the field. Such nests are rare and polygyny lasts only 
a few days. Supernumerary queens are rejected by workers if bud- 
ding does not occur rapidly. Ostracized queens leave the nest and 
die. We dissected 2 of these rejected queens: they were not insemi- 
nated. Dead queens are also expelled from the nest. 
Mating in the laboratory 
We obtained matings between sexuals of different colonies in the 
laboratory. The length of mating was variable, from 40 sec. to more 
than 16 minutes (mean = 333s; n = 9). This may have been related to 
the low temperature of the laboratory (25° C). These observations 
are comparable to others in Formica where the mean time is 3,1 min 
(range 0.5-7. 5 min) (Rosengren et al. 1986). The presence of a full 
spermatheca indicated a successful copulation. In all the observed 
cases the females reentered their artificial nest. During this period 
the societies are polygynous with the old queen and newly insemi- 
nated queens. In the laboratory some colonies kept several queens 
for a long time (until wintering). Later they again became monogy- 
nous. The mechanism for the elimination of supernumerary queens 
is unknown: aggression between queens or aggression of queens by 
workers? Is the surviving queen the old queen? In our colonies the 
surviving queen was not the old one (as indicated by individual 
marking), but additional observations are needed. 
4. Foundation of new colonies 
Budding was observed twice in the field in 1985, after the period 
of mating. Workers transported larvae, cocoons and other workers 
to a new nest. We may suppose that explorers had previously 
localized unoccupied holes which could be used as a new nest site. 
Transporting workers made many journeys between the two nests. 
Moving was directed towards 3 nest sites in the 1st case (Fig. 2) and 
4 nest sites in the second case. The mean distance to the new nests 
was 6.5 m (range 3.2-1 1.3 m). 
Traffic lasted for two days. In Fig. 2 shows that nest 2 was aban- 
doned, and then occupied later by a colony which moved totally 
from nest 1. Nest 5 was abandoned after 3 weeks and the colony 
divided in two sister colonies, at least one of which had a new queen. 
