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[Vol. 92 
dealation of offspring. However, colonies which were polygynous at 
this time (n = 27) did not bud more frequently than other colonies 
(x 2 = 2.65, df = 1, P> 0.05); and, within this group, colonies which 
budded were significantly larger than those which failed to do so 
(t = 2.365, df = 25, PC0.05). 
Discussion 
The results of this study provide further empirical evidence for the 
existence of polydomy in L. curvispinosus colonies (see Sturtevant 
1927). Moreover, these results demonstrate that at least some of the 
factors which are capable of inducing polydomy in these ants 
remain active under relatively simple laboratory conditions. The 
observed relationship between colony size and the occurrence of 
polydomy suggests that space limitations within nests could be a 
factor promoting polydomy. Nesting sites such as hollow nuts and 
twigs might well impose this kind of limitation on colonies in 
nature. However, other factors associated with colony size, age or 
maturity could also be involved. Furthermore, it is likely that var- 
ious factors can effectively induce polydomy in species in which 
colonies are capable of existing in this condition. In nature, colonies 
might become polydomous in response to the distribution of food 
around their nests or to exploit different humidities or temperatures 
in different nests, perhaps selectively distributing their brood or 
reproductives in this manner. The present experiment, with its uni- 
form plastic nests and simplistic foraging environment, provided 
little opportunity for these kinds of factors to operate. 
Among leptothoracine ants, a polydomous colony structure 
could have various important ramifications, depending at least in 
part on the relative degree of contact between nests within colonies. 
This colony structure might affect the way in which reproductive 
rights are apportioned among different queens and workers (see 
Wilson 1974a, b; Cole 1981; Franks and Scovell 1983), and it might 
influence the relative susceptibility of colonies to social parasites 
(see Alloway et al. 1982; Del Rio Pesado and Alloway 1983). 
Indeed, the combination of polygyny and polydomy is thought to 
have been an important factor in the evolution of various forms of 
social parasitism (Buschinger 1970; Alloway 1980). 
The existence of polydomy in these ants may explain a peculiar 
element of their nest emigration behaviour. Moglich (1978) investi- 
