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[Vol. 88 
approximately two months later do the first alate cocoons appear 
(December-January). Adult workers emerge from January until 
June, while alates eclose over a shorter time period (February- 
April). Most, or all, of the alates overwinter in the nest, and are 
released in the spring, possibly in several bursts, since some nests 
have been found with alates as late as November (and one nest with 
a single male in early December). 
Several points of interest emerge from the foregoing: 
(1) There is only one crop of adults produced each year, and 
alate production is restricted to a limited period of the total time 
that new offspring are produced. At any given time, the standing 
crop of new cocoons consists on average of no more than about 30% 
alates (Table 5). These facts may be relevant to a consideration of 
control of the sex ratio of investment. 
(2) No cocoons are overwintered, and there is a period of 6 
months (July-December) when no new individuals are added to the 
workforce. At first glance, this would seem detrimental to the 
increased foraging requirements during rapid larval growth in the 
spring and early summer. However, because of a time lag between 
worker eclosion and foraging (callow workers remain in the nest) it 
may in fact produce an effective increase in the foraging force when 
it is most needed. 
(3) In the absence of data on sex- and caste-specific growth 
rates, it is difficult to know whether alates arise from the overwin- 
tering larvae (hence, from eggs laid the previous season) or from 
eggs laid in the spring. However one piece of evidence suggests the 
latter: the discrepancy between the appearances of the first worker 
and first alate cocoons (two summer months) seems to be too great 
to be explained by assuming that equivalent-sized overwintering 
larvae require that extra period of time (and quantity of food) to 
develop into reproductives. Rather, it would seem more likely that 
the reproductives develop from spring-laid eggs or alternatively 
from smaller overwintering larvae. 
Not all nests of confusa and chalybaea contain alates in a given 
season, alate production being associated with larger colony sizes 
(Table 5). Nevertheless, there is considerable overlap in colony size 
between nests with and without alates, partly due to the fact that 
worker-reproductive colonies produce alates at a smaller size (and 
probably younger age) than queenright colonies (Ward, 1978). It 
seems likely that a variety of genetic, environmental, and develop- 
