1986] 
Ward — Rhytidoponera me tallica 
9 
and continued to do so for six months, it seems likely that, under 
natural conditions, replacement of the queen by mated workers 
would be readily accomplished. Ward (1983) alluded to the possibil- 
ity that some worker-reproductive (Type B) colonies in the Rhyti- 
doponera impressa group are derived from orphaned queenright 
(Type A) colonies, and the present observations provide direct evi- 
dence that such a transition can occur in R. metallica. Moreover 
they suggest that reproductive activity on the part of the queen, 
rather than her mere presence, is necessary for the suppression of 
hostile takeover attempts by her daughters. 
The reverse process, production of colony-founding queens by 
worker-reproductive colonies, seems certain to have occurred. No 
mated dealate queen was found in the queen-producing colony from 
10 km SE of Kenilworth, and indeed no functional queenright colo- 
nies of R. metallica have been reported in the field, even though this 
species is one of the commonest Australian ants. 1 Haskins & 
Whelden (1965) reported the occasional production of female alates 
in worker-reproductive colonies of R. metallica which had been 
maintained in the laboratory for several years. These females failed 
to function as queens but this could have been due to the absence of 
favorable conditions for mating and dispersal. 
Queen production might be viewed as an infrequent, alternate 
dispersal strategy employed by worker-reproductive R. metallica 
colonies in response to environmental conditions which favor long- 
range dispersal over short-range movement (colony fission). The 
unusually large production of queens in Queensland in August-Sep- 
tember, 1983 occurred after a period of drought associated with the 
1982-83 El Nino. Alate queens appeared in one of Haskins’ labor- 
atory colonies after a shift in diet (C. P. Haskins, pers. comm.). The 
'Among the limited number of R. metallica queens in collections, the majority of 
specimens are alates; the dealate specimens which I have examined contain no infor- 
mation about their reproductive status. During a five year period of collecting ants in 
eastern Australia (1974-78; 1980) I encountered (and subsequently dissected) R. 
metallica queens only twice. One of these was a mated dealate female wandering on 
the ground by herself (colony-founding?) in open Eucalyptus woodland, 14 km E 
Grenfell, New South Wales (29. X. 1975, P. S. Ward #1406); the other was a single 
uninseminated (spermatheca empty, ovaries poorly developed) dealate female in a 
colony with 173 workers and brood, under a stone in dry sclerophyll forest, at 
Bathurst, N.S.W. (18. X. 1975, P. S. Ward #1374). 
