EFFECTS OF ARMY ANT QUEENS ON LONGEVITY 
OF THEIR WORKERS (FORMICIDAE: DORYLINAE) 1 
By Julian F. Watkins II 2 and Carl W. Rettenmeyer 3 
Many species of ants can be kept readily for months or years in 
laboratory nests in which survival and colony growth are probably 
greater than that in the ants’ natural environment. If worker ants 
are kept without their queen (s), survival of adult ants sometimes does 
not appear to be greatly decreased. For example, we have kept 
Camponotus pennsylvanicus (DeGeer), Pogonomyrmex occidentalis 
(Cresson), and P. barbatus (F. Smith) in laboratory nests without 
queens for io to 20 months. Although some of the workers often 
lay eggs, the colony gradually dies out. Skaife (1961: 141) deter- 
mined the longevity of Iridomyrmex humilis Mayr by keeping about 
3,500 workers in a nest without brood or queen. Half the workers 
died in ten months, and all were dead in 15 months. However, if 
the results of our experiments are applicable to other ants, isolating 
ants from their queens will greatly reduce survival. 
There is evidence that queen ants influence the development or 
survival of a brood, but we 'have been unable to find data regarding 
the survival of adult workers. Brian and Hibble (1963) reported 
that Myrmica queen heads crushed in ethanol suppressed, and mandib- 
ular glands in paraffin oil stimulated, the growth of brood. Brian 
(1957) and Brian and Carr (i960) found that queens of Myrmica 
scabrinodis and M. rubra increased early larval growth, caused a 
smaller pupal size, improved survival of the brood, and diminished 
the production of gynes. Carr (1962) reported that dead queens 
of Myrmica also produced a measurable effect on the growth of 
larvae. 
Army ants are among the most difficult ants to keep alive in lab- 
^Contribution No. 936, Department of Entomology, Kansas Agricultural 
Experiment Station, Kansas State University, Manhattan, 66502. Supported 
by National Science Foundation Grant GB-52 and Kansas Agricultural 
Experiment Station Project 603. Manuscript received by the editor Sept. 25, 
1967 . 
2 Former National Defense Education Act Fellow, Kansas State Univer- 
sity; now Assistant Professor, Department of Biology, Baylor University, 
Waco, Texas 76703. 
3 Associate Professor, Department of Entomology, Kansas State Univer- 
sity, Manhattan. 
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