1967] 
Watkins & Rettenmeyer — Army Ants 
229 
oratory nests. Colony samples with a queen and brood often can be 
kept for several months, but most of the brood is eaten; usually no 
further eggs are laid. We have seen no sign of eggs laid by workers 
in nests without queens. We had one queen of Neivamyrmex 
nigrescens become physogastric in the laboratory and lay eggs. Some 
of these developed into adult workers, but the size of the brood was 
much smaller than broods found in the field. Since workers with 
queens seemed to live longer than those without queens, we did the 
following experiment. 
LONGEVITY OF WORKERS HOUSED WITH AND WITHOUT QUEENS 
One thousand workers from the same colony of Neivamyrmex 
carolinensis (Emery) were placed in each of eight laboratory nests. 
One queen from the same colony having multiple functional queens 
was also placed in each of four of These nests. Ants in each nest 
were fed daily the same number of live German cockroaches (Blatella 
germanica) and ant larvae ( Crematogcister sp.). No brood appeared 
in any nest. The numbers of live workers were counted after 30 
days (Table 1). The queens remained alive and active throughout 
the test. The mean survival with a queen was 78% higher than the 
survival without a queen. 
Table 1. 
Effects of queens on the 
longevity of workers of N. 
carolinensis. 
No. live workers after 30 days 
Replica 
Queen and 
Workers 
Probability 
workers 
only 
1 
466 
27 
< 0.005 
2 
629 
462 
< 0.005 
3 
627 
296 
< 0.005 
4 
623 
531 
< 0.010 
Means 
586 
329 
< 0.005 
In a similar experiment, 2,000 workers of N eivamyrmex carolinen- 
sis were placed in each of four laboratory nests, and three queens 
from the same colony were put in each of two nests. At the end of 
30 days, all workers in nests without queens were dead, but more than 
50% of the workers and two of the three queens in the other nests 
were alive. 
ATTRACTION OF WORKERS HOUSED WITH AND WITHOUT 
QUEENS TO QUEEN SECRETIONS 
After army ant queens have stood on a paper surface, workers 
from their colony will be attracted to the paper (Schneirla, 1953; 
Watkins and Cole, 1966). Watkins and Cole showed that workers 
