232 
Psyche 
[September 
data, on this are available. Workers were not seen to feed the queen, 
so probably mandibular or other secretions from the head of the queen 
are not involved in this longevity factor. If mouth-to-mouth trophal- 
laxis occurred only at night, we would not have detected it. 
Workers of Neivmnyrmex carolinensis also became more attracted 
to chemicals deposited on paper by their queen after the ants had 
been kept in laboratory nests without queens for 16 days. When a 
queen is removed from an army ant colony in the field, the workers 
usually start “backtracking” or running along previous emigration 
and raid trails of the colony. Since more workers are attracted to 
the queen substance after they have been deprived of it for a number 
of days, this would be a mechanism for increasing the number of 
workers running along the backtracking columns. The ability of 
the workers to detect where a queen has stood suggests that they may 
be able to distinguish chemical trails along which a queen has run. 
Field observations in Panama with Eciton colonies from which queens 
have been removed showed that the workers primarily run along 
previous emigration trails but run, to a lesser extent on raid trails 
never used by queens. Backtracking and the ability of the workers 
to detect traces of a queen clearly are adaptations for colony survival. 
If a queen is lost by falling from an emigration route, these mech- 
anisms increase the chances that the workers will find their queen. 
Colonies which do not have queens either die or combine with an- 
other colony ( Rettenmeyer, 1963 : 309). A colony is unable to replace 
a queen that dies, except under the unusual condition where young 
queens are already developing within it. The ability to detect traces 
of a queen along trails of other colonies may provide the stimulus 
for colony fusion. 
Literature Cited 
Brian, M. V. 
1958. The evolution of queen control in the social Hymenoptera. Proc. 
10th Int. Congr. Entomol. 2: 497-502. 
Brian, M. V., and C. A. H. Carr. 
1960. The influence of the queen on brood rearing in ants of the genus 
Myrmica. J. Ins. Physiol. 5: 81-94. 
Brian, M. V., and J. Hibble. 
1963. 9-oxodec-trans-2-enoic acid and Myrmica queen extracts tested 
for influence on brood in Myrmica. J. Ins. Physiol. 9: 25-34. 
Carr, C. A. H. 
1962. Further studies on the influence of the queen in ants of the genus 
Myrmica. Insectes Sociaux 9: 197-211. 
