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Volume 2014, Article ID 232057, 7 pages
Research Article

Evidence for the Absence of Worker Behavioral Subcastes in the Sociobiologically Primitive Australian Ant Nothomyrmecia macrops Clark (Hymenoptera: Formicidae: Myrmeciinae)

1ARC Center of Excellence in Vision Science, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
2CSIRO Ecosystem Sciences, Canberra, ACT 0200, Australia

Received 27 November 2013; Revised 2 March 2014; Accepted 20 May 2014; Published 18 June 2014

Academic Editor: Jacques Hubert Charles Delabie

Copyright © 2014 Robert W. Taylor. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Activity in three colonies of the nocturnally foraging Australian ant Nothomyrmecia macrops is investigated. Workers apprehended while foraging were marked, released, and later recaptured within nests following excavation. Every forager in each nest was encountered and marked. It was expected that unmarked, nonforaging, domestic-specialist workers would be discovered in the nests. This was unexpectedly not the case as all workers, apart from one or two in each colony, had been marked, and therefore had foraged at least once during the three-night experiment. The few unmarked individuals are considered to have been temporarily residential nest-entrance guards. Behavioral subcastes comprising “domestic” versus “foraging” workers were thus not indicated, evidencing absence of worker caste polyethism in Nothomyrmecia. The experiment predated emergence in the nests of adult workers from cocoon-enclosed pupae at a season when large feeding larvae of the current annual brood were still being provisioned by foragers. Because Nothomyrmecia is univoltine and emergence of current-brood adults had not yet occurred, all workers present were from preceding annual broods and defined as “postjuvenile.” A previous laboratory study separately evidenced absence of polyethism in Nothomyrmecia. Relevance of the apparent absence of food sharing in N. macrops is discussed.