REPRODUCTIVE COOPERATION BETWEEN QUEENS AND THEIR MATED WORKERS - THECOMPLEX LIFE-HISTORY OF AN ANT WITH A VALUABLE NEST

The life history of Harpegnathos saltator is exceptional among ants be cause both queens and workers reproduce sexually. Recently mated queen s start new colonies alone, but later some of the offspring workers al so become inseminated and take over the egg-laying role. This alternat ion seems associated with the existence of very complex underground ne sts, which are designed to survive floods. Longevity of ponerine queen s is low (a consequence of limited caste dimorphism in this ''primitiv e'' subfamily), and upon the death of an H. saltator foundress, the ne st represents a substantial investment. The queen's progeny should thu s be strongly selected to retain the valuable nests. Unlike the flying queens, the workers copulate with males from their own colonies, and, thus, their offspring are expected to be highly related to the foundr ess. Colony fission appears not to occur because a daughter fragment w ould lack an adequate nest for protection. Thus, the annual production of queens in colonies with reproductive workers remains essential for the establishment of new colonies. This contrasts with various other ponerine species in which the queens no longer exist.