Queen lifespan and colony longevity in the ant Harpegnathos saltator


*Jürgen Liebig, Lehrstuhl für Verhaltensphysiologie und Soziobiologie (Zoologie II), Biozentrum, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany. E-mail: jliebig@biozentrum.uni-wuerzburg.de


Abstract.  1. The longevity of field colonies was investigated in the ponerine ant Harpegnathos saltator (Jerdon) in which either reproductive workers (gamergates) or a single queen reproduce.

2. Data from 3 years were used to calculate the ratio between queen-right (n = 50) and gamergate (n = 12) colonies that can be used to derive the colony mortality of gamergate colonies. Using the survival rates of queens in the laboratory, extrinsic and intrinsic mortality rates of queen-right colonies were calculated.

3. No significant differences in the sizes of queen-right and gamergate colonies above 14 workers was found, suggesting that mortality of established colonies is not size related.

4. The mortality of gamergate colonies is 4.17 times higher than the intrinsic mortality of queen-right colonies.

5. In the laboratory, mean survival time of queens in colonies of more than 14 workers was 1.79 years.

6. Estimated mean survival time of queen-right and gamergate colonies in the field varies between 0.78 and 0.43 years respectively, when no costs of conflict during the replacement of queens occur; however, when the latter costs increase colony mortality to a level similar to extrinsic mortality, the calculated longevity of queen-right colonies would increase to 1.02 years.