[C] Social insects

[C-46] アミメアリにおけるアリー効果

◯Kazuki Tsuji¹, Kentaro Nakayama¹ (1. Univ. of the Ryukyus)

In this study, we experimentally investigated Allee effect in the ant Pristomyrmex punctatus which has no morphological queen and workers parthenogenetically reproduce. Colonies consisting of 10, 40, 120, and 480 workers were established in the laboratory, and after 30 days of ad lib. feeding, the adult survival and the brood production efficiency were compared between colonies of different sizes. Statistically significant positive colony size dependence was observed in the worker survival, egg production efficiency, and larval production efficiency. To the best of our knowledge, this is the second instance of Allee effect in ants. The proximate mechanisms of this effect have been generally discussed as (1) reduced mating efficiency in sexually reproducing organisms and (2) reduced performance in group-living organisms. Clearly, the first hypothesis is not relevant to this parthenogenetic species.