Social organization in a primitive ponerine ant: queenless reproduction, dominance hierarchy and functional polygyny inAmblyoponesp. (reclinatagroup) (Hymenoptera: Formicidae: Ponerinae)

Abstract

Social organization of colonies in the primitive ponerine ant Amblyopone sp. (reclinata group) was studied in Bogor, West Java, Indonesia. The colonies consisted of 97 workers on average, and there were no morphologically distinct queens; between one and 18 workers were inseminated and produced eggs, instead. Virgin workers developed their oocytes, but most of them degenerated before maturation. Experimental removal of mated laying workers (gamergates) from colonies resulted in oviposition by some virgin workers, suggesting that gamergates inhibit ovarian development of virgin workers. Degree of ovarian development of gamergates was not so different among gamergates within each colony; however, great variation was observed among colonies. This was correlated with number of virgin workers per gamergate. Among gamergates, aggressive antennation was frequently observed. The frequency of antennation increased with colony growth. A linear order was constructed by the antennation among gamergates, although there were many reversal interactions. Higher-ranked gamergates had 1–3 developed oocytes while three low-ranked gamergates had no developed oocytes. Since such sterile gamergates were rarely found in the field, low-ranked gamergates may be expelled from their colonies. Colonies of Amblyopone sp. were principally organized through physical and pheromonal interactions among individual workers. This paper provides the first demonstration of a dominance structure among gamergates and inhibitory effects of gamergates on reproductive activity of virgin workers in a functionally polygynous ant colony without queens.