COLONY STRUCTURE AND REPRODUCTION IN THE ANT, LEPTOTHORAX-ACERVORUM

We analyzed the sociogenetic organization of the ant (Leptothorax acer vorum) from Nurnberger Reichswald in Southern Germany. According to re latedness estimates from allozyme analyses, virgin female sexuals prod uced in polygynous colonies were on average full sisters, whereas work ers in a pooled sample of polygynous colonies were significantly less closely related. Rather than attributing this to reproductive hierarch ies among nest mate queens, we show how this phenomenon could result f rom seasonal fluctuations of colony composition and a decline of the p roduction of female sexuals in polygynous colonies. We suggest that by queen adoption and emigration or budding, colonies easily switch from monogyny to polygyny and vice versa. Due to the long developmental ti me of sexual larvae, colonies that have become polygynous only recentl y will still produce the female sexual progeny of a single queen. In o lder polygynous nests, fewer and fewer female sexuals are produced, bu t colonies may fragment into monogynous buds in which the production o f female sexuals may begin again. Relatedness estimates, dissection re sults, and field observations support this suggestion. This pattern of cyclical monogyny and polygyny keeps nest mate relatedness high and p robably facilitates colony founding in boreal habitats. Preliminary da ta suggest that the pattern of the production of sexuals in colonies o f L. acervorum fits the expectations of sex allocation theory.