SEX ALLOCATION AND COLONY MAINTENANCE IN MONOGYNE AND POLYGYNE COLONIES OF FORMICA-TRUNCORUM (HYMENOPTERA, FORMICIDAE) - THE IMPACT OF KINSHIP AND MATING STRUCTURE

The aim of this article is to discriminate between genetic (worker-que en conflict) and ecological (mating structure, colony productivity) de terminants of resource allocation in ants. Both the allocation to grow th Versus reproduction (reproductive allocation) and the allocation to males versus females (sex allocation) were analyzed as a function of colony kin structure, colony productivity, and mating structure in mon ogyne and polygyne populations of the ant species Formica truncorum. C olonies headed by single queens (monogyne colonies) were smaller and p roduced more sexuals per adult worker than those with multiple queens (polygyne colonies). Monogyne colonies with a high total production re lative to colony size invested excess resources in reproduction, where as the reproductive allocation did not change with increased productiv ity in polygyne colonies. The results suggest that workers control rep roductive allocation. The population-level sex ratio was female biased in the monogyne population and male biased in the polygyne population . The colony-level variation in sex allocation in the monogyne colonie s was best explained by variation in relatedness asymmetry (the relati ve relatedness of workers to males vs. females) among colonies, togeth er with colony size and the percentage of sexuals in the brood (r(2) = 0.77). In polygyne colonies male bias increased with increasing produ ction of sexuals, which suggests that local resource competition was t he main determinant of colony-level sex-allocation variation in these colonies.