Comparison of brain volumes between single and multiple foundresses in the paper wasp Polistes dominulus

Queens of the paper wasp Polistes dominulus have the option to found nests in spring alone or together with other queens. In the latter case a dominance hierarchy is established among the cofoundresses with the dominant wasp getting the major share of the reproductive output of the nest. The different reproductive strategies of an individual wasp will necessitate different behaviors. We measured the volumes of brain structures as a potential indicator of differential use and elaboration of a number of brain structures. We found a significant increase in the volume of the antennal lobe in members of multiple foundress associations in comparison to single foundresses. The volume of the collar, a substructure of the calyx of the mushroom body, was also significantly larger, especially in the dominant queen of a foundress association. No significant differences between dominant or subordinate wasps in regard to volume of the measured brain substructures were found.