Evolution of nesting strategies of ants: genetic evidence from different population types of Formica ants

Authors

  • P. PAMILO,

    1. Departments of Genetics and zoology, University of Helsinki, P. Rautatiekatu 13 SF-00100 Helsinki 10, Finland
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    • *Completed while visiting School of Zoology, University of NSW, Australia.

  • R. ROSENGREN

    1. Departments of Genetics and zoology, University of Helsinki, P. Rautatiekatu 13 SF-00100 Helsinki 10, Finland
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Abstract

Genetic population structure was studied in two types of populations in the ants Formica exsecta and F. pressilabris: populations consisting of single-nest colonies (monodomy) and populations consisting of multi-nest colonies (polydomy). These characteristics seem to be associated with the number of egg-laying females (gynes) in a nest, mating structure of the population, sex ratio and male size variation. The monodomous populations are characterized by single-gyne nests, the population sex ratio is either I:1 or female-biased, males are mainly large-sized, and there is slight inbreeding in the population. The polydomous populations have multi-gyne nests with gynes related to each other, sex ratio is strongly male-biased, most males are small-sized, and there is slight genetic microdifferentiation within the populations. Diploid males found in a polydomous F. pressilabris population suggest that the population is inbred and isolated. Habitat localization is presented as a plausible explanation for the evolution of the polygynous and polydomous population structure.

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