Colony Founding Behavior of Some Desert Ants: Geographic Variation in Metrosis

The ants Pogonomyrmex catifornicus and Pheidole tucsonica display cooperative colony foundation with co-foundresses forming associations without respect to relatedness. Geographic variation in method of colony foundation [cooperative (pleometrosis) versus non-cooperative (haplometrosis)] occurs in P. californicus, Acromyrmex versicolor, Myrmecocystus mimicus and Messor pergandei. Such variation in colony founding behavior strongly suggests that comparative studies of the adaptive value of cooperative colony founding will be extremely rewarding.