Queen recruitment in a multiple-queen population of the fire ant Solenopsis invicta

We assessed patterns of new queen recruitment in a polygene (multiple queens per nest) population of the fire ant Solenopsis invicta in its introduced range. Newly recruited queens were identified using four physiological markers, and genotypic data from nuclear and mitochondrial markers were used to estimate relatedness of new nest mate queens to each other and to the older nest mate queens. In total, 1.7% of the queens collected in late spring and early summer were deemed to be new recruits. The relatedness of these queens to each other and to the older queens within nests was not significantly different from zero, suggesting that newly recruited queens represent a random sample of potential reproductive queens in the population. Moreover, the number of new queens recruited within nests was not correlated with the number of older queens present and did not differ significantly from a Poisson distribution. Thus, queen recruitment in this population of S. invicta appears to occur at random with respect to the number of older queens present within nests.