Stability of polygyne and monogyne fire ant populations (Hymenoptera: Formicidae: Solenopsis invicta) in the United States.

Over the past decade, polygyne red imported fire ants (Solenopsis invicta Buren) have been found at more and more sites across the southeastern United States. The objective of my study was to determine if polygyne (multiple-queen) populations are expanding and at what rate this might be occurring. More than 200 sites were inspected for polygyny in Florida and several other southeastern states. These sites were reinspected 1-3 yr later. Results showed that polygyne populations were not expanding rapidly in the areas studied (i.e., > 4-6% per yr); however, more data will be needed to determine if polygyne populations are expanding slowly (i.e., 1-2% per yr). Overall, polygyne and monogyne sites were about 95% stable from year to year; in other words, they did not commonly switch back and forth from one form to the other. As expected, average mound densities in the Florida survey (62 sites) remained relatively constant from 1990 to 1992.