Miami ant survey: where are the red imported fire ants?

Abstract In order to quantify the abundance of red imported fire ants ( Solenopsis invicta Buren) and other dominant ants (Hymenoptera: Formicidae) in the urban/suburban areas of Miami, we set out two hotdog baits at each of 49 sample sites along 80 km of roads with a sample area of about 400 km 2 . Red imported fire ants were found at only 8.2 % of sample sites and in 5.1 % of bait occurrences, ranking it in a tie for fourth or fifth place in the list of ants collected. The most common ants were Pheidole parva Mayr, Pheidole megacephala (Fabricius), and Pheidole subarmata Mayr, which were collected at 46.9 %, 18.4 %, and 12.2 % of sites, respectively. The majority of ants collected in this survey were exotic species, accounting for 93.6 % of species occurrences and 98 % of individuals. Dominant species of ants in the Miami area appear to have been dynamic over the last 50 years, several species have likely declined markedly (e.g. Solenopsis geminata (Fabricius) and S. invicta ) while two of the current dominant species, P. parva and P. subarmata, were unknown in Florida only 10 years ago.