from January to May of 2004. Fly abundances in 2004 have ranged from 27-55 flies per 5

mounds (median = 40).

 Flies were also successful at establishing at both Morrill and Mickle sites. In April

and May 2004, 5-10 flies were found at the Morrill Pasture and 15-25 flies found at the

Mickle site (Table 3-1). Earlier attempts to monitor P. curvatus presence at these two

sites failed to yield positive results from observations made twice weekly for several

months (June-October 2003, Table 3-1). In the summer of 2003, I found large numbers of

P. tricuspis at the Mickle site (80-110 flies) but no P. tricuspis flies were found at the

Morrill site in spite of the fact that they had been very abundant in previous years. In

April and May 2004, I found a total of 75 P. curvatus flies at the Mickle site compared to

12 P. tricuspis; at the Morrill site it was 15 to 0 respectively.

 In August 2003, flies had dispersed about 200 yd from the original release site at

Whitehurst Ranch. In April-May 2004, the flies had expanded 1.6 km both North and

South and about 0.8 km in a westward direction (May 2004). To the East of the site is a

heavily wooded area that is not accessible to motor vehicles. I found a total of 15 flies on

these outer boundaries as well as the presence of a few P. tricuspis flies. Dispersal rates

for the Morrill and Mickle pastures will be conducted in late summer 2004.

 Discussion

 This study documents the first successful release and establishment of the

decapitating fly P. curvatus on red imported fire ants in the United States. A post release

specificity test in the fall of 2003 (Vazquez and Porter 2004) with non-Solenopsis ants

and the native fire ant, Solenopsis geminate (Fabricius), confirmed laboratory predictions

(Vazquez et al. 2004a) that this biotype from Formosa would be specific to red imported

fire ants. First generation flies were found within 5 weeks after release at the Whitehurst