A second phorid fly species, Pseudacteon~ddd~~~ddd~~~dd curvatus Borgmeier from Formosa,

Argentina, was released in Florida to control populations of red imported fire ants,

Solenopsis invicta Buren (Vazquez et al. 2004b). Pseudacteon curvatus is a small

decapitating fly that normally parasitizes small red imported fire ant workers. Quarantine-

based host specificity testing predicted that this Formosa biotype was highly host-specific

to S. invicta and that nontarget effects to the native fire ants, Solenopsis geminata

(Fabricius) and Solenopsis xyloni McCook would be minimal to non-existent (Vazquez et

al. 2004a). The obj ective of this paper is to document the host specificity of established

field populations of the Formosa biotype of P. curvatus.

 Materials and Methods

 The P. curvatus flies were collected attacking S. invicta fire ants 35 km NW of

Formosa, Argentina by Sanford D. Porter and Juan A. Briano (October 2001).

Pseudacteon curvatus was first successfully released and established in Florida at

Whitehurst Farm, 15 mi SW of Gainesville, FL in the spring of 2003 (Vazquez et al.

2004b). Field observations of host specificity were made in October 2003 between 1300

and 1530 EST, when the temperatures were > 24oC. I tested the attraction of established

P. curvatus flies to 15 species of non-Solenopsis ants: Aphaenoga~ster miamniana Wheeler

(0.8-0.9 mm head width, 0.2 g of workers used), Aphaenoga~ster c.f. carolinensis Wheeler

(0.7 mm, 0.7 g), Camponotus floridd~~dd~~ddanus (Buckley)(2.2 mm, 4 g), Camponotus impressus

(Roger)(0.7-0.8 mm, 0.6 g), Crematogaster minutissima Mayr (0.6 mm, 2 g),

Crematoga;ster pilosa Emery (0.7-0.9 mm, 2 g), Cyphomyrmex rimosus (Spinola)(0.6

mm, 0.2 g), Dorymyrmex bureni (Trager)(0.7-0.9 mm, 0.3 g), Forelius pruinosus

(Roger)(0.5 mm, 0.3 g), Linepithema humile Mayr (0.6 mm, 2 g), Odontomachus

brunneus (Patton)(1.8 mm, 0.4 g), Pheidole dentat Mayr (0.6 mm minors, 1.2 mm