The fire ant decapitating fly, Pseudacteon bifidus (Diptera: Phoridae): host specificity and attraction to potential food items

Headnote

Abstract

The tropical fire ant, Solenopsis geminata (F.) (Hymenoptera: Formicidae), is an invasive pest throughout most of the tropics, especially on islands in the Pacific. Natural enemies such as the fire ant decapitating fly, Pseudacteon bifidus Brown and Morrison (Diptera: Phoridae), offer the potential for use as self-sustaining biological control agents provided they are host specific and do not cause other unintended problems. This paper provides details of sequential field and laboratory choice tests with host and non-host ants, as well as tests with a variety of potential food items to which adult flies may be attracted. Results of these tests showed that P bifidus flies are highly host specific to tropical fire ants and that they are not attracted to ants in other genera. Even other species of fire ants are unlikely to be parasitized by this fly in the field. Furthermore, tests with a variety of food items demonstrated that P bifidus is not likely to be a nuisance to humans because it is not attracted to carrion, feces, fruits, or various kinds of human food items. In short, P bifidus would not likely cause unintended problems if it were used as a self-sustaining biological control agent of invasive tropical fire ants.

Key Words: Solenopsis geminata; host range; diet preferences; biological control

Resumen

La hormiga de fuego tropical, Solenopsis geminata (F.) (Hymenoptera: Formicidae), es una plaga invasora en la mayor parte de los trópicos, especialmente en las islas del Pacífico. Enemigos naturales como la mosca decapitadora de la hormiga brava, Pseudacteon bifidus Brown y Morrison (Diptera: Phoridae), ofrecen el potencial de usarlos como agentes autosostenibles de control biológico siempre que sean específicos al hospedero y no cause otros problemas no deseados. Este artículo provee detalles de pruebas secuenciales de elección en el campo y laboratorio con hormigas hospederas y no hospederas, así como, pruebas con una variedad de posibles alimentos que podrían usarse para alimentar las mosquitas adultas. Resultados de estas pruebas mostraron que las mosquitas P bifidus son altamente específicas para las hormigas de fuego tropicales y que no son atraídas por hormigas de otros géneros. Incluso, es poco probable que hormigas de fuego de otras especies sean parasitadas por esta mosca en el campo. Además, las pruebas con una variedad...