Biological Control ofSolenopsisFire Ants byPseudacteonParasitoids: Theory and Practice

Lloyd W Morrison

doi:10.1155/2012/424817

Abstract

Pseudacteonparasitoids are potential biocontrol agents of invasiveSolenopsisfire ants.Pseudacteonspecies that parasitize the invasiveS. invictaBuren andS. richteriForel have been introduced to, and naturally dispersed across, the southeastern USA, although there is no evidence yet thatSolenopsishost ant populations have decreased. The ability of introducedPseudacteonspecies to regulateSolenopsispopulations will depend upon the relative importance of top-down effects in the recipient communities. In this paper, I examine the characteristics of thePseudacteon/Solenopsisparasitoid/host system and evaluate the extent to which research findings are consistent with top-down control. Laboratory and field experiments evaluatingSolenopsispopulation regulation have been equivocal, and overall the available evidence provides little support for strong top-down effects in this system. Competitive exclusion may occur among introducedPseudacteonspecies, and future efforts at biological control are likely to be more efficacious if they focus on other types of natural enemies.

Highlights

Many species of Pseudacteon (Diptera: Phoridae) are parasitoids of Solenopsis (Hymenoptera: Formicidae) fire ants
Much recent research has focused on the potential use of Pseudacteon parasitoids as classical biological control agents to regulate Solenopsis fire ant populations, S. invicta and S. richteri Forel in North America
It is estimated that P. tricuspis occurs in 65%, while P. curvatus may occur in as much as 90% of the invasive S. invicta/S. richteri range [3]

Summary

Introduction

Many species of Pseudacteon (Diptera: Phoridae) are parasitoids of Solenopsis (Hymenoptera: Formicidae) fire ants. Much recent research has focused on the potential use of Pseudacteon parasitoids as classical biological control agents to regulate Solenopsis fire ant populations, S. invicta and S. richteri Forel in North America. In addition to the direct effect of mortality, Pseudacteon phorids may have indirect effects on their Solenopsis hosts, affecting their behavior and potentially putting the host species at a relative disadvantage with competing ants [5]. There have been many studies conducted on various aspects of the Pseudacteon/Solenopsis parasitoid/host system, and the literature is in need of an objective, critical review. I do not attempt to review all the Pseudacteon/Solenopsis literature, but focus on the potential of introduced Pseudacteon parasitoids from South America to regulate population densities of host Solenopsis ants in their invasive range in North America, through both direct and indirect effects

The Species

Theory

The Evidence

Long-Term Experiments

Findings

Synthesis