Biological Control ofSolenopsisFire Ants byPseudacteonParasitoids: Theory and Practice

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.