Interactions between the red imported fire ant, the citrus leafminer, and its parasitoid Ageniaspis citricola (Hymenoptera: Encyrtidae): Laboratory and field evaluations

Abstract

Interactions between the red imported fire ant [Solenopsis invicta (Hymenoptera: Formicidae)], the citrus leafminer [Phyllocnistis citrella (Lepidoptera: Gracillariidae)], and the citrus leafminer endoparasitoid Ageniaspis citricola (Hymenoptera: Encyrtidae) were investigated under laboratory and field conditions in Florida. Previous studies had shown that S. invicta would selectively prey on brown citrus aphids (Toxoptera citricida) parasitized by Lipolexis oregmae and Asian citrus psyllids (Diaphorina citri) parasitized by Tamarixia radiata, which led us to question whether S. invicta would selectively prey on citrus leafminer (CLM) larvae or eggs parasitized by A. citricola. In the laboratory trial, there was no significant difference between the type of CLM larvae preyed on. However, higher predation was observed on parasitized CLM larvae reared on potted plants in a citrus grove. A subsequent citrus grove test revealed slightly, although not significantly, lower levels of parasitism by A. citricola in trees to which ants had access because predation by ants was higher. However, predation by other predators in the trees to which ants had no access resulted in no significant differences in CLM densities in the two treatments. The field data provide, for the first time, the seasonal phenology of the CLM and its parasitoid A. citricola in the Indian River region of Florida in an unsprayed grapefruit block.

Keywords:

• Solenopsis invicta
• Phyllocnistis citrella
• Ageniaspis citricola
• intraguild predation
• parasitization

Acknowledgments

This work was supported in part by the Davies, Fischer and Eckes Endowment in Biological Control, the University of Florida Institute of Food and Agricultural Sciences and TSTAR. We thank Lucy Skelley, Reginald Wilcox, Anand Persad, and Patrick Duetting for assistance with the project. We also thank Dr Richard S. Patterson for providing the permethrin-embedded bands to exclude fire ants from the trees.