Trophobiotic relationship between Solenopsis invicta and rhodesgrass mealybug (Hemiptera, Pseudococcidae) and the potential impact on fire ant management

The red imported fire ant (Solenopsis invicta) is commonly found in habitats dominated by grasses such as lawns, parks, athletic fields, golf courses, pastures, and roadside areas. These habitats often have limited plant diversity and have few nectar-producing species to provide carbohydrates needed to fuel the activities of fire ant workers such as resource discovery and domination, as well as, brood care, mound maintenance and defense. For this reason, rhodesgrass mealybug, Antonina graminis (Hemiptera: Pseudococcidae), appears to be an important resource providing ~70% of the carbohydrates utilized by fire ants in these habitats. To gain a better understanding of the nature of the relationship between fire ants and rhodesgrass mealybug and the importance of this carbohydrate resource, a field experiment was conducted to look at mealybug suppression. Plots were created in grassland habitats, half of the plots were treated with Endeavor®, an insecticide that targets sap feeding insects such as aphids, whiteflies, and mealybugs, and protein baits were used to measure fire ant activity in each plot. The results of this experiment showed that suppressing mealybug numbers resulted in a reduction of fire ant activity. This information led to feeding experiments to determine how available carbohydrate sources impact fire ant foraging on lipids and a bait product commonly used for fire ant management. The objective of this line of work is to determine if suppression of rhodesgrass mealybug, and the honeydew resource it provides, could be a beneficial tool for fire ant management.