D3172: Connections between invasive plants and diets of honeydew insects and fire ants in longleaf pine savannas

Fire ant (Solenopsis invicta) diets consist of many different foods, including sugary plant juices obtained from honeydew insects, facilitating rapid colony growth and possibly invasion of new sites. Longleaf pine savannas are areas of conservation concern in North Carolina. Our previous work indicated fire ant establishment, and invasive ryegrass (Lolium spp.) was a significant component of fire ant diets, despite ryegrass not appearing in these sites. We hypothesized that mutualistic relationships between fire ants and honeydew insects are allowing fire ants to access ryegrass. We are using ITS2 and rbcLa DNA barcodes to compare plant diets of fire ants and honeydew insects. Sanger sequencing based on ITS2 showed ryegrass in the diets of both honeydew insects and fire ants, while the rbcLa showed no ryegrass in the diets of either. We plan to use next-generation sequencing to compare the diets of honeydew insects and fire ants. Invasive plants could provide a novel food source for invasive fire ants, and the connection between the diets of honeydew insects and fire ants could suggest a potential pathway for the arrival of these invasive plants into the fire ant diet.