Food preferences of Solenopsis geminata workers in anthills located at the premises of Eastern University, Sri Lanka

Abstract

The tropical fire ant, Solenopsis geminata (Fabricius, 1804) causes ecological disruptions and economic damage in tropical regions of the world. Effective control strategies for tropical fire ants rely on understanding their ecology. The current investigation focused on recording the preferred food type among six food types, with an intention of developing an effective ant bait formulation, which is to be based on the preferred food types later. Three localities, each 100 m apart, were selected at the premises of the Eastern University of Sri Lanka, and two active S. geminata anthills were identified by recognizing worker ants at each site. A 1.1 g weight of selected food items, peanuts, crushed sugar, honey, soybean oil, corn grit, and corn flour, were placed 15 cm away from each anthill at approximately a 60º angle and protected from other animals. The number of ants attracted to each sample of food was counted from 8.00–10.00 a.m. and, remaining food was weighed and deducted from the original weight to determine the amount of the food consumed by the ants. This procedure was done over 12 consecutive sunny days with air temperatures ranging between 28 °C and 37 °C. ANOVA test followed by Tukey's HSD was applied to determine the significant differences between the mean weight of each food type consumed by the ants. Worker ants formed trails to gather soya bean oil and corn grit on all occasions, while only 50–65 of ants were observed around the other types of food. The results showed that S. geminata strongly preferred soya bean oil and corn grit over other commercially available food types (p = 0.01; Tukey's HSD), suggesting their potential use in effective bait formulations. Future research should explore the optimization of bait formulations incorporating soya bean oil and corn grit.