Liquid foods, particularly carbohydrates, are important food sources for the red imported fire ant, Solenopsis invicta Buren. Mature colonies of the red imported fire ant are large, consisting of several hundred thousand individuals, and use a mass recruitment system to retrieve food items for the colony. Fire ants are known to travel relatively great distances (30-40 m) to harvest honeydew off Homoptera in trees. Foraging theory predicts that as the cost of obtaining a resource increases, ant workers should select recruitment behaviors that optimize colony fitness. Further, the practical question of how far fire ants will recruit across pesticide treated areas is relevant to control strategies.
The purpose of this study was to determine, under controlled laboratory conditions and at the individual and collective level, the transport strategies of fire ants at different distances. Four mature monogyne colonies were placed in arenas, each with up to 32 m of forage distance available. Feeding stations were established at 8, 16, and 32 m from the colonies. Each treatment consisted of only sucrose solution (25% w/v), and only at one distance. Series of individuals were removed from each of four locations at each of the distances: leaving the colony, arriving at the food, leaving the food and arriving at the colony. Body mass and carbohydrate load was determined for each individual. Results show that fire ants have different strategies for transporting food at different distances. In the shorter distances individuals went all the way to the food source to load, at the longer distance a bucket brigade system developed where ants transferred food at way stations alongside the recruitment trail. Possible reasons for these different recruitment strategies, and the various costs to the colony in distance foraging, are discussed.
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA