Specificity of the Red Imported Fire Ant Phagostimulant Response to Carbohydrates
The red imported fire ant, Solenopsis invicta Buren, is considered an oil-loving feeder, however, carbohydrates are essential ingredients in the diet of the fire ant also. Comprehensive screening of mono-, di-, and tri-saccharides demonstrated that glucose, fructose, fucose, sucrose, maltose, turanose and raffinose were significant phagostimulants for fire ant workers. It was also found that while D-glucose and L-fucose, the naturally occurring isomers, were active, the opposite diastereomers were not. Any structural modification of the glucose molecule resulted in loss of activity. None of the sugar alcohols evaluated were active. The fire ant is an agricultural pest and the many reports of fire ant damage to food crops may be linked to their need for dietary carbohydrates. A knowledge of carbohydrate phagostimulants may help to understand specificity of fire ant /plant interactions.
Impact of the Red Imported Fire Ant, Solenopsis invicta (Hymenoptera: Formicidae), on the Growth and Yield of Soybeans
The yield of soybeans, Glycine max (L.) Merr., from experimental plots infested with the red imported fire ant, Solenopsis invicta Buren, was 400 to 575 kg less per ha than that from comparable noninfested plots. The loss was attributable primarily to destruction of germinating seeds and seedlings, as evidenced by significant reductions in plants per meter of row in the infested plots. Evidence obtained from 32p radioisotope studies showed that the ants also fed on growing plants, probably on their roots. Growth, as measured by plant height, was reduced in the ant-infested plots, a factor that could be associated with root-feeding activity. It is suggested that the impact of red imported fire ants on germinating soybean seeds is associated with planting dates (May and June) which coincide with a period of food stress associated with intense brood-rearing activity by the ants.
The control of food flow in a society of the ant Myrmica rubra L
Abstract The control of prey, thin syrup and water flow, through a society of Myrmica was studied. Larval intake increases if they are deprived of prey, but not if they are deprived of water or sugar. Deprivation causes them to take prey juices from workers and they get more if the workers themselves have also been deprived; this is because such workers over-collect and readily pass on their surplus. Even well-fed larvae will take prey juices from these surfeited workers; they will also take sugary fluids but not water. The head of a larva elicits some food collection by workers even if it is immobile, but the real cause of food flow towards larvae is their ability to absorb and assimilate the prey juices which they can obtain from workers. Starved nurse workers can obtain prey and water from foragers but a reverse flow does not occur; only thin syrup is exchanged freely between workers.