FIGURE SET 4

Figure 4. Number of fire ants (Solenopsis invicta) surging from an ant colony. There were 10 baits each consisting of a 0.5 cubic centimeter piece of cow heart muscle staked to the ground with a pin. The bait was placed 10 centimeters away from each colony. All ants standing on or feeding on the bait were counted every hour until fire ants dominated all baits. The black circles indicate presence of the added parasitoid fly, called a phorid. Time of day is military time (1300 is 1 PM, 1400 is 2 PM, etc.). Phorids departed naturally at dusk and on day 2 for colony 1 phorids were experimentally removed before dusk. Filled bars are S. invicta. Open bars are several other ant genera. Bars further to the left at each hour are baits closer to the mound. Solid circles are maximum number of phorids attacking S. invicta during the 30 minute period before the ant count. Fire ants were never displaced from baits by other ants in the absence of the phorid during a 6 week observation period before the experiments. No other ant species visiting the baits were attacked by the phorid (from Orr, M. R., S. H. Selke, W. W. Benson, and L. E. Gilbert. 1995. Flies suppress fire ants. Nature 373: 292-293).

For help, see the essay "Helping Your Students to Interpret Figures and Tables."