STUDENT INSTRUCTIONS

      First work individually on this problem. Then work in pairs; one person will be the “solver”, the other the “recorder”. The “solver” explains how s/he figured out the figure, including description and interpretation of the data. The “solver” also poses questions they may have. The role of the recorder is to simply record what the solver says and to encourage them. The recorder does not attempt to help the solver interpret the figure. Your instructor will tell you how much time you have for the individual and paired work and how you will then report back to the whole class.

      Read through the information below, and then look at Figure 4. First, make sure that you understand the axes and the experimental design before you attempt to interpret the data. Observe the patterns in the data. Then discuss your interpretations together.

      The red fire ant was introduced to the U.S. from Brazil in the early 1940’s and since then it has spread throughout the south. It is a ferocious insect. The red fire ant kills baby chickens, ground-nesting birds, lizards, and snakes and it also attacks people. Control estimates in the southern states is about $1 billion per year.

      In this study Orr et al. tested the idea that a parasitoid fly from Brazil might reduce the red ant’s ability to attack other insects and animals. A parasitoid is like a parasite; it is a fly or wasp that kills its host by laying eggs in the larval stage of another insect and consuming the larva from inside. The design of their experiment is described in the figure legend.