Passage V

When attacked by predators, tadpoles secrete Protein F into their surroundings. A scientist conducted 2 experiments with Protein F: one to examine how the activity of tadpoles changes immediately after a period of exposure to Protein F and the other to examine how depriving tadpoles of food affects their activity during a subsequent period of exposure to Protein F.

Experiment 1

One hundred tadpoles were equally divided into 4 groups (Groups 1-4). The groups were separately placed into equal volumes of water having the Protein F concentrations shown in Table 1.

After 2 hr, the groups were separately placed into equal volumes of pure water. The tadpole activity of each group was then monitored at regular intervals over the next 90 min. (The tadpole activity of a group was the number of tadpoles that were swimming during a 5 sec observation period. ) The results are shown in Figure 1.

Figure 1 adapted from Michaol E. Fraker, "The Dynamics of Predation Risk Assessment: Responses of Anuran Larvae to Chemical Cues of Predators." @2008 by British Ecological Society.

Experiment 2

Two hundred tadpoles were equally divided into 4 groups (Groups 5-8), and the groups were separately placed into equal volumes of pure water. Each group was deprived of food for a specific length of time: Group 5 for 24 hr, Group 6 for I hr, Group 7 for 12 hr, and Group 8 for 24 hr. At the end of their respective deprivation periods, the groups were separately placed into equal volumes of water having the Protein F concentrations shown in Table 2.

The tadpole activity of each group was then monitored at regular intervals over the next 150 min (see Figure 2).

Figure 2 adapted trom Michael E. Fraker, "Risk Assessment and Anti-Predator Behavior of Wood Frog (Rana sylvatica) Tadpoles: A Comparison with Green Frog (Rana clamitans) Tadpoles." @2010 by Society for the Study of Amphibians and Reptiles.