ANT PREFERENCES. Introduction. Time Needed. What You Need

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1 ANT PREFERENCES Introduction Ants, shown in Figure 1, are described as social insects because they live in colonies. In most species, all members of a colony of ants are descendants of the ant queen. Within the colony, worker ants have jobs such as collecting food, tending to the queen, and taking care of developing eggs. Workers pick up solid food with strong lower jaws, or maxillae, and they take in liquid nourishment with their tongues. Ants eat a variety of foods, but prefer some food types over others. In this experiment, you will find out which flavor ants prefer: sweet, sour, bitter, or salty. Time Needed 30 minutes on day 1 55 minutes on day 2 What You Need 200 ants (approximately) 1 slice of white bread small aquarium (or large, clear plastic or glass container) with lid soil (about 4 cups) leaf litter or shredded paper (about 2 cups) water in a spray bottle 5 baby food jars 5 eye droppers 1/2 teaspoon (tsp) salt 1/2 tsp sugar

2 ANT PREFERENCES 2 1/4 tsp citric acid 1/4 tsp caffeine spoon or stirring rod knife 10 squares of aluminum foil (4 centimeters [cm] 4 cm) ruler labels permanent labeling pen access to water science notebook Safety Precautions Handle ants with care, touching them as little as possible. After working with ants, wash your hands with soap and water. Take care when working with a knife. Please review and follow the safety guidelines. What You Do: Day 1 1. The purpose of this experiment is to find out whether ants prefer one flavor over another. In your science notebook, predict which flavor you think the ants will prefer: sweet, sour, bitter, or salty. 2. Prepare a habitat for the ants. To do so: a. Spread the soil on the bottom of the aquarium. b. Distribute the leaf litter or shredded paper on top of the soil. c. Lightly spray the soil and leaf litter with water. Add enough water to moisten, but not enough to create puddles. 3. Place the ants in the aquarium. Secure the top on the aquarium so the ants cannot escape. 4. Prepare sweet, sour, bitter, and salty solutions and the control. To do so: a. Label one baby food jar sweet, one sour, one bitter, one salty, and one control. b. Half-fill each baby food jar with water.

3 ANT PREFERENCES 3 c. To the jar labeled sweet, add 1/2 tsp of sugar and stir until dissolved. d. To the jar labeled sour, add 1/4 tsp of citric acid and stir until dissolved. e. To the jar labeled bitter, add 1/4 tsp of caffeine and stir until dissolved. f. To the jar labeled salty, add 1/2 tsp of salt and stir until dissolved. g. Do not add anything to the control jar. 5. Label two pieces of aluminum foil sweet, two sour, two bitter, two salty, and two control. What You Do: Day 2 1. Slice the bread into 10 cubes, each about 3 cm 3 cm. Place each cube on a piece of aluminum foil. 2. On the aluminum foil square labeled sweet, place 10 drops of sweet solution on one side of each piece of bread. Turn over each piece of bread and place 10 drops on the other side. 3. Repeat steps 2 and 3 for the sour, bitter, salty, and control solutions. 4. Place all 10 squares of aluminum foil and bread in the aquarium. 5. Observe the responses of the ants to each piece of bread (Figure 1). Every 15 minutes, for the next 45 minutes, count the number of ants feeding on each piece of bread and record those numbers in a data table of your own design. ant colony bread Figure 1

4 ANT PREFERENCES 4 Observations 1. In this experiment, water is the control. What is the purpose of an experimental control? 2. In any experiment, the hypothesis is a statement of what you think your results will be. What was your hypothesis in this experiment? 3. According to your experimental results, which flavor do ants prefer? 4. Based on your experimental results, what kinds of food would you avoid on a picnic? Want to Know More? See Our Findings.

5 SAFETY PRECAUTIONS Review Before Starting Any Experiment GENERAL Always obtain your teacher s permission for experiments performed at school, and your parent s permission for experiments performed at home, before attempting any experiment. Read all instructions for an experiment before starting the experiment, and follow the directions exactly as they appear in this volume. If an experiment requires adult supervision, do not perform the experiment unless you have an adult supervising you the entire time you are performing the experiment. Wash your hands before the start of and after each experiment you perform. Keep your work area clean. Never eat or drink while performing an experiment. Never taste a substance used in an experiment unless you are told that it is safe to do so. Be aware of the location of safety equipment you may need in an emergency, such as running water, an eyewash if you are at school, and a fire extinguisher. If you are going outside, make sure you have permission to go from your teacher and parent. Take a buddy with you, and dress appropriately for the weather. Make sure you or someone who accompanies you is familiar with the area, and bring along a firstaid kit in case of emergency. Never look directly into the Sun. CHEMICAL SAFETY Always wear goggles when working with chemicals, such as acids and bases, and near heat sources like flames. If at all possible, avoid wearing contact lenses when working with chemicals. If any substance gets into your eyes, notify an adult (e.g., your teacher or parent) immediately, and flush your eyes with running

6 SAFETY PRECAUTIONS 2 water for at least 15 minutes. Do not mix chemicals unless you are told to do so by a teacher or parent. Never touch, taste, or smell chemicals unless instructed to do so. Keep chemicals in closed containers when they are not in use. Dispose of all chemicals properly. Do not pour any chemicals or solids down the drain unless instructed to do so. Use safety gloves and a plastic apron when handling chemicals. If any chemicals spill on your skin, rinse the affected area with running water for at least 10 minutes, and notify your teacher or parent immediately. Take precautions to avoid spilling chemicals. If a chemical spills on any surface, notify your teacher or parent immediately to assist with clean-up. Exercise caution when using sharp instruments such as knives or scissors. Always cut away from yourself, not toward yourself. If you cut yourself, notify your teacher or parent immediately. GLASSWARE Clean glassware when you are finished with the experiment. Be careful when using glassware. If a piece of glassware breaks, have an adult assist you in clean-up to avoid injuries from broken glass. Never use broken or damaged glassware. FIRE SAFETY Do not heat glassware that is not completely dry. Do not pick up hot glassware without heat-resistant gloves or tongs. When heating glassware, keep it away from yourself and from others. Do not heat anything unless instructed to do so by a teacher or parent. Do not heat substances in a closed container. After an experiment, make sure that all heating sources are off and that all flames have been put out.

7 SAFETY PRECAUTIONS 3 Do not reach across such heating sources as flames. If you have long hair, tie it back, out of the way. Do not wear clothing with loose sleeves, scarves, bows, ties, or anything else that may hang into a fire. Do not wear long earrings. ELECTRICAL SAFETY Do not touch electrical equipment when your hands are wet. Do not plug several electrical devices into one outlet or use an extension cord.