AnimalBehaviorOncampus(1)

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Animal Behavior (on-campus version) Copyright © 2023 by Jeff Carmichael, Ph.D. University of North Dakota Name: Pauline Miñoza (if instructed by your lab TA to submit as a team, then include names of all team members WHO WERE PRESENT AND CONTRIBUTED TO THE LAB ACTIVITY here): If you were instructed to submit as a team and you are the recorder, place an “X” on the red line to indicate that this submission is the one that should be graded (only one student per team should place an “X” here): Unless indicated otherwise by your lab TA, all students must submit the completed lab to receive credit. Learning Objectives: After completing this lab you should be able to: 1. Use the scientific method to devise and experiment and test hypotheses regarding environmental preferences of pill bugs ( Armadillidium ) Perhaps one of the most interesting fields of biology to study is ethology, the study of animal behavior. It is important for an ethologist to investigate and interpret the various animal behaviors observed in terms of the animals’ reaction to their own environment. It is too easy to view animal behavior in terms of human habits; if a behavior seems to emulate a behavior that humans perform, it is interpreted as a human interaction. This anthropomorphic view (anthro = human, morph = change)—bestowing human traits and motivation on animals’ behavior—can lead to inaccurate interpretations of the animals’ behavior. Ethology can be considered a unique branch of biology, investigating not only what behaviors animals display, but also why they display them. In every ecosystem, organisms are influenced by limiting factors, both biotic and abiotic, which regulate the maximum size of a given population. There tends to be a relatively narrow range of environmental conditions that are favorable for specific species. Since most organisms cannot change the nature of their environment, they must position themselves in an environment with favorable conditions. This behavior is called habitat selection. Many organisms exhibit a tactic response to these environmental factors. Tactic responses may be positive, toward a favorable environment, or negative, away from an 1

unfavorable environment. These tactic responses enable an organism to locate prey, avoid predation, seek shelter, or avoid a toxic environment—all vital to habitat selection. An animal’s orientation behavior, which allows an animal place itself in a favorable environment, occurs in two ways: taxis and kinesis. Taxis is a deliberate movement toward or away from a stimulus. Kinesis, on the other hand, is a random movement that is not oriented toward or away from a stimulus. A movement classified as taxis defines the physiological needs of the organism. For example, an insect found around rotting fruit has most likely responded to a very different environmental stimulus than one found around a decaying corpse. As part of today’s lab, you will:  Observe and note general behavior characteristics of pill bugs.  Hypothesize as to whether pill bugs have adapted to perceive and react to certain environmental changes.  Analyze data to determine how pill bugs respond to environmental changes. You have undoubtedly seen pill bugs at some point in your life. These are commonly found under rocks and logs. Although the superficially resemble insects, they are actually crustaceans, a group which also includes crabs and lobsters. PART 1- Observing Pill bugs To become familiar with these organisms, use the Internet to find images of Armadillidium. 1. ? Do they have eyes? They have compound eyes made up of 15 to 20 eyes. They cannot see but they can sense light. 2. ? What might the antennae be used for? They are used to detect stimuli around their environment. 3. ? How do you think they “breathe”? They breathe through their gills. 4. ? Is their body relatively thick and solid, or more concave? Their body looks relatively solid. PART 2- Basic Pill bug Behavior You have pill bugs as well as the materials available in lab which include:  filter paper disks  choice chambers, which are essentially two Petri dishes joined by a connecting tube in the middle  Aluminum foil  Separate Petri dish  Brush and scoop  Water, KOH (alkaline), and HCl (acidic). 2

5. ? Explain how you could observe basic pill bug behavior and test whether they prefer one side of the choice chamber or the other using just the choice chamber, filter paper, and pill bugs? In this particular instance you’ll be keeping both sides of the chamber the same and will not introduce any environmental variables. Be sure to include enough detail so that your experiment could be repeated by someone else and mention what data you would collect and how you would analyze the data. An equal amount of pill bugs will be placed in two separate sides of the chamber and every couple of minutes, the number of pill bugs on each side will be counted and observed. Next, let’s run an experiment to see if pill bugs prefer one side or the other when conditions on both sides are kept the same. Procedure: Place five pill bugs in each side of the choice chamber. Every minute for 10 minutes, count the number of pill bugs in each chamber. Record your observations in the table below. Calculate the average number of pill bugs in each chamber over the 10 minute time period. Enter the results in the table below. Pill Bug Data Time (min) # Pill bugs in Side A # Pill bugs in Side B 0 5 5 1 5 5 2 7 3 3 7 3 4 7 3 5 6 4 6 5 5 7 6 4 8 3 7 9 7 3 10 7 3 Avg. 5.9 4.1 6. ? Do the pill bugs seem to prefer one side versus the other? Explain. Pill bugs prefer side A. The pill bugs seem to be gravitated towards side A. Side A has an average of 5.9 pill bugs, while side B has an average of 4.1. Your response to the previous question is largely a subjective one- you probably just looked at the average and asked yourself if they are “close enough” to be considered comparable. One 3

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statistical test that we could use to systematically test whether the means are significantly different between to different groups is the t -test. This statistical test takes into consideration sample size, average, and variation to test whether any difference in the means of two groups is likely caused by chance or some other factor. Although the formula for a t -test analysis is fairly straightforward, we won’t include that as part of this activity. Instead, you will use an online t - test calculator. Go to the following Internet site: https://www.graphpad.com/quickcalcs/ttest1.cfm Choose the following:“Enter or paste up to 2000 rows” Enter your data from the previous table. Group one will be the numbers for side A, group two will be the numbers for side B. Choose unpaired t test. Choose calculate now. 7. ? What P value is reported? Is the difference between the two means significantly different? Based on your t -test, do the pill bugs prefer one side versus the other? Explain. 0.0038. The difference between the two means is significantly different. Based on the t-test the pill bugs prefer side A more than side B. In essence, this P value represents the probability that any difference between the means of the two groups is due to random sampling events. In this case, the smaller the P value, the more likely the means of the two groups are significantly different. It is fairly common to use 0.05 as the threshold value (a P value lower than 0.05 is considered significantly different). Note that if you were communicating results of your experiment with others, you could use a t -test (or some other statistical test) to incorporate explicit criteria that were used to test whether or not the means of two groups are different (you wouldn’t have to rely on your subjective opinion). PART 3- Environmental Preferences We will investigate three environmental factors that affect pill bug behavior, including phototaxis, chemotaxis, and hydrotaxis. Phototaxis refers to the orientation of an organism in relation to the presence of light. Movement toward a light source is positive phototaxis; movement away from light is negative phototaxis. Chemotaxis refers to the orientation of an organism in relation to the presence of a particular chemical. Chemotaxis is universal in protozoa and most organisms; they avoid most chemicals but do exhibit a positive taxis toward others. Hydrotaxis refers to the orientation of an organism in relation to the presence of water. 4

Hypotheses Formulate hypotheses regarding environmental preferences and how the pill bugs may react to different conditions. Enter your hypotheses below regarding how you predict pill bugs will react to light, chemicals (acids and bases), and water. 8. ? Hypothesis regarding movement toward light: The pill bugs will move away from the light. 9. ? Hypothesis regarding movement toward water: The pill bugs will move away from the water. 10. ? Hypothesis regarding movement toward acids: The pill bugs will move away from the acid. 11. ? Hypothesis regarding movement toward bases: The pill bugs will move towards the base. Experimental Design Given the materials provided above in Part 2, design experiments to test each of your hypotheses. Explain your experimental setups below. Be sure to include enough detail so that your experiment could be repeated by someone else and mention what data you would collect and how you would analyze the data. 12. ? Description of e xperiment regarding movement toward light: An equal amount of pill bugs will be placed in opposite sides of a chamber. One side of the chamber will be covered with aluminum foil to hinder the presence of light while the other will have exposure to light. The number of pill bugs will be observed and counted every minute. Based on the average number of pill bugs per side, we can figure out which side they prefer better and whether or not they move toward or away from the light. 13. ? Description of e xperiments regarding movement toward acids and bases: An equal amount of pill bugs will be placed in opposite sides of a 5

chamber. One side of the chamber will have a few drops of acid while the other will remain the same. The number of pill bugs will be observed and counted every minute. Based on the average number of pill bugs per side, we can figure out which side they prefer better and whether or not they move toward or away from the light. The same procedure above is done for the base. 14. ? Description of e xperiment regarding movement toward water: An equal amount of pill bugs will be placed in opposite sides of a chamber. About ten drops of water will be placed on one side of the chamber, while the other remains the same. The number of pill bugs will be observed and counted every minute. Based on the average number of pill bugs per side, we can figure out which side they prefer better and whether or not they move toward or away from the light. Procedure Once your team is comfortable with your experimental setup, run your experiments and record data in the space below. Note: Be sure that there is only one possible variable present in your experiment. Multiple variables will invalidate your results and conclusions. Results, Conclusions, and Discussion Blank tables are provided below for your convenience. Phototaxis: Pill Bug Data Time (min) # Pill bugs in Side A # Pill bugs in Side B 0 4 6 1 7 3 2 6 4 3 8 2 4 9 1 5 5 5 6 6 4 7 4 6 8 5 5 9 6 4 10 6 4 Avg. 6 4 6

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Conduct a t -test like you did for Part 2 above. 15. ? What P value is reported? Is the difference between the two means significantly different, and therefore, do the pill bugs prefer one side versus the other? The P value is 0.0066. The difference between the two means are significantly different therefore the pill bugs prefer side A which had presence of light. 16. ? Did your results agree with your hypotheses? Are you confident with your conclusions or would you need to conduct more tests? Explain. The results did not agree to the hypothesis but we are not overly confident with the conclusions because when we performed the control experiment, with no additional variables to each side, the pill bugs still preferred side A. 17. ? Explain how these results relate to pill bugs in their natural environment. Include a discussion of how the environmental preferences observed today would be beneficial to pill bug growth and survival out in nature. Pill bugs, which are usually found under rocks and logs, prefer darker areas. By staying in darker and moist areas, they avoid extreme temperatures which help them to survive. Hydrotaxis: Pill Bug Data Time (min) # Pill bugs in Side A # Pill bugs in Side B 0 5 5 1 5 5 2 8 2 3 9 1 4 8 2 5 8 2 6 10 0 7 10 0 8 7 3 9 9 1 10 9 1 Avg. 8 2 7

Conduct a t -test like you did for Part 2 above. 18. ? What P value is reported? Is the difference between the two means significantly different, and therefore, do the pill bugs prefer one side versus the other? The P value is 0.0001. The difference between the two means are significantly different therefore pill bugs clearly prefer side A with the water more than side B. 19. ? Did your results agree with your hypotheses? Are you confident with your conclusions or would you need to conduct more tests? Explain. The results agree with our hypothesis. The P value is relatively small which makes us feel confident about our results and conclusion. 20. ? Explain how these results relate to pill bugs in their natural environment. Include a discussion of how the environmental preferences observed today would be beneficial to pill bug growth and survival out in nature. Pill bugs like to live in moist environment. They breathe through their gills so a moist environment is very beneficial. Chemotaxis (acids): Pill Bug Data Time (min) # Pill bugs in Side A # Pill bugs in Side B 0 5 5 1 1 9 2 4 6 3 6 6 4 5 5 5 6 4 6 6 4 7 8 2 8 8 2 9 7 3 10 6 4 Avg. 5.6 4.4 Conduct a t -test like you did for Part 2 above. 21. ? What P value is reported? Is the difference between the two means significantly different, and therefore, do the pill bugs prefer one side versus the other? The P 8

value is 0.1441. The difference between the two means is not significantly different. Based on the results, the pill bugs prefer side A with the acid. 22. ? Did your results agree with your hypotheses? Are you confident with your conclusions or would you need to conduct more tests? Explain. The results do not align with our hypothesis. We are not confident without conclusions because the results do not seem to be agreeing with each other. 23. ? Explain how these results relate to pill bugs in their natural environment. Include a discussion of how the environmental preferences observed today would be beneficial to pill bug growth and survival out in nature. The results do not make sense and are inconclusive. Chemotaxis (bases): Pill Bug Data Time (min) # Pill bugs in Side A # Pill bugs in Side B 0 5 5 1 6 4 2 6 4 3 2 8 4 1 9 5 3 7 6 3 7 7 4 6 8 0 10 9 1 9 9

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10 0 10 Avg. 2.8 7.2 Conduct a t -test like you did for Part 2 above. 24. ? What P value is reported? Is the difference between the two means significantly different, and therefore, do the pill bugs prefer one side versus the other? The P value is 0.0002 . The difference between the two means is significantly different . The pill bugs seem to prefer side B with the base. 25. ? Did your results agree with your hypotheses? Are you confident with your conclusions or would you need to conduct more tests? Explain. The results agree with the hypothesis. We are not confident with our conclusion because the results don’t clearly seem to align. We could conduct more experiments with additional variables to produce better results. 26. ? Explain how these results relate to pill bugs in their natural environment. Include a discussion of how the environmental preferences observed today would be beneficial to pill bug growth and survival out in nature. Our data shows that pill bugs like the basic environment more than acidic. But our data is not completely reliable because they do not completely align. We can only conclude that we have observed that the pill bugs seem to move towards the side which is wet because they prefer wet environments that keep them moist. End of Lab 10

AnimalBehaviorOncampus(1)

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