Climate Change and Insect Development: Does temperature affect when butterflies emerge from their cocoons?

Transcription

1 Climate Change and Insect Development: Does temperature affect when butterflies emerge from their cocoons? Ashley Font National Science Foundation Graduate STEM Fellow in K-12 Education Sugar Creek Watershed K-12 Education Program The Ohio State University-Ohio Agricultural Research and Development Center 1

2 TABLE OF CONTENTS I. Quick Tidbits 3 II. Learning Objectives and Assessment... 4 III. Materials Required... 5 IV. Timeline and Suggested Background Information...6 V. Experimental Procedure... 7 VI. Discussion / bringing it back to climate... 9 VII. Ohio Science Academic Content Standards. 10 VIII. References/Resources...11 IX. Appendix... a. Instructor Sheet 1- Insect Metamorphosis..12 b. Instructor Sheet 2- Cold-blooded Animals..14 c. Backup data set for emergencies d. Temperature Datasheets

3 Quick Tidbits Teaching science in the classroom can be enhanced by using live specimens in the classroom. Insects are one avenue teachers may wish to explore in order to bulk up their lesson plans. Insects are ubiquitous and relatively easy to catch or to purchase. Despite many myths that keep people from exploring insects, they are not all bad and less than 2% are actually pests of concern to humans. Fear of insects is often learned. Using insects in the classroom is one way of countering some childhood fears of insects. Some topics insects can help teach are: o Symbiosis o Invasive/Exotic/Native species o Food Webs and Ecosystems o Differences in Habitats = Different insects o Niches o Health issues o Climate Change o Pollination 3

4 CLIMATE CHANGE and INSECT DEVELOPMENT Lesson Plan: Temperature effect on insect development Goal: To understand interconnectedness between temperature and insect development and discuss the potential effects of global warming on insects. Learning Objectives: By the end of this lesson, students will be able 1) to experience making detailed observations and collecting data during an experiment 2) to practice creating lab reports and writing scientifically 3) to determine, generally, what effect temperature has on the emergence of butterflies from their cocoons 4) to discuss the effects of a warmer climate on, not only insects, but the ecosystems they are a part of. 5) to consider the connection between human-induced warming and the results they ve discovered in the experiment Assessment of Learning Objectives: 1) The successful completion of experiment will require students to have made observations and to have collected data properly. 2) The completion of lab report will give students practice in scientific writing skills 3) The completion of the experiment will reveal the effects of temperature on butterflies to the students; the completion of lab reports will reveal to the teacher how well students understood results and effects of temperature\ 4) The lab reports will provide an avenue for discussing results and make connection between warmer climates and natural events; group discussions in class will reveal how well students understand the effects of a warmer climate on more than just insects 5) Class and group discussions will create opportunity for students to make the connection of human impact on climate change to the impact of climate on the natural world 6) Throughout lesson, teacher is encouraged to have students discuss critical thinking questions in groups and write down their answers on note cards. The teacher can either use these for participation points or read them anonymously to the class to facilitate conversation among the entire class. Suggested discussion questions are included. THE EXPERIMENT: You will be testing what effect different temperatures/climates have on the emergence of butterflies from their cocoons. By placing cocoons of the painted lady butterfly (Vanesa cardui) in one of 3 different tanks (hot, cold, and room temperature), your students will time how long it takes for butterflies to emerge from their cocoons. Will they come out earlier or later in hot temperatures? Cold? 4

5 Materials: 1) 3 tanks with lids a. Suggestions: 5-10gal. fish tanks, popup hampers 2) 3 thermometers a. Preferably thermometers that record maximum and minimum temperature as well as store information for multiple days in order to record over weekends 3) 1 Heating lamp for hot environment a. Reptile heating lamps, reptile heating element, desk lamp b. NOTE: test-run the hot tank for a few days to see how hot it gets. A glass tank will get hotter than a screen cage. Don t overheat. 4) Ice Packs, cooler with ice, or fridge to create cold environment a. If done in fall/winter, outside or cold window will also lower temperature of tank 5) At least 15 Painted lady caterpillars (Vanessa cardui) (Carolina Biological Supply $15 for 5) a. Make sure you buy ones that come in jars WITH FOOD otherwise you will have to buy caterpillar food mix or the plants they feed on. b. The more caterpillars, the better. Some caterpillars can die. Can do replicates if desired. c. Suggest to purchase caterpillars 6) Calculators 7) Elmer s white glue 8) Pieces of paper to label individual cocoons, approximately 1cm X 1cm. a. Write a number in pencil on them, 1 through n (n=number of caterpillars) 9) Tweezers/forceps 10) Scissors 11) Pencils/paper 12) Dental wick (or sponges-must have NO soap or chemicals) 13) Sugar-water mixture (½ to ½ ratio) or mix in sugar until no more dissolves 14) Squirt bottle with water and paper towels 5

6 Timeline: from start to finish this module can take a month or more because of time for caterpillars to pupate and emerge. Plan for 1 to 3 weeks for caterpillars to pupate before experiment can begin, and approximately days for butterflies to emerge after pupation (time depends on tank and temperatures used) Background information required: Teacher should have an understanding of: 1. Insect life cycle: metamorphosis, incomplete and complete metamorphosis (see InstructorSheet_1 in appendix). 2. Cold-blooded organisms (see InstructorSheet_2 in appendix) 3. Examples of effects of warmer climates on organisms i. Various sources are listed below describing recent discoveries related to warmer climate and changed behaviors and events of organism. Teachers are encouraged to share these articles as they are examples of current events that students should be able to keep up on in their own newspapers and online media 1. Insect feeding and temperature: 2. Insect population growth and warmer temperatures: 3. Migrating birds come earlier/ mistimed with insect food source: 4. Early arrival of butterflies in England: YwNQ%3D%3D 5. Cold-climate beetles must move higher to survive warming mountains 6. Mammal habitats changed in Michigan due to warmer seasons 6

7 The Experimental Procedure Teacher Preparations: Caterpillars must be ordered in advance. Living materials are most often shipped overnight or 2 day shipping. 3 different environments need to be set up for the cocoons. o HOT: Use heating lamp or other heating unit to increase the temperature in the hot tank. Aim for a temperature between 85 F and 95 F. If the temperature gets too high, the caterpillars could be damaged or die. Test the tank to see how hot your particular heating source makes the tank. Glass tanks will hold heat more than a cage. o ROOM TEMPERATURE: This tank should need no alterations. Use your classroom s room temperature for this setting (around F). o COLD: There are multiple ways one can cool this tank. If done in fall or winter, a cold windowsill can keep the tank cooler than the room. If the experiment is done in fall or spring, an open window or outdoor cage can also suffice. A refrigerator or cooler with ice packs also will suffice. Aim for a temperature below room temperature but above freezing so as not to kill the caterpillars. Set out data collection sheets for each tank (included in appendix) Decide whether you want students to collect twigs or plants for butterflies to climb onto once in tanks. Teacher may do this himself/herself as well. If in glass tank, at least lay some paper towels down or taped to side for emerged butterflies to climb on. Now that you have received your caterpillars and set up 3 tanks, you can begin! Experiment: 1. Introduce students to the experiment. What will they be doing? Why are there caterpillars on your desk? 2. Have students perform background research on: a. butterflies (painted lady butterfly=vanesa cardui) b. temperature affect on development 3. Follow instructions for care that accompany the caterpillars. 4. Monitor the caterpillars daily. You will need to keep track of the date of pupation. a. Students or teacher may take on this responsibility. It is important, so make sure it is done properly. 7

8 5. When 1 individual pupates A)Mark the cocoon with a number and B) record the date a. Example: Cocoon #1 pupated on: 10/2/2009 Because caterpillars will pupate over multiple days, it is necessary to mark which pupate when in order to calculate how many DAYS it takes to emerge in each tank from pupation to emergence. b. Marking cocoons: use forceps and glue small piece of paper with a number on it to the cocoon 6. Carefully move cocoon into one of the 3 tanks. a. 2 ways to best move them. You can carefully lay them atop some crumpled tissue as padding or you can cut out the area around the cocoon and tape it hanging from a branch or side of the cage. 7. Use the included datasheet or one of your own design to track: a. the days of incubation b. the daily maximum and minimum temperature in each tank. Have students record temperatures and monitor cocoons to collect their data. 8. When butterfly emerges note which cocoon number and the date 9. To feed adult butterflies: a. Make sugar water mixture (suggest 1 to 1 ratio sugar and water or what is included with instructions) b. Soak dental wick or sponge with mixture and place in dish with some excess fluid in the bottom. REMEMBER-do not use sponges with anti-bacterial or antimildew coatings. These could potentially be harmful to the butterflies. c. Replace every 1 to 2 days 10. When all emerge, you can decide which summary statistics are appropriate. a. Suggestions: i. Average days to emergence for each group; Average temperature per tank ii. Standard Deviation iii. Survival? Did any die? Which cages? 11. Finished? Painted lady butterflies can be released in Ohio. a. Other options: humanely dispose by freezing in ziplock bags Additional options: Calculate the growing degree-days accumulated from pupation to emergence. A degreeday is a measure of how much heat above a base temperature accumulated over a period of time. General degree-day formula is: (average daily temperature base temperature). The base temperature is generally 50 F. Find more information on degree-days here: You may choose to put the caterpillars in the tanks before pupation. This will allow the experiment to address how the temperature affects them from larva to adult. This minimizes complications in transferring cocoons. 8

9 For younger age groups, you may wish to go through life stages of insects and simply show which group emerges first without approaching statistics. Discussions: Alright, so we ve done an experiment to determine the effect temperature has on when butterflies emerge. How does this relate to climate change and our broader topic? What this experiment has illustrated on a small scale is that warmer temperatures over time can affect the natural world. In our case, that warmer climate in the spring or summer may cause butterflies to emerge earlier than they would have in a normal temperature. So the natural question is So what if butterflies come out a day or two early? Discussion points to focus on with students: What potential problems could occur for the butterfly by coming out early? Food sources or host plants are not bloomed yet? Weather may not be stable enough yet (sudden frost or cold spell?) What potential problem could occur for organisms that may depend on butterfly being on time? Birds that eat butterflies may not have migrated into area yet? Other animals that rely on butterflies later in season miss out on their food? Flowers that rely on butterfly for pollination may not bloom in time before butterfly dies or migrates on? What if the butterflies came out 2 days early every year for 10 years? If they lay their eggs 2 days early this year because they are out earlier, and emerge 2 days early the next year because of warmer weather the butterflies could end up emerging a little earlier each year over time (provided the weather stays warm enough) causing even bigger differences Bigger Questions what ifs and the hypothetical What about other bugs? What insects are more important? Bees Crop pests: damage to crops earlier in the season = crops have less chance of surviving the damage because they would be younger and have less vegetative material to lose to pests when the pest emerges earlier. Farmers would have to spray more? Or alter their planting schedules? Invasive and Exotic pests/plants/ and organisms as the weather changes, different insects and plants can survive where they could not before competing with native organisms 9

10 SUGGESTION: print off or project news articles from newspapers or online news websites which relate to the experiment. Ohio Academic Content Standards: s Indicators for Earth and Space Science: Grade 11 Indicator 12. Explain ways in which humans have had a major effect on other species. Benchmarks for Life Sciences: Grades Benchmark D. Relate how biotic and abiotic global changes have occurred in the past and will continue to do so in the future. Benchmark E. Explain the interconnectedness of the components of a natural system. Benchmark F. Explain how human choices today will affect the quality and quantity of life on earth. Indicators for Life Sciences: Grade 11 Indicator 9. Give examples of how human activity can accelerate rates of natural change and can have unforeseen consequences. Indicator 10. Explain how environmental factors can influence heredity or development of organisms. Indicator 12. Recognize that ecosystems change when significant climate changes occur or when one or more new species appear as a result of immigration or speciation. Grade 12 Indicator 8. Based on the structure and stability of ecosystems and their nonliving components, predict the biotic and abiotic changes in such systems when disturbed (e.g. introduction of nonnative species, climate change, etc.) 10

11 References and Further Sources of Information Mansfield L Migrating Birds Come Earlier, but Some may be Left Behind as the Climate Warms Rapidly. Eurekalert Online. Available from: McCarthy, M Early Arrival of Butterflies Demonstrates Impact of Climate Change. The Independent. Available at: Messer AE Ancient Leaves Point to Climate change effect on Insects. Eurekalert Online. Available from: Olson A. Does Temperature Affect the Rate of Butterfly Development? [Internet]. [Updated August 31, 2006]. Science Buddies Online. Copyright Kenneth Lafferty Hess Family Charitable Foundation Available from: Ross-Flanigan, N Climate Change Driving Michigan Mammals North. Eurekalert Online: Available from: Stone S Ice Beetles Impacted by Climate Change. Eurekalert Online. Available from: Stricherz V Insect Population Growth likely Accelerated by Warmer Climate. Eurekalert Online. Available from: The Open Door Website. 11

12 APPENDIX Instructor Sheet 1 Complete Metamorphosis Complete metamorphosis has an egg stage, larval stage, and pupation stage before reaching adulthood. These include: Hymenoptera: Bees, Wasps, Ants Lepidoptera: Butterflies, Moths, Skippers Coleoptera: Beetles Diptera: Flies Neuroptera: lacewings, antlions, Dobson flies Trichoptera: Caddisflies Siphonaptera: Fleas 12

13 Incomplete or Simple Metamorphosis ( ODWS Incomplete metamorphosis includes egg stage, nymph stage, and an adult stage. The nymph stage is simply an immature form of the adult but has no wings. These include: Odonata: Dragonflies and Damselflies Orthoptera: Crickets and Grasshoppers Heteroptera: True Bugs such as stink bugs, leaf-footed bugs, assassin bugs, As well as plant hoppers, aphids, etc Phasmatodea: walkingsticks and leaf insects Ephemeroptera: mayflies Etc. 13

14 Instructor Sheet 2 Cold-blooded Animals Cold-blooded animals take on the temperature of their environment. Unlike warm-blooded animals which convert food into energy and therefore heat, coldblooded animals cannot generate their own internal heat. Cold-blooded animals move faster at hot temperatures and are slower and less active at cool temperatures. The reason for the slow activity in cold environments is because their internal bodily functions require chemical processes which can be sped up or slowed down by temperature. Enzymes in the body which catalyze reactions are affected by temperature also. Heating up enzymes causes them to work faster and cooling them conversely slows them down. If it gets too cold or too hot, enzymes can shut down or be damaged. By slowing down enzymes, the chemical processes slow, and therefore activity and development also slow. Additional information can be found here: Hermans-Killman, L. Warm and Cold-blooded: The Infrared Zoo Cool Cosmos at the Infrared Processing and Analysis Center and the SIRTF Science Center. -Teaching lessons are also available at this site. 14

15 Hot Tank Room Temp Date Max Min Daily Average Date Max Min Daily Average 11-Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Avg Avg Cold Temp Date Max Min Daily Average 11-Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Nov Dec Dec Dec Dec Actual data collected by students during the experiment -Hot tank was heated by a reptile heating lamp above a glass 10 gallon fish tank. -Room temperature tanks were large jars kept in back of room away from lamp and windows. - Cold tanks were large jars kept on the windowsill of the classroom. The windows were poorly insulated which kept the jars nice and cool for the experiment. Temperatures are in Farenheit 15

16 Painted Lady Results Handout 1) How many days did it take each butterfly to emerge? How many cumulative degree days? Cocoon Tank Pupation Date Emerge Date # of Days 1 Room Nov.11 DEAD 2 Cold Nov.11 Dec Hot Nov.11 Nov Cold Nov.12 Dec Room Nov.12 Nov Hot Nov.12 Nov Room Nov.12 Nov Cold Nov.12 Dec Hot Nov.12 Nov Room Nov.12 Nov Room Nov.12 DEAD 12 Hot Nov.13 Nov Cold Nov.13 Dec Hot Nov.13 Nov Hot Nov.13 Nov Cold Nov.13 Dec Hot Nov.14 Missing Data Ignore 18 Cold Nov.14 Dec ) In the hot tank, what was the AVERAGE number of days it took for the butterflies to emerge? (*hint* add up the number of days of ONLY the hot tank cocoons and divide by the number of cocoons that were in the hot tank) ) In the room temperature tank, what was the AVERAGE number of days it took for the butterflies to emerge? (add up the days of ONLY the room temp. tank and divide by the number of cocoons that were in the room temp tank only.) ) If any cocoons have emerged in the cold tank, what was the AVERAGE number of days it took for the butterflies to emerge? ) What was the average temperature reached in each tank? Hot: F Room Temp: F Cold: F 16

17 You will need to print one of these off for a hot tank, for a room temperature tank, and for a room temperature tank. Label the sheets accordingly so they do not get mistakenly switched by students who are taking the data. ] Date Maximum Temperature Minimum Temperature Degree-days 17

18 Painted Lady Butterflies Pupation Date: the date that the caterpillar turned into a cocoon There are 20 caterpillars. When they turn into pupa, we have to number them because each caterpillar could have a different pupation date. Cocoon # Pupation Which Temperature Date of Cumulative Degree Days Date was it put in? Emergence on Date of Emergence EXAMPLE 11/7/2008 Hot Tank 11/20/