You will complete an Entomological Lab based on an actual case using data involving blow flies. Blow flies have a specific pattern of development based on the temperature that can be used to approximate Post - ‐Mortem Interval. Accumulated Degree Hour, or ADH, refers to the measurement of the thermal input, or heat needed for insects to grow and develop. Because insects are cold - ‐blooded, they rely on the environment for heat and can only develop in certain temperatures. This lab involves analyzing and interpreting entomological data to calculate the ADH and applying that to a case in which the Post- Mortem Interval is unknown. This lab requires that you pay close attention to detail, use problem solving skills and follow directions very carefully. To help you through the lab, please use the helpful information below. Make sure that you read through ALL of the information before beginning so that you are not confused in the lab. You will need a piece of paper, a writing utensil and a calculator for this lab to assist you as you work through the various calculations. It may help to print out the lab to write on as you are completing it and then go back and type in your answers on the lab worksheets to submit to your teacher. You will complete calculations and analysis throughout the lab worksheets as indicated. Materials: Paper, writing utensil and calculator Procedure: 1. Read through “Blow Fly Introduction” and review the “Blow Fly Life Cycle”. You will notice that Blow Flies have 3 stages in their Larva development. These stages are known as “Instars”. In the lab, you will complete a table in which you will need to label all of the stages of the Blow Fly. Each Instar is labeled as 1 st Instar, 2 nd Instar, 3 rd Instar in chronological order. 2. Next, refer to “Entomology Worksheet” and complete as directed. In Table 1, it should be set up like this: From To Temperature Hours ADH Egg 1 st Instar 70°F 23 1 st Instar 2 nd Instar 70°F 27 2 nd Instar 3 rd Instar 70°F 22 3 rd Instar Pupa 70°F 130 Pupa Adult 70°F 143 3. Multiply the number in the temperature column on Table 1 by the hours listed in Table 1 for each row and put the answer in the column marked ADH. 4. In question 3, you are asked to find the total number of hours. You will find this by adding up all of the numbers in the Hours column. Write this number in the indicated space for #3a. Next, you will need to find out how many days that total number of hours represents. To do
this, divide by 24 (number of hours in a day). If you end with a decimal, multiply only the decimal amount by 24 to get the leftover number of hours. 5. For 3b, find the amount of ADH needed in your table to progress from 2 nd Instar to 3 rd Instar and divide that number by the given temperature of 77°F. 6. For 3c, you will need to find the amount of ADH needed (from Table 1) to progress from Pupa to adult. Next, you will take that number from your table and divide by the number of hours in 7 days. (Hint: multiply the number of hours in a day by the number of days). 7. Complete the rest of Entomology Worksheet using what you have learned about insects and ADH. 8. Next, Access “Student Worksheet: Climatological Data and ADH Calculation” and “Preliminary Local Climatological Data”. 9. For #1 on the student worksheet, review the climatological data document and see if you can determine which factors (the titles of the columns is a good place to start) might be important when thinking about insect development. List those factors you choose in #1 and discuss your reasons for choosing those factors in #2. 10. Complete Table 1 on the Student Worksheet by filling in the temperatures from the Local Climatological Data document. The hours, with the exception of Sept 22 which is already completed for you, should all be listed as 24 hours. 11. In the column of Table 1 labeled “Daily Ambient Thermal Energy”, you will place your calculations of temperature times hours. Example: For September 22, multiply 56°F times 17 hours to obtain 952. That result will be written in the Daily Ambient Thermal Energy column. Do this for the rest of the column. 12. In the ADH column, you are totaling all of the products you calculated in the Daily Ambient Thermal Energy column. Complete the calculations for all dates in the table. For example: Date Daily Ambient Thermal Energy ADH Sept 22 952 952 Sept 21 1488 952+1488= Sept 20 1488 2440+1488= 13. Read all of the information in question #4 on the student worksheet. In Table 2, calculate ADH at 80°F for 10 - ‐12 days and fill in row A with those values. To find ADH at 80°F, multiply the temperature (80) by the number of hours in a day (24) and the total number of days (10 for the column labeled 10 days, 11 for the column labeled 11 days and so forth). 14. In row B of Table 2, you are calculating the ADH that Dr. Krinsky introduced to the pupa he collected. The worksheet gives you the temperatures and the hours; you just need to total them and calculate the ADH from those hours. To do this, find the total hours he had the pupa until they emerged as adults: 9/22 at 5:00pm through 9/27 at 4:00pm 15. Now that you have the total number of hours, multiply it by the temperature supplied: 80°F. Place this number in all 3 columns on row B. 16. For row C, subtract. Row A - ‐ Row B= what you place in row C. 17. For Row D, consult the ADH column in table A on the Student Worksheet. Find the date which is the closest match to your row C Table 2 numbers. Those dates represent your estimate for
