Entomology Kit Climate Data & Calculations

Analysis Tutorial

Degree-Hour DeterminationA degree-hour is a unit of measure for charting insect growth. It

is just an expression for the amount of time spent at a specific temperature.

For example, flies that are incubated at 90 degrees for one hour will have the same level of development as those that are kept at 45 degrees for two hours.

90 degrees * 1 hour = 90 degree-hours45 degrees * 2 hours = 90 degree-hours30 degrees * 3 hours = 90 degree-hours

Actual Lab data

Species A Species B

Eggs 1

1st Instar 2

2nd Instar 1 2

3rd Feeding3rd Migrating

3

Pre-Pupae

Pupae

Adult 2

Species A Species B

Eggs 1

1st Instar 3 1

2nd Instar 5 2

3rd Feeding

3

3rd Migrating

4

Pre-Pupae

Pupae

Adult 4 1

Adult Woman in Cabin Adult Man in Cabin

3rd Instar Migrating were the most developed larvae from Species A and 2nd Instar were the most developed from Species B. The adult flies from each species represent those laying eggs NOT adults resulting from a full life cycle.

Degree-Hour DeterminationKnowns• Bodies discovered at 1:00PM on June 20• Insects collected at 3:00PM on June 20• Weather type (sunny, partly cloudy, overcast)• Weather events (rain, thunderstorms, snow)• Daily average temperature• Male and Female had the same species and lifecycles present

(Migrating 3rd Instar Species A, 2nd Instar Species B)Unknowns• Elapsed degree-hours for each day• Degree-hours for each life stage of both species• Cumulative degree-hours for each life stage of both species• Average Temperature for the month of June• Which day the adult insect from both species laid its eggs (PMI)• Earliest and latest time the insects began developing

Elapsed degree-hours for each day

• Every daily average temperature in the month will be multiplied by 24 except June 20.

• The collection time was 3:00PM on June 20, this tells us to multiply the average temperature on this day by 15 hours (12:00AM through 3:00PM = 15hrs) instead of 24 hours

Lab Procedure 2, Step 2: Determine the number of degree hours for each day using the weather

service data. To do this, multiply the average temperature times 24 hours for each day. This can be

performed in a spreadsheet.

Elapsed degree-hours for each dayDAY AVG DEPAR-TURE

FROM NORMAL

DEPAR-TURE FROM NORMAL

HEATING COOLING TOTAL WATER EQUIV

SNOW-FALL, ICE PELLETS

SNOW, ICE PELLETS OR ICE

ON GROUND

AVG SPEED (MPH)

AVG SPEED (KPH)

SKY COVER SUNRISE-SUNSET

WEATHER OCCURENCES

PEAK WIND (KPH)

degree hours

1 13.2 -1.9 -1.0 2.2 0.0 0.00 0 0 6.3 10.08 6 0

S 18.7

386.666667

2 12.5 -3.0 -1.7 3.3 0.0 0.09 0 0 13.8 22.08 6 0

SE 26.2

360

3 12.8 -5.2 -2.9 5.6 0.0 0.19 0 0 17.2 27.52 8 5

SW 33.3

306.666667

4 12.5 -4.7 -2.6 5.0 0.0 0.28 0 0 12.3 19.68 9 1

W 38.6

320

5 13.2 1.4 0.8 0.0 1.1 0.00 0 0 11.1 17.76 7 1,2

W 28.3

466.666667

6 12.4 2.6 1.4 0.0 2.2 0.00 0 0 8.1 12.96 6 0

SW 24.3

493.333333

7 12.6 1.4 0.8 0.0 1.1 0.07 0 0 6.3 10.08 8 0

S 16.7

466.666667

8 14.7 -1.9 -1.0 0.0 0.0 0.11 0 0 13.2 21.12 8 0

S 27.9

386.666667

9 14.5 0.9 0.5 0.0 0.6 0.00 0 0 4.2 6.72 3 0

SE 10.3

453.333333

10 13.2 -1.9 -1.0 0.0 0.0 0.00 0 0 8.88 14.208 6 0

S 22.7

386.666667

11 13.1 -2.7 -1.5 0.0 0.0 0.67 0 0 19.6 31.36 6 3,5

S 32.4

367.2

12 14.2 -7.5 -4.2 0.0 0.0 1.13 T 0 23.5 37.6 8 1,3,5

SW 43.8

252

13 10.7 -5.9 -3.3 0.0 0.0 0.23 0 0 14.2 22.72 7 1,2

S 29.8

290.4

14 11.5 -3.0 -1.7 0.0 0.0 0.02 0 0 10.5 16.8 8 1

S 24.5

360

15 12.8 -5.2 -2.9 0.0 0.0 T 0 0 11.9 19.04 4 0

SW 23

306.666667

16 12.7 -4.7 -2.6 0.0 0.0 0.00 0 0 6.4 10.24 3 0

W 19.2

320

17 12.9 -5.1 -2.8 0.0 0.0 0.00 0 0 9.5 15.2 3 0

S 27.2

309.6

18 12.7 -1.6 -0.9 0.0 0.0 0.00 0 0 11.1 17.76 2 0

W 26.3

393.6

19 12.8 -2.1 -1.2 0.0 2.8 0.00 0 0 4.6 7.36 1 0

SW 17.8

381.6

20 12.9 0.4 0.2 0.0 5.0 0.00 0 0 7.4 11.84 1 0

W 23.1

276

                         

Degree-Hour DeterminationKnowns• Bodies discovered at 1:00PM on June 20• Insects collected at 3:00PM on June 20• Weather type (sunny, partly cloudy, overcast)• Weather events (rain, thunderstorms, snow)• Daily average temperature• Male and Female had the same species and lifecycles present

(Migrating 3rd Instar Species A, 2nd Instar Species B)Unknowns• Elapsed degree-hours for each day• Degree-hours for each life stage of both species• Cumulative degree-hours for each life stage of both species• Average Temperature for the month of June• Which day the adult insect from both species laid its eggs (PMI)• Earliest and latest time the insects began developing

Degree-hours for each life stage: Species A

Lab Procedure 2, Step 3: Determine the number of degree-hours required for each life stage of both

species. To do this, multiply the number of hours by the degrees Celsius given in the life cycle table.

Temp °C

Egg 1st Instar 2nd Instar Feeding 3rd Instar

Migrating 3rd Instar

Pupa

21 21 hrs 31 hrs 26 hrs 50 hrs 118 hrs 240 hrs

21 hrs *21˚C = 441 deg-hrs

31*21 = 651

26*21 = 546

50*21 = 1050

118*21 = 2478

240*21 = 5040

Degree-hours for each life stage: Species B

Lab Procedure 2, Step 3: Determine the number of degree hours required for each life stage of both

species. To do this, multiply the number of hours by the degrees Celsius given in the table.

Temp °C

Egg 1st Instar 2nd Instar Feeding 3rd Instar

Migrating 3rd Instar

Pupa

21 25 hrs 37 hrs 31 hrs 60 hrs 124 hrs 286 hrs

25*21 = 525

37*21 = 777

31*21 = 651

60*21 = 1260

124*21 = 2604

286*21 = 6006

Degree-Hour DeterminationKnowns• Bodies discovered at 1:00PM on June 20• Insects collected at 3:00PM on June 20• Weather type (sunny, partly cloudy, overcast)• Weather events (rain, thunderstorms, snow)• Daily average temperature• Male and Female had the same species and lifecycles present

(Migrating 3rd Instar Species A, 2nd Instar Species B)Unknowns• Elapsed degree-hours for each day• Degree-hours for each life stage of both species• Cumulative degree-hours for each life stage of both species• Average Temperature for the month of June• Which day the adult insect from both species laid its eggs (PMI)• Earliest and latest time the insects began developing

Cumulative degree-hours for each life stage: Species A

Lab Procedure 2, Step 4: By adding all the degree hours for each of the six life stages together, you

calculate the cumulative degree hours required for an adult fly to develop at 21°C.

Temp °C Egg 1st Instar 2nd Instar Feeding 3rd Instar

Migrating 3rd Instar

Pupa

21 21 31 26 50 118 240

Deg Hrs 441 651 546 1050 2478 5040

Cum. Deg Hrs

441

Cumulative degree-hours for each life stage: Species A

Lab Procedure 2, Step 4: By adding all the degree hours for each of the six life stages together, you

calculate the cumulative degree hours required for an adult fly to develop at 21°C.

Temp °C Egg 1st Instar 2nd Instar Feeding 3rd Instar

Migrating 3rd Instar

Pupa

21 21 31 26 50 118 240

Deg Hrs 441 651 546 1050 2478 5040

Cum. Deg Hrs

441 651+441 = 1092

Cumulative degree-hours for each life stage: Species A

Lab Procedure 2, Step 4: By adding all the degree hours for each of the six life stages together, you

calculate the cumulative degree hours required for an adult fly to develop at 21°C.

Temp °C Egg 1st Instar 2nd Instar Feeding 3rd Instar

Migrating 3rd Instar

Pupa

21 21 31 26 50 118 240

Deg Hrs 441 651 546 1050 2478 5040

Cum. Deg Hrs

441 651+441 = 1092

546+1092 = 1638

Cumulative degree-hours for each life stage: Species A

Lab Procedure 2, Step 4: By adding all the degree hours for each of the six life stages together, you

calculate the cumulative degree hours required for an adult fly to develop at 21°C.

Temp °C Egg 1st Instar 2nd Instar Feeding 3rd Instar

Migrating 3rd Instar

Pupa

21 21 31 26 50 118 240

Deg Hrs 441 651 546 1050 2478 5040

Cum. Deg Hrs

441 651+441 = 1092

546+1092 = 1638

1050+1638 = 2688

Cumulative degree-hours for each life stage: Species A

Lab Procedure 2, Step 4: By adding all the degree hours for each of the six life stages together, you

calculate the cumulative degree hours required for an adult fly to develop at 21°C.

Temp °C Egg 1st Instar 2nd Instar Feeding 3rd Instar

Migrating 3rd Instar

Pupa

21 21 31 26 50 118 240

Deg Hrs 441 651 546 1050 2478 5040

Cum. Deg Hrs

441 651+441 = 1092

546+1092 = 1638

1050+1638 = 2688

2478+2688=5166

Cumulative degree-hours for each life stage: Species A

Lab Procedure 2, Step 4: By adding all the degree hours for each of the six life stages together, you

calculate the cumulative degree hours required for an adult fly to develop at 21°C.

Temp °C Egg 1st Instar 2nd Instar Feeding 3rd Instar

Migrating 3rd Instar

Pupa

21 21 31 26 50 118 240

Deg Hrs 441 651 546 1050 2478 5040

Cum. Deg Hrs

441 651+441 = 1092

546+1092 = 1638

1050+1638 = 2688

2478+2688=5166

5040+5166=10206

Cumulative degree-hours for each life stage: Species A

Lab Procedure 2, Step 4: By adding all the degree hours for each of the six life stages together, you

calculate the Accumulated degree hours required for an adult fly to develop at 21°C.

Temp °C Egg 1st Instar 2nd Instar Feeding 3rd Instar

Migrating 3rd Instar

Pupa

21 21 31 26 50 118 240

Deg Hrs 441 651 546 1050 2478 5040

Accum. Deg Hrs(ADH)

441 651+441 = 1092

546+1092 = 1638

1050+1638 = 2688

2478+2688=5166

5040+5166=10206

Accumulated degree-hours (ADH) = Sum of degree hours at each stage = 10206

Now we will repeat the Accumulated degree-hours calculation for Species B

Cumulative degree-hours for each life stage: Species B

Lab Procedure 2, Step 4: By adding all the degree hours for each of the six life stages together, you

calculate the Accumulated degree hours required for an adult fly to develop at 21°C.

Temp °C Egg 1st Instar 2nd Instar Feeding 3rd Instar

Migrating 3rd Instar

Pupa

21 25 37 31 60 124 286

Deg Hrs 525 777 651 1260 2604 6006

Accum. Deg Hrs(ADH)

525 777+525 = 1302

651+1302 = 1953

1260+1953 = 3213

2604+3213 = 5817

6006+5817 = 11823

Accumulated degree-hours (ADH) = Sum of the degree hours at each stage = 11823

Degree-Hour DeterminationKnowns• Bodies discovered at 1:00PM on June 20• Insects collected at 3:00PM on June 20• Weather type (sunny, partly cloudy, overcast)• Weather events (rain, thunderstorms, snow)• Daily average temperature• Male and Female had the same species and lifecycles present

(Migrating 3rd Instar Species A, 2nd Instar Species B)Unknowns• Elapsed degree-hours for each day• Degree-hours for each life stage of both species• Accumulative degree-hours for each life stage of both species• Average Temperature for the month of June• Which day the adult insect from both species laid its eggs (PMI)• Earliest and latest time the insects began developing

Elapsed degree-hours for each dayDAY AVG

1 13.2

2 12.5

3 12.8

4 12.5

5 13.2

6 12.4

7 12.6

8 14.7

9 14.5

10 13.2

11 13.1

12 14.2

13 10.7

14 11.5

15 12.8

16 12.7

17 12.9

18 12.7

19 12.8

20 12.9

   

Average temp for the month = 12.9◦C

Degree-Hour DeterminationKnowns• Bodies discovered at 1:00PM on June 20• Insects collected at 3:00PM on June 20• Weather type (sunny, partly cloudy, overcast)• Weather events (rain, thunderstorms, snow)• Daily average temperature• Male and Female had the same species and lifecycles present (Migrating

3rd Instar Species A, 2nd Instar Species B)Unknowns• Elapsed degree-hours for each day• Degree-hours for each life stage of both species• Cumulative degree-hours for each life stage of both species• Average Temperature for the month of June• Which day the adult insect from both species laid its eggs• Earliest and latest time the insects began developing

Calculating the PMIPost Mortem Interval = ADH/Average actual temp = 2688/12.9

= 208 hours (divide by 24)= 8.68 days (multiply .68*24 for hours)= 8 days, 15 hoursUse the ADH from the Feeding

3rd Instar – species A because that is the maximum amount of

time needed (the ADH for 2nd Instar – species

B is only 1302 hrs)

Conclusion: Bodies have been dead for a minimum of 8 days, 16 hours

DAY degree hours

9 453.333333

10 386.666667

11 367.2

12 252

13 290.4

14 360

15 306.66666716 32017 309.618 393.6

19 381.620 276 

THUNDERSTORM

The post mortem interval was calculated to be 8 days, 16 hours, but we know that the storm occurred on the evening of the 11th, so we conjecture that the flies were active at least an hour on the 11th to give them time to lay the eggs, thus bringing our PMI to a minimum of 8 days, 16 hours. The actual PMI, which is unknown, may vary up to 12 hours more than this calculation due to weather. Students’ calculations may vary by up to a day later.

Post Mortem Interval = 8 days, 15 hours