View
220
Download
1
Category
Tags:
Preview:
Citation preview
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
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
Recommended