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FSE10forensic entomologyTeachers: Activity InformationActivity 2– Structure and life cycle of flies.• PowerPoint FSE16• Placemat activity – review of previous lesson on features of insects – students writedown in their own place on the placemat the features of insects they can recall.ööööAs a group write the features in the centre.Ask one person from each group (numbered heads) to call out one featureonly. They must not repeat a feature a different group has called out (suggestticking off a feature as it is called out and adding anything they don’t have).Activity 3 - Classification ActivityUsing the key below, students will try and try and identify the following 5 insects:InsectWaspOrder: HymenopteraBraconid waspSpathius pallidus AshmeadAdult(s)Photo by Gerald J. Lenhard,www.insectimages.orgFlyOrder: DipteraHorse flyHybomitra cincta (Fabricius)Adult(s)Photo by Sturgis McKeever,Georgia Southern Universitywww.insectimages.org4

FSE10forensic entomologyTeachers: Activity InformationInsectGrasshopperOrder: OrthopteraGreen bird grasshopperSchistocerca alutacea (Scudder)Photo by Whitney Cranshaw,Colorado State Universitywww.insectimages.orgBeetleOrder: ColeopteraSunflower beetleZygogramma exclamationis(Fabricius)Photo by Whitney Cranshaw,Colorado State Universitywww.insectimages.orgMothOrder: LepidopteraPolyphemus mothAntheraea polyphemus (Cramer)Photo by Bonnie Dalzell,www.insectimages.org5

FSE10forensic entomologyTeachers: Activity Information• View the Anatomical Atlas of Flies produced by CSIRO Entomology – this is agreat online tool (needs Broadband access) using high resolution images thatgive wonderful detail of the anatomical structure of 4 major fly groups.http://www.ento.csiro.au/biology/fly/fly.html (February 2006)Activity 4 - Monitoring TemperatureIntroduce the activity of monitoring the minimum and maximum temperaturesfor each day. These data will be used in Activity 7: “Accumulated Heat”.If the school has a weather station get temperatures from the station OR measurethe classroom temperatures using a maximum/minimum thermometer ORcollect information about ACTUAL temperatures from the newspaper or web.Record data in Table 2.Table 2: Minimum and maximum temperatures for 5 consecutive days.DateTemperatureMaximum o C Minimum o C Average o C7

Table 4: Three definitions of assorted Forensic Entomology terms.FSE10forensic entomologyTeachers: Activity InformationCarefully read the definitions. Consider the definition that each expert group researched. In thecolumn “Your group’s definition”, write what you consider to be the best definition for each term.Forensic Entomology Term Definition 1 Definition 2 Definition 3 Your group’s definitionAccumulated HeatAccumulated heatinfluences thedevelopment of the insectThe total amount of heatrequired for an organismto develop from one pointin its lifecycle to anotherpoint.A certain amount ofheat, accumulated overtime, needed for someorganisms to grow.Degree daysThe amount ofaccumulated heat isexpressed as degree daysAverage temperature forthe day.One degree-day is theamount of developmentthat occurs in one day(24 hours) when thetemperature is onedegree above the lowerdevelopment threshold.Faunal SuccessionAnimals succeed oneanother in a definite,recognizable order.Insects arrive on a corpsein a predictable sequencedepending on the stagesof decomposition.The sequence of insectsarriving on a body.DetritivoreThe organism gets itsenergy form organicwastes and deadorganisms.An organism whosefood source is dead ordecomposed organicmaterials.Consume detritus, which isdead organic matter, andredistribute the materialreturning it to the soil.DecomposerObtain energy andnutrients from organicremains and waste.Decomposers secreteenzymes that breakdown organic matterand then their individualcells absorb break downproducts.Feeds on and breaks downdead plant or animalmatter.Post mortem interval Time of death of a person. The time that has elapsedsince a person has died.The time between whena person has died andwhen their body has beenfound.Physiological timeThe amount of heatrequired for an organismto complete it’sdevelopment.The measurement ofaccumulated heat overtime.Measure of how muchheat is required tocomplete a particularorganisms development.Lower developmentThresholdThe lowest temperature atwhich development canproceed.Temperature that belowdevelopment stops.The minimumtemperature fordevelopment.PoikilothermicPoikilothermic animalscannot maintain constantbody temperature.Animals that have a bodytemperature that varieswith the environment.Cold-blooded animals.11

FSE10forensic entomologyTeachers: Activity InformationActivity 7 – Accumulated heatFSE04Analogy: Ask students to think about the steps inbaking a cake. The oven must be set at a certaintemperature--and the cake must remain in the ovenfor a certain length of time--in order for it to bakeproperly. A cake placed in a cold oven won’t bake nomatter how long it remains there.Ask students how the requirements for baking a cakemight be similar to the needs of growing organisms.See if they can develop the analogy to explain thatit takes a certain amount of heat, accumulated overtime, in order for some organisms to grow.Also, just as a cake requires a certain temperature forproper baking, there’s a threshold temperature atwhich organisms begin to grow. This is called the basetemperature or lower threshold temperature.The base or threshold temperature varies betweentypes of organism, for example plants and animalsand also between species.Insects are cold blooded or Poikilothermic and arehence reliant on the environmental temperature.In this activity the lower threshold temperature isconsidered to be 10 o C.Suggested Activity:Measure the Maximum and Minimum Air TemperatureEach Day.• This is an extension of Activity 3: MonitoringTemperature, Table 2.• Transfer the temperature data from Table 2 toTable 5.• Calculate the Amount of Heat Accumulated eachday.• Use as the lower threshold temperature 10 o C.Note:ööSubtract the base temperature from theaverage daily temperature. These dailyunits of heat are called “Growing DegreeDays”.Particular insects have different temperature baseshowever 10 o C will be the designated the artificiallower threshold temperature.If the daily average temperatures are > 10 o C, thenthe degree-days for that day are equal to the Avetemperature subtract 10 o C.If the daily max and min temperatures are < than 10 o C,then the degree days for that day are = 0.If the average max and min temperatures are greaterthan 40 o C (upper temperature threshold), then thedegree-days for that day are 0.13

FSE10forensic entomologyTeachers: Activity InformationTable 5: Measuring the amount of accumulated heat, in units of Degree Days, by measuring the maximal andminimal temperatures of a minimum of 5 consecutive days.DateTemperatureGrowing Degree Day valueAccumulated Degree HoursThresholdMaximum o C Minimum o C Average o C Temperature o C Ave temp –threshold temp DD x 24 hoursEg 25 12 18.5 10 18.5 – 10 = 8.5 8.5 x 24 = 204 ADH1010101010101014

FSE10forensic entomologyTeachers: Activity InformationActivity 8 – Food webs• FSE04, FSE06, FSE10, FSE12• Suggested activity• Cards with names of organisms• Paper punch• Ball of string• Scissors1. Write the names of various plants and animals(a variety of types) on index cards. You canuse the list below, construct your own, or haveparticipants select their own organism. Be sureto include the sun, plants, plant eaters, and flesheaters in the array. For example:sun, grasshopper, kookaburra, grass, blow fly, hawk,dandelion, mouse, worm, rabbit, cow, flea, wheat, tick,fox, weeds, dingo, fungi (mushrooms), microscopicbacteria, maggot, beetle, moth, sheep2. Punch holes in each card and give eachparticipant a card and a piece of string to hangthe card around his/her neck.3. Have individuals identify energy (or food) sources.As each one is identified, pass a ball of stringbetween the two people. For example: onestudent is a cow, and one is the grass. The cow willtake the ball of string, hold onto one end of thestring and pass the rest of the ball to the grass.8. After discussing the food web, the leader couldask what would happen if a species were removedfrom the web.a. Have a student pull on the strings they hold;anyone who feels a tug is directly affected bythat organism.b. Those “organisms” affected directly could thenpull on their strings and more organisms areaffected. Have different students pull on theirstrings.c. When the “sun” pulls on its string, everyoneshould be affected.d. Have some organisms drop their string(become extinct) and see who is affected.Discuss what would happen if all of theDECOMPOSERS were removed.This activity was adapted from the 4-H Shooting SportsProgram.http://www.riverventure.org/charleston/resources/pdf/food%20web%20game.pdf4. The grass will hold onto the yarn and pass the restof the ball to “what it eats,” in this case, the sun. Besure that the sun is connected to all the plants.5. Once the string gets to the sun, cut it off, and startagain in another place.6. Continue building the web, making therelationships as complex as time and numbers ofparticipants allow. Define terms such as herbivore,carnivore, insectivore, decomposer, etc andinclude them in your web. Students can be in asmany chains as you have time for; they do nothave to be in all of the chains.7. Discuss the nature and complexity of the foodweb that is formed.15

FSE10forensic entomologyTeachers: Activity InformationActivity 9 – faunal succession• Faunal Succession Board Game – FSE17Activity 10 – Scenario• FSE10, FSE13• The students have, resources to analyse in theirCrime Dossier FSE13, PLUS they need to use theirobservations regarding the life cycles of flies fromActivity 4: Rearing flies (FSE11).• The following is the information that students havein their crime dossier – FSE13 however your versionhas the calculations done for you.Case IntroductionA man’s body (Mr X) was found in an outside locationin country east of Perth, around 10am on November11th 2006. The police attending the crime called DrIan Dadour, a registered forensic entomologist fromthe Centre for Forensic Science at The University ofWestern Australia, at 1pm on November 11 th 2006 andasked him to examine the corpse and help determinethe approximate time of death (Post Mortem Interval).• Adult insects flying over the corpse were collectedby a hand net and placed in a small container of70% ethyl alcohol.• Air temperature was measured – 23.5 0 C.• Collected approximately 2 dozen large maggots.• Examined clothing and collected some pupaefrom within the folds of the clothes.• Sampled soil from underneath the corpse.He also made observations about:• The vegetation near the body.• The direction of the sun.He left a small weather station at the crime scene tocollect weather data for the next 7 days.At the crime sceneDr Dadour started his work on the case on theafternoon of November 11th. He visited the crimescene and collected and noted the following.Figure 2: The Forensic Kit.Figure 1 Dr Ian Dadour at the crime scene.Figure 3: A Weather Station16

FSE10forensic entomologyTeachers: Activity InformationThe scene was clearly photographed and the time ofdata collection was recorded.When he returned to his office he contacted theclosest meteorological station to get a climatologicalreport of the weather of the preceding 2 weeks.AT THE LABORATORYNotes from the crime sceneDr Dadour made the following notes about the crimescene.• Most of the maggots were large 3rd instarmaggots.• No empty pupae cases were found.• There was only a small number of pupae found inrelation to the number of maggots.• The body was found in a damp, shady location.• There was a definite odour at the crime site.Processing the collected insectsDr Dadour did the following.• The larvae were visually identified as being 3rdinstar.• Approximately 1 dozen were killed in hotwater then transferred to 70% ethyl alcohol formicroscopy studies – identification of species.• Approximately 1 dozen larvae were reared at 24 o C.• All collected pupae were reared at 24 o C.• All of the adult flies and some of the maggots werepreserved in 70% ethyl alcohol.The largest sized maggot found at the crime scenewas identified as a late third instar maggot Luciliasericata. Dr Dadour noted that this maggot was at late3 rd stage because the maggot had regurgitated theirgut. This happens just before pupation.The lower development threshold was considered tobe 10 o C for all species.On the 17 th of November, Dr Dadour collected the datafrom the weather station left at the crime scene andentered the maximum and minimum temperaturesinto Table 6. He then calculated a correction factor (cf)for the temperature data. Applying a correction factoris necessary as the temperature at the crime scenemay be significantly different from the meteorologicaldata that is available.Table 1: The day and time of adult fly emergencesfrom the pupae and larvae being reared in thelaboratory at 24 o C. Species identification frommicroscopy studies is also included.Emergence date Time Number SpeciesCollected as pupae19th November 7.30am 10 Lucilia sericata20th November 10am 2 Lucilia sericataCollected as larvae24th November 11.30am 11 Chrysomya rufifacies25th November 8am 1 Chrysomya rufifaciesThe maggots and the pupae were kept in anenvironment at 24 o C and were allowed to developand hatch. Dr Dadour kept careful notes about whenthe adult flies emerged. See Table 1.Case NotesThe species of adult blow fly that were caught inthe hand net at the crime scene were found to beChrysomya rufifacies and Calliphora dubia. NO Luciliasericata were caught in the net at the crime scene. Thecollected pupae, that were reared in the laboratory,were found to be Lucilia sericata and the maggotsthat were collected off the corpse were identified asChrysomya rufifacies.17

FSE10forensic entomologyTeachers: Activity InformationYour task!Your task is to use the information from Dr Dadour’s case notes plus the information provided below in Tables 2-6 tocalculate PMI – when did Mr X die?There is a worksheet and some tips below to help you tackle this case.Information that you need!Table 2: The time of development from egg hatch to pupation of Lucilia sericata at 24 o C.Development stage ADH @ 24 o C Development time (hrs)Egg hatch 196 141st – 2nd stage 336 242nd – 3rd stage 336 24Late 3rd stage 280 20Table 3: The time of development from pupation to adult emergence of Lucilia sericata at 24 o C.Development stage ADH @ 24 o C Development time (hrs)Pupation – adult emergence 4032 288 (12 days)Table 4: The time of development from egg hatch to pupation of Chrysomya rufifacies at 24 o C.Development stage ADH @ 24 o C Development time (hrs)Egg hatch 294 211st – 2nd stage 420 302nd – 3rd stage 336 24Late 3rd stage 336 24Table 5: The time of development from pupation to adult emergence of Chrysomya rufifacies at 24 o C.Development stage ADH @ 24 o C Development time (hrs)Pupation – adult emergence 3696 264 (11 days)18

FSE10forensic entomologyTeachers: Activity InformationDay Min o C Max o C Ave 1 o CAve 3cf = 0.4Degree dayAve3-ldtADH(dd x 24hrs)1 14.6 21.9 18.3 18.7 8.7 208.82 10.7 23.9 17.3 17.7 7.7 184.83 10.9 29.8 20.4 20.8 10.8 259.24 18.4 25.1 21.8 22.2 12.2 292.85 16.7 31.2 24.0 24.4 14.4 345.66 19.0 31.9 25.5 25.9 15.9 381.67 18.8 26.0 22.4 22.8 12.8 307.28 14.8 27.0 20.9 21.3 11.3 271.29 15.3 26.9 21.1 Weather station data 21.5 11.5 276.010 16.2 22.3 19.3 Min Max Ave 2Differenceave1 –ave219.7 9.7 232.811 15.6 22.0 18.8 13.6 23.5 18.6 0.2 19.2 9.2 220.812 12.3 24.9 18.6 8.3 28.0 18.2 0.413 15.9 34.2 25.1 14.5 35.5 25 0.114 18.8 33.9 26.4 18.5 34.5 26.5 -0.115 17.8 29.4 23.6 16.3 37.1 26.7 -3.116 18.0 24.7 21.3 15.7 27.5 21.6 -0.317 16.2 24.6 20.4 12.1 28.2 20.2 0.218 14.5 29.2 21.9 13.7 SUM -2.619 14.0 24.8 19.4 12.2 AVE - cf -0.420 14.6 23.9 19.3 12.521 11.2 27.222 15.2 32.423 16.0 29.924 16.2 26.925 16.7 31.126 16.5 35.727 16.1 26.828 18.1 28.429 12.8 22.730 16.2 22.2November, 2006Table 6: Daily maximum, minimumand average temperatures in o C forNovember 2006.Data has been collected from PerthAirport. Temperature readings fromthe weather station left at the crimescene are also included.A correction factor has been appliedto the daily average. The correctionfactor has been calculated by thefollowing method: the average of thedifference between Ave1 (perth) andAve 2 (weather station). The resultantcorrection factor has been appliedto each daily average temperaturefrom Perth data for the days prior tothe body being found. Ave3 columnholds these data.Degree days have also beencalculated by subtracting the lowerdevelopment threshold (10 o C) fromthe corrected daily average (Ave3).ADH or accumulated degree hourshas been calculated: Degree days x24 hours.http://www.bom.gov.auNB: students are expected to completetheir own calculations.19

FSE10forensic entomologyTeachers: Activity InformationWorksheet and tips for solving the crime– when did Mr X die?Students need to calculate the following. Enter intoTable 6. (This has been done for you in the teacher’sversion).1. Average 1 – average daily temperature for themonth of November from Perth airport.2. Average 2 – average daily temperature from theweather station left at the crime scene for 7 days.3. The correction factor: the difference betweenAverage 1 and Average 2. Sum this value andthen divide by 7 to give the average differencebetween the average daily temperature for Perthand the average daily temperature at the weatherstation.4. If the correction factor is a negative value – theweather station average temperatures are higherthan the Perth temperatures: ADD the cf tothe Perth daily average temperatures. Put thecorrected Perth daily average temperature intothe column titled Average 3.5. If the correction factor is a positive value - – theweather station average temperatures are lowerthan the Perth temperatures: SUBTRACT the cffrom the Perth daily average temperatures. Putthe corrected Perth daily average temperatureinto the column titled Average 3.6. Calculate the degree days for each day inNovember BEFORE the corpse was found: i.e.1 st – 11 th November. [corrected daily averagetemperature – lower development threshold(10 o C)]. Enter this value for each day into thecolumn labelled Degree Day.7. Calculate the accumulated degree hours (ADH) foreach day – (Degree day x 24 hrs). Enter this valueinto the column titled ADH.8. Look at the timeline for the month of November.Some known information is already in thetimeline while other known information needs tobe added. The timeline may help you to visualisethe events.Using your calculations and the provided informationanswer the following.Lucilia sericata – a primary strike blow fly -what is known!Pupa collected from the crime scene.a. egg hatch → pre-pupation = 1148 ADHb. pupation → adult emergence = 4032 ADHc. totaL ADH for development = 5180 ADH (15.4days at 24 o C)Calculate the date for pupationPupa developed in lab for 7.5 days until emergence onthe 19th November.ADH for 7.5 days in lab conditions = 7.5 days x 336ADH/day in lab= 2630 ADHTo emerge after 7.5 days the pupa would haverequired:4032 – 2630 = 1402 ADH for pupation in the wild.Temperatures in the wild (pre-11 th September) varied.Based on the ADH calculations in Table 6, the ADHfrom 6 th November through to November 11th ismore than required for pupation. Therefore thelarvae would have pupated sometime during the 6thNovember.Calculate the date for egg depositionThe larvae pupated on 6th November.The ADH required for the development from egg topupation is 1148 ADH.Based on the ADH calculations in Table 6, the ADHfrom the 3rd November through to the 6th Novemberis 1280 – more than is required for development.Based on the above calculations, Mr X dies sometimeon the 3rd November 2006.see page 2120

FSE10forensic entomologyTeachers: Activity InformationChrysomya rufifacies – a secondary strike blow flywhatis known!Larvae (3 rd instar) collected from the crime scene.d. egg hatch → pre-pupation = 294 ADHe. pupation → adult emergence = 3696 ADHf. totaL ADH for development = 5082 ADH (15.1 daysat 24 o C)Calculate the date for pupationThe collected larvae pupated and emerged as adultsafter 13.5 days in the lab on the 24 th November 2006.The larvae pupated on the 12 th November.ADH for 11.5 days in lab conditions = 11.5 days x 336ADH/day in lab= 3864 ADHCalculate the date for egg depositionThe larvae pupated on 12 th November.The ADH required for the development from egg tolate 3 rd instar is 1386 ADH.Based on the ADH calculations in Table 6, the ADHfrom the 7 th November through to the 12 th Novemberis 1365 – sufficient for development.Based on the above calculations, eggs that arecollected as larvae on the corpse were laid on the 7 thNovember.Do the results from 2 different species support theestimated PMI of the 3 rd November?Lucilia sericata is a primary strike blow fly that willoviposit within 4 hours of a person dying. Theestimated date is the 3rd November – probablysometime during the day as blow flies are not active atnight. This fly is also generally found in urban habitats.Chrysomya rufifacies is a secondary strike blow flythat will oviposit within 4 days of a person dying. Theestimated time for egg deposition is the 7 th November.Chrysomya rufifacies is a fly that is found in both ruraland urban habitats.The murder zone is in a different location to the“dumping zone”. The murder zone would be in anurban setting while the crime scene is in the countryeast of Perth. The murderer would have shiftedthe location of the corpse sometime after the 3 rdNovember and the discovery of the body on the 11 thNovember.STUDENT QUESTIONS1. What day in November did Mr X die?2. What is your supporting evidence?3. Lucilia sericata was NOT one of the speciesthat was net caught over the corpse on the11 th November? Yet, collected pupa weresubsequently found to be Lucilia sericata.Chrysomya rufifacies were net caught at the crimesite AND were identified as the larvae that werefound on the corpse. How do you account forthis?4. How accurate do you think your calculations are?5. What are the limitations of this method forestimating PMI?6. What extra data would you need to provide amore accurate and precise PMI?7. Two species of blow fly were involved indetermining PMI for the crime: Lucilia sericataand Chrysomya rufifacies. Why would the forensicentomologist calculate information for bothspecies of fly rather than just one type of fly?8. Dr Dadour noted that the corpse was found in adamp and shady location. Would this informationhave any bearing on his calculations for PMI?Activity 11 – What happened?• Students share reconstructions and re-enactingwhat they think happened – when did the victimdie?• Students present their evidence.21

FSE10forensic entomologyTeachers: Activity InformationChrysomya rufifacieseggs laidCorpse foundpupae collectedlarvae collectedAdults emerge fromcollected pupaeLucilia sericataMurderLucilia sericataeggs laidLucilia sericatalarvae pupateCollected lavaepupatesAdults emerge fromcollected larvaeChrysomya rufifaciesDD =8.7 7.7 10.8 12.2 14.4 15.9 12.8 11.3 11.5 9.7 9.231 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 1ADH =209 185 259 293 346 383 307 271 276 233 221laboratory consistent 24 o C [ ADH= 336/day][278]22

FSE10forensic entomologyTeachers: Activity InformationANSWERS TO STUDENT QUESTIONS1. What day in November did Mr X die?3rd (November 2006)2. What is your supporting evidence?Lucilia sericata is a primary strike fly and ovipositswith 4 hours of a person dying. The estimateddate of 3/11/06 is based on calculations of insectdevelopment from pupae found on the body.Chrysomya rufifacies is a secondary strike flyand will oviposit with 4 days of a person dying.Estimated date of the eggs being laid is 7thNovember. Taken together the calculationssupport the date of the murder to be 3 November.3. Lucilia sericata was NOT one of the speciesthat was net caught over the corpse on the11 th November? Yet, collected pupa weresubsequently found to be Lucilia sericata.Chrysomya rufifacies were net caught at thecrime site AND were identified as the larvaethat were found on the corpse. How do youaccount for this?Mr X’s body was found in a country locale – noturban – however Lucilia sericata pupae were foundon the body. Lucilia sericata is usually found inurban habitats. This suggests that the corpse wasmoved from an urban to a rural setting severalhours after the murder.4. How accurate do you think yourcalculations are?Fair5. What are the limitations of this method forestimating PMI?There are several limitations:• only 2 species of flies are used in the calculations• there are no correction factors for shadeand or dampness affecting the rate of insectdevelopment• shade is known to affect faunal succession –some flies prefer shaded areas• the actual temperature at the suspected locationis not known• the faunal succession pattern of insects maynot be specifically known for the geographiclocation• the internal temperature of the corpse was notmeasured. This could affect the calculations forthe rate of insect development.6. What extra data would you need to provide amore accurate and precise PMI?Accurate PMI calculations depend on knowing3 main things: the order of and time length forspecific species of fly to reach the body and therate of development of each species.The order and time length and the rate ofdevelopment of specific species dependson variables such as the particular season,geographic location, position of body in termsof indoors/outdoors and above or below the soil,urban or rural areas and being in full sun or theshade (to name a few).7. Two species of blow fly were involved indetermining PMI for the crime: Lucilia sericataand Chrysomya rufifacies. Why would theforensic entomologist calculate informationfor both species of fly rather than just one typeof fly?Calculating information for 2 species of fly thatare known to behave within different timeframes(primary and secondary strike flies) provides aform of triangulation of data. If both calculationsindependently support the proposed datethe forensic entomologist would have greaterconfidence in the calculations.8. Dr Dadour noted that the corpse was foundin a damp and shady location. Wouldthis information have any bearing on hiscalculations for PMI?Potentially this information would affecthis calculations. For an insect to developthe temperature must remain between aminimum and maximum value. The shaded areatemperature would be lower than out in thefull sun. Dampness of the soil/area would alsopotentially affect the rate of development.23