DC醫(yī)學資料法醫(yī)昆蟲學第1頁/共77頁2Activity9.1

IntroductionofForensicEntomologyIntroductionofForensicEntomology(http://www.nhm.ac.uk/nature-online/nature-live/video-archive/videos/forensic-entomology/)(anon-linevideobyMartinHallofNaturalHistoryMuseumofLondon)(suggestedepisodeforvideowatching:00:00-16:27))第2頁/共77頁3TaxonomyofinsectsKingdom(界) Animalia(動物界)Phylum(門) Arthopoda(節(jié)肢動物門)Class(綱) Insecta(昆蟲綱)Order(目) X,Y,Z…Family(科) A,B,C,…Genus(種) D,E,F,…Species(屬) G,H,I,…第3頁/共77頁4TaxonomyofTrueFliesKingdom(界) Animalia(動物界)Phylum(門) Arthopoda(節(jié)肢動物門)Class(綱) Insecta(昆蟲綱)Order(目) Diptera(雙翅目)Family(科) Calliphoridae(BlowFlies) Sarcophagidae(FleshFlies) …Genus(種) …Species(屬) …第4頁/共77頁5TrueFliesofHongKong第5頁/共77頁6亞麻蠅HouseFly(Parasarcophagesp.)Source:HongKongInsects(2007)(FriendsoftheCountryParks&CosmosBooksLtd)GenusnameSpeciesname第6頁/共77頁7金蠅BlowFly(Chrysomyasp.)Source:HongKongInsects(2007)Source:HongKongInsects(2007)(FriendsoftheCountryParks&CosmosBooksLtd)GenusnameSpeciesname第7頁/共77頁8南亞寡鬃實蠅PumpkinFruitFly(Bactroceratau)Source:HongKongInsects(2007)(FriendsoftheCountryParks&CosmosBooksLtd)GenusnameSpeciesname第8頁/共77頁9Source:.au(PestsandDiseasesImageLibrary)Chrysomyamegacephala(紅頭麗蠅)(Bluebottle)第9頁/共77頁10Chrysomyamegacephala(FoundinHK)Order(目) Diptera(雙翅目)Family(科) Calliphoridae Genus(種)

ChrysomyaSpecies(屬)

megacephala第10頁/共77頁11Pupa6-10mmEgg2-3mmLifeCycleofaBlowFly(CompleteMetamorphosis)NOTTOSCALEAdultLarva1stinstar2-4mm2ndinstar5-8mm3rdinstar10-15mmSource:/第11頁/共77頁12Remarks:1stinstar1slitwithineachspiracle2ndinstar2slitswithineachspiracle3rdinstar3slitswithineachspiracleAmaggot(larvalstage)Posteriorbluntpart(spiraclesforbreathing)Anteriorpointedpart(mouthforeating)Twospiracles(eachwith3slits)3rdinstar

第12頁/共77頁13Thepuparialcaseisusuallyovalinshapeandchangescolourovertime.Thecolourofthepuparialcaseofdifferentblowflyspeciesvaries.第13頁/共77頁14ForensicEntomologyKitSource:/Search.aspx?k=Forensic+entomology+kit

(SIRCHIE)第14頁/共77頁15PMI(PostMortemInterval)PMI–thetimeelapsedsincedeathPMIusuallycorrelateswiththeageoftheoldestimmatureblowflystagedevelopingonthecorpse.Dependingonthespeciesoftheblowfliesandtheenvironmentsuchasambientairtemperaturethedevelopmentoftheblowfliesmaytakeseveralweeksormonths.第15頁/共77頁16Adeadbodyisarichsourceforcarrionanimalswhichincludeinsectsandotherarthropodssuchasbeetles.第16頁/共77頁17EffectoftemperatureontherateofdevelopmentofinsectsInsects(e.g.blowflies)arecold-bloodedanimalsandtheirlevelofactivityincludingthegrowthratedependsonthetemperatureofthesurroundingenvironment.Insectsrequireacertainamountofheatenergytodevelopfromonestageintheirlifecycletoanotherstage.Theheatenergyisrequiredfortheenzyme-controlledbiochemicalreactionsofinsects第17頁/共77頁18EffectoftemperatureontherateofdevelopmentofinsectsForfliestodevelopthetemperaturemustremainbetweenaminimumtemperature(minimumdevelopmentalthreshold)andamaximumtemperature(upperdevelopmentalthreshold)foracertainamountoftimeTheminimumthresholdtemperatureformanyflyspecies=10oC(generally6oCto10oC)Oneithersideoftheminimumthresholdtemperaturetheinsectwillnotdeveloportherateofdevelopmentwilldecrease第18頁/共77頁19ItisfoundthatrateofdevelopmentofinsectsisdirectlyproportionaltotemperatureThehigherthetemp.,thelesstimeneededforthedevelopmentofinsects第19頁/共77頁20第20頁/共77頁21AccumulatedDegreeHours/Days

ADH/ADDAccumulatedHeat[acombinationoftemperatureabovetheminimumdevelopmentalthresholdmultipliedbytime]ismeasuredasphysiologicaltime(“physiologicalenergybudget”),inunitscalleddegree-days(oD)ordegree-hours(ohr)ADH=(T-Tmin)oCXtime(inhr)ADD=(T-Tmin)oCXtime(inday)第21頁/共77頁22Eachinsectspeciesrequiresacertainnumberofdegree-days/degree-hourstocompleteitslifecycleTheamountofheatenergyrequiredforthedevelopmentofaspecificinsectspeciesisconstant(i.e.theADD/ADHfordevelopmentisspecificforacertaininsectspecies)TheADHfortheblowflyPhormiareginaandSarcophagabullataare5160ADHand8317ADHrespectively第22頁/共77頁23Asthetemperatureincreasesordecreases,thechemicalreactionsgoverningthegrowthofaninsect(blowfly)increaseordecreasecorrespondingly.However,thetotalamountofADHforablowflytoreachaspecificgrowthstageisthesamewhetherithappensquicklyathighertemperatureorslowlyatlowertemperature.第23頁/共77頁24Forinstance,thetotalADHfortheblowflyPhormiareginatodevelopfromtheeggstagetotheendof1stinstar=567.8ADHIftheeggsoftheblowflyarerearedat26.7oC,itwilltake34hoursfortheeggstodevelopintothebeginningof2ndinstar.ADHofthedevelopment=34(hr)X(26.7-10)oC=567.8ADH第24頁/共77頁25IftheeggsoftheblowflyPhormiareginaarerearedatalowertemperature,20oC,theflywillneedmoretimetodevelopfromtheeggstagetothebeginningof2ndinstar. (20-10)oCxYhrs=567.8ADH Y=56.78第25頁/共77頁26Referenceforthe

DerivationofADD/ADHGennard,D.E.(2007).ForensicEntomology:AnIntroduction.UK:JohnWiley&SonsLtd.第26頁/共77頁27Activity9.2

SimpleCalculationofADD

(Quiz1)1.UsingthedatabelowcalculatetheADDofaflyspeciesforday1and2. Minimumthresholdtemperature=10oC Averagetemperatureofday1=12oC Averagetemperatureofday2=14oC2.CalculatethetotalADDforthetwodays.第27頁/共77頁28Quiz1(Solution)1.Day1:ADD=(12-10)(degree)x1(day)=2degree-daysDay2:ADD=(14-10)(degree)x1(day)=4degree-days第28頁/共77頁292.TotalADD=2+4=6(degree-days)Remarks:Temperatureusuallyfluctuateswithinaday.Hence,themean(average)temperatureistakenforaday.第29頁/共77頁30Activity9.2(Quiz2)

ApplicationofADHtoinferPMI

Acorpsewasdiscoveredat10:00am,25September2009.MaggotsofPhormiaregina,ablowflyspecies(atthebeginningstageof2ndinstar),werepresentandcollectedbytheforensic.entomologistat11:00am,25September2009Ittakes34hours(26.7oC)torearPhormiareginafromtheeggstagetothebeginningof2ndinstarinthelaboratory.

第30頁/共77頁31AverageTemp.on25,24,23,22Sept.2009were20oC,21oC,22oC,18oCrespectively.EstimatethePostMortemIntervalofthedeadbody(i.e.Whendidtheblowflyfirstarriveatthescene?).第31頁/共77頁32Quiz2(Solution)Workingbackwards:TotalADHfromeggstagetobeginningstageof2ndinstarofthefly=34hrsx(26.7-10)oC=567.8ADHFor25Sept.2009(0:00am–11:00am)ADH=11(hr)x(20-10)oC=110ADHFor24Sept.2009(0:00am–12:00midnight)ADH=24(hr)x(21-10)oC=264ADH第32頁/共77頁33TotalADHfor25&24Sept.2009=110+264ADH=374ADHTherefore,therewere567.8–374ADH(i.e.193.8ADH)contributedfromdaysbefore24Sept2009LetYbethetimeintervalbetweenthetimetheflylaideggsonthecorpseandmidnight(24:00)of23Sept2009.(22-10)oCxY(hr)=193.8ADHY=16.15

(approx.16)Theflylaideggsonthecorpsearound8am(24-16=8)

on23Sept.2009第33頁/共77頁34ThePMIofthedeadisaround8amon23September2009.第34頁/共77頁35BasicAssumptionsinusingADH

tocalculatePMIBlowflieswilllayeggsonthecorpseassoonastheydiscoverthedeadbody.Weatherconditions(e.g.temperature)recordedatasitedistantfromthecrimescenereflecttheconditionsatthecrimescene.Surroundingairtemperaturesarethemajorfactorsaffectingtherateofthedevelopmentoftheblowflies.第35頁/共77頁36Whydoforensicentomologistsneedtocollectandrearblowflies?Aforensicentomologistwillcollectseveralspecimensofblowflyspeciesfoundatthecrimesceneforlateridentificationatalaboratorybecausethelarvaeofmanyblowflieslookmuchalike.Thelarvaewillberaisedinatemperature-controlledchamberuntilthefliesemergedasadults(fortheexactspeciesidentification)第36頁/共77頁37Manyfactorsotherthantemp.mayaffectdevelopmentofblowflies:BuriedbodiesBodiesfoundinenclosedspaces(e.g.aroom,awardrobe)BodiesexposedtosunBodiesinwaterBodiesinacarBodieswrappedwithacarpet,etc.第37頁/共77頁38SeasonsUrbanvsruralscenes第38頁/共77頁39Activity9.3

ApplicationofForensicEntomologytofindthePMIinaCrimeCaseCaseIntroduction

Awoman’sbody(MissDianaWong)wasfoundinabushatnoonon13thOctober2009.Dr.AndyTse,aGovernmentforensicentomologistwascalledbythepolicetohelpinvestigatethecrime.Dr.Tsearrivedatthecrimesceneat1pmthatdayandhistaskwastodeterminethetimesincedeath(PMI,PostMortemInterval)ofthevictim.第39頁/共77頁40AttheCrimeSceneDr.Tsecollectedsomeadultblowfliesflyingoverthecorpsebyahandnetandplacedtheminasmallbottlecontaining70%alcohol.Hemeasuredtheairtemperature(=270C).Healsofoundthatthereweresomelargemaggotsonthecorpse.Hethencollected2dozenlargemaggotsandputtheminacleanbottle.第40頁/共77頁41Healsofoundsomepupaefromtheclothesofthevictimandcollectedthepupaeinanotherbottle.Hetooksomesoilfromunderneaththecorpse.Henotedthatthecrimescenewaswetandshady.Finally,heleftasmallweatherstationatthecrimescenetocollecttheweatherdata(max.andmin.temperature)forthenext7days.第41頁/共77頁42AtthelaboratoryTheadultblowfliescaughtatthecrimescenewereexaminedanditwasfoundthatallofblowfliesbelongedtothespeciesChrysomyamegacephala.Theadultflieswerepreservedin70%alcohol.Mostofthemaggotscollectedwereidentifiedvisuallyas3rdinstarmaggots.第42頁/共77頁43Onedozenofthemaggots(larvaestage)werekilledinhotwaterandthentransferredto70%alcoholforidentificationofspecies.Theotherdozenofmaggots(larvaestage)wererearedat270Candallowedtodevelopandhatch.Noemptypupaecasesfound.Allcollectedpupaewerealsorearedat270Candallowedtodevelopandhatch.Remarks:Thenumberofpupaefoundfromthecorpsewassmallerthanthatofthemaggots.第43頁/共77頁44CaseNoteThelowerdevelopmentthresholdwasconsideredtobe100Cforallspeciesofblowflies.On19thOct2009Dr.Tsecollectedthedatafromtheweatherstationleftatthecrimescene.HeenteredthemaximumandminimumtemperaturesintoTable1a&1bfortheperiod13-19Oct2009.第44頁/共77頁45Themeteorologicalinformation(maximumandminimumtemperatures)inOct2009wasobtainedfromthelocalobservatorydepartmentandthecorrespondingmaximumandminimumtemperatureswerealsoenteredinTable1a&1b.第45頁/共77頁46Table1aLuciliasericataADHofthe13hours(13thOct.,00:00-13:00)第46頁/共77頁47Table1bChrysomyamegacephalaADHofthe13hours(13thOct.,00:00-13:00)第47頁/共77頁48Table2

Thedayandtimeofadultflyemergencesfromthelarvaeandpupaebeingrearedinthelaboratoryat270C.

Maggotsrearedinthelaboratorysince13thOct2009DayandTimeofAdultEmergences

NumberSpeciesofblowfliesCollectedaspupae21stOct2009(13:00)12LuciliasericataCollectedaslarvae(3rdlateinstar)29thOct2009(03:21)12Chrysomyamegacephala第48頁/共77頁49Table3

Developmentaldataforablowfly

(Chrysomyamegacephala)at270C

ThresholdMinimumTemperature:100C

StageDevelopmentTime(h)ADHEgghatch183061stinstar-2ndinstar305102ndinstar-3rdinstar721224Late3rdinstar1442448Pupation–adultemergence2343978Source:J.D.Wells,H.Kurahashi.Chrysomyamegacephala(Fabricius)(Diptera:Callipohoridae)development:rate,variationandimplicationsforforensicentomology,JapaneseJournalofSanitaryZoology,45(4):303-309.第49頁/共77頁50Table4

Developmentaldataforablowfly(Luciliasericata)at270C

ThresholdMinimumTemperature:100C

StageDevelopmentTime(h)ADHEgghatch11.82001stinstar-2ndinstar203402ndinstar-3rdinstar20340Late3rdinstar17.1290Pupation–adultemergence2594400TotalADH(eggadultfly)(5570)第50頁/共77頁51Task1

UsingtheprovidedinformationofthecrimecaseandtheadditionalinformationfromTables1a,1b,2,3and4calculatethePMI(PostMortemInterval)ofthevictim(i.e.whendidMissDianaWongdie?)accordingtothedatafromLuciliasericata.第51頁/共77頁52Task2UsingtheprovidedinformationofthecrimecaseandtheadditionalinformationfromTables1-4calculatethePMI(PostMortemInterval)ofthevictim(i.e.whendidMissDianaWongdie?)accordingtothedatafromChrysomyamegacephala.

第52頁/共77頁53Task1(Solution)

Luciliasericata(i)WhatisthetotalADHforthedevelopment(fromeggtoadultfly)?Ans.:200+340+340+290+4400=5570(ADH)(ii)Howmanydaysdidthecollectedpupaeneedforitsdevelopmentinthelaboratoryuntiladultemergence?Ans.:8days(Thetimegapbetween13thOct2009(1pm)and21stOct2009(1pm))第53頁/共77頁54(iii)CalculatetheADHofthepupationinthelaboratory.Ans.:8(days)X24(hours)X(27-10)(oC)=3264ADH第54頁/共77頁55(iv)HowmanyADHwouldaccountforthepupationinthewild?Ans.:FromTable4theADHforpupation=4400ADH,hencetheADHforpupationinthewild=4400–3264=1136ADH第55頁/共77頁56(v)Calculatethedateof

theeggdeposition.

Answer:FromTable4theADHrequiredforthedevelopmentfromeggtoendoflarvalstage=200+340+340+290ADH=1170ADH第56頁/共77頁57CheckingTable1aandaddtheADHbackwardfrom13th,12th,11th,10th,9th,etcsuchthatthesumofADHjustexceeds

1136+1170=2306ADH

第57頁/共77頁58SumofADHfromOct13,1pmto7thOct(00:00)=2231.5ADHSumofADHfromOct13,1pmto6thOct(00:00)=2657.5ADH>2306ADHy/24x426ADH+2231.5ADH=2306ADHy=4.20Theflydepositedtheeggson6thOct2009

(19:48)(usingthedata24-4.20))第58頁/共77頁59Luciliasericata第59頁/共77頁60(vi)WhendidMsDiannaWongdie?

MsDianaWongdiedon6thOct2009(19:48)(i.e.8pm).第60頁/共77頁61Task2(Solution)Chrysomyamegacephala

(i)WhatisthetotalADHforthedevelopment(fromeggtoadultfly)?

(SeeTable3)Ans.:306+510+1224+2448+3978=8466(ADH)(ii)Howmanyhoursdidthecollectedlarvae(at3rdlateinstar)needforthepupationstagebeforeemergenceasadultsinthelaboratory?(SeeTable2forthetimegapbetween13thOct2009(1pm)and29thOct2009(3:21))第61頁/共77頁62Answer:15x24+14+21/60=374.35hours第62頁/共77頁63(iii)CalculatetheADHrequiredforthestageofpupation(3rdinstar)andemergenceasadultsinthelaboratory.第63頁/共77頁64Answer:ADHrequiredforthestageofpupation(3rdinstar)andemergenceasadultsinthelaboratory=374.35(hours)x(27-10)(oC)=6364ADH第64頁/共77頁65(iv)CalculatetheADHoftheeggandlarvae(1stand2ndinstar)inthewild.Answer:8466ADH–6364ADH=2102ADH第65頁/共77頁66(v)Whatisthedateofeggdeposition(Chrysomyamegacephala)onthecorpse?第66頁/共77頁67Answer:CheckingTable1bthedateofeggdepositioncanbefoundbyaddingtheADHinthewild(13th,12th,11th,10th,9thofOct,etc.)andcomparingthesumoftheADHwith2102ADHCalculationofADHfrom13thOct(13:00)to7thOct 388.8x(y)/24+(352.8+357.6+313.2+302.4+297.6+219.05)ADH=2102ADH y=16 Chrysomyamegacephalalaideggsonthecorpseon7thOct(08:00))第67頁/共77頁68CalculationofADHfrom13thOct.(13:00)to7thOct.(08:00):388.8x(y)/24+(352.8+357.6+313.2+302.4+297.6+219.05)ADH=2102ADHy=16(i.e.Chrysomyamegacephalalaideggsonthecorpseon7thOct.(08:00)第68頁/共77頁69(vi)WhendidMsDiannaWongdie?Answer:7thOct2009(8am).第69頁/共77頁70Activity9.4

DiscussionQuestions1.WhatfactorswouldaffectthereliabilityoftheabovemethodsusedtocalculatePMI?第70頁/共77頁71Answer:EnvironmentalfactorsSeasonalchangesDailytemperaturesSunexposureDeadbodyinsideoroutsideabuildingDeadbodyimmersedinwat