Forensic Entomology BIOL-3330H Trent University PDF

Forensic Entomology BIOL-3330H Trent University David Beresford course outline slides 2-15 lab outline slides 16-22 essay and project outline slides 23-25 lecture slides 26-59 1 course outline GTAs...

Forensic Entomology BIOL-3330H Trent University David Beresford course outline slides 2-15 lab outline slides 16-22 essay and project outline slides 23-25 lecture slides 26-59 1 course outline GTAs Madeleine Barryte [email protected] Sydney Dam [email protected] Alexander Robertson [email protected] 2 hours are available if needed, but we will not always take 2 hours each week, only if needed (eg for demonstrations). A weblink to the audio of 2022 lectures will be posted to Blackboard. These are to help you only, and the lecture material will differ. I do not expect you to use these, 2 only if you find them useful as a way to revisit material. course outline 3 course outline 4 course outline 5 course outline 6 course outline 7 course outline 8 course outline 9 course outline 10 course outline 11 course outline 12 course outline 13 course outline 14 course outline 15 Lab 1 outline Lab 1 (5%) Biology 3330H In this lab you will part 1) you will identify 3 blow flies to species (or possibly genus) using each of the 3 different keys, one key for each specimen, part 2) make a list of blow flies found in the Peterborough area using three published keys, part 3) you will then write this report up and submit it. You must cite the keys used for this assignment. Two keys are 1) keys found in the Canadian Journal of Arthropod Identification http://www.biology.ualberta.ca/bsc/ejournal/ejournal.html the first is available here (key no.11): https://cjai.biologicalsurvey.ca/articles/mwr-11/ the second is here (key no. 39) https://cjai.biologicalsurvey.ca/articles/jwm-39/ and the third is found in Terry Whitworth’s 2006 article (Bird Blow Fly site: http://www.birdblowfly.com/whitworth.html ) in The Proceedings of the Washington Entomological Society, which can be found here: http://www.birdblowfly.com/images/Publications/Keys.pdf You must download these keys as pdf’s so you can get access to the page numbers, and use the pdf version for this lab, saving the pdf’s to your laptops. You need the page numbers for this, and you will need to cite both of these articles in your report, and add them to the Reference at the end or your report. 16 Lab 1 outline In text citations are: Marshal et al. 2011; Jones et al. 2019; Whitworth 2006 and full citations are: Marshall, S. A., Whitworth, T. and Roscoe, L. 2011. Blow flies (Diptera; Calliphoridae) of eastern Canada with a key to Calliphoridae subfamilies and genera of eastern North America, and a key to the eastern Canadian species of Calliphorinae, Luciliinae and Chrysomyiinae. Canadian Journal of Arthropod Identification No. 11, 11 January 2011, available online at doi: 10.3752/cjai.2011.11. Jones, N., Whitworth, T., & Marshall, S.A. 2019. Blow flies of North America: Keys to the subfamilies and genera of Calliphoridae, and to the species of the subfamilies Calliphorinae, Luciliinae and Chrysomyinae. Canadian Journal of Arthropod Identification 39: 191 pp. doi:10.3752/cjai.2019.39 Whitworth, T. L. 2006. Keys to the genera and species of blow flies (Diptera: Calliphoridae) of America north of Mexico. Proceedings of the Entomological Society of Washington, 108: 689–725. 17 Part 1 Identify 3 blow flies to species using a different key for each specimen. You must cite the keys used for this assignment. Get a specimen (1 at a time, you will do 3 in total) from the bench and bring it to your desk. Use a pinning stage and microscope to view the specimen. You will need to keep track of the steps you used for the keying out using each key. This way, if you make a mistake, another researcher can correct the error. 18  For the species name, you must give the genus, species epithets (in italics), the authority, and the date. For example: Phormia regina (Meigen, 1826) In this example Meigen is the author who first identified this animal, and this was published in 1826. The genus name was changed since that time, so Meigen is in italics. Another example: Calliphora livida Hall 1948 For this species, the fly still carries the name originally assigned by Hall. see the International Code of Zoological Nomenclature http://www.iczn.org/iczn/index.jsp and http://insectes-nuisibles.cicrp.fr/en/nomenclature-and-classification-insects Create a table for each fly with the following information on it. Do this using each of the three keys: fly data label ___________________ species __________________________ 19 Lab 1 outline part 2 Using all three different keys, make a list of the species that are known to be found in the Peterbrough area. In your list, identify which of the three keys indicate this information (page number), whether you used the map or text for the two CJAI keys, whether the species is rare or common, and if these are forensically relevant or not, and any important specialization information (habitat, prey). There is no need to say map or text for the Whitworth key, it is all text. Sort your list by genus, alphabetically. Identify each of the 3 keys by a shortform: Canadian Journal of Arthropod Identification no. 39 Jones et al 2019 Canadian Journal of Arthropod Identification no. 11 Marshall et al 2011 Whitworth 2006, Proc. Ent. Soc. Wash. these can be shortened to CJAI no. 39 CJAI no. 11 Whit 2006 20 Lab 1 outline For example, the species Lucilia illustris occurs around Peterborough, list it this way in your report: Lucilia illustris, Whit 2006 p 721; CJAI no. 39 map p 143; CJAI no. 11 map p 87; common, widespread, forensically important You may wish to use headings, you could do it this way: Species Whit 2006 CJAI no. 39 CJAI no. 11 Lucilia illustris, p 721 map p 143 map p 87 NOTES: common, widespread, forensically important In your report, include a brief introduction, the list as a table. and a literature cited section giving the citations of the three keys. 21 Lab 1 outline Part 3 Submitted Report. Include an Introduction 2 – 3 sentences telling us what you are doing (eg making a list of species likely to be found in the Peterborough area, and identifying 3 specimens); Material and Methods, the specimens, where you got them, the keys you used and the microscopes. Results and Discussion (as one section): your table and your identifications. Literature cited, cite the 3 keys. Submit this as a WORD file or PDF to the folder on Blackboard (email directly to either me, or one of the TAs if Blackboard is not working). The due date is two week from the lab (Sept 25, see schedule). That is it! 22 FROM THE OUTLINE New Trends or Case Studies Research paper (2200 to 2700 words) (10%) Students will write a review paper on some topic of forensic and entomological relevance, which includes an analysis of the published literature on this topic based on using publication records as data. Topics should reflect current trends, but can include historical studies as well. These must be approved by the course instructor, specific details will be provided during the lectures and in the lecture notes. Suitable topics include insects and decomposition, the attraction of flying insects to carrion, chemical ecology of maggots, maggot morphology and habitat, carrion vs live tissue and accidental myiasis, insect succession on a carcass, geographic and temporal variability of specific families (Calliphoridae, Silphidae, Dermestidae), insect developmental processes and temperature, microclimate temperatures and corpses, DNA and forensic entomology, insect sampling and sample biases. INSTRUCTIONS for the above assignment ESSAY (also known as) CASE STUDY PAPER (10%) This is a review on a topic of your choice, surveying the existing literature on this topic. References or citation or whatever you want to call them go in the text for example (Smith 2006). Of, if you prefer the numbered method, use this1 1) Smith, 2006 etc. As an example see the review in Annual Review of Entomology http://www.annualreviews.org/loi/ento or the reviews of mite research in the 2009 issue of Exp Appl Acarol. http://www.ncbi.nlm.nih.gov/pubmed/19609686 23 FROM THE OUTLINE Research project (10%) Students will design and conduct a research project, including relevance of the project, appropriate methods, and experimental design. This will be based on field collections or studies. Topics must be approved by the instructor. Examples of appropriate topicsare: blow fly attraction to different types of carrion, observer influence on the behaviour of blow flies at carrion, burying beetles and trap height, trap design, urban and rural habitats, surveys of forensic insects found near carrion. For these projects, dead animals carcasses will be deployed for student use. Each student will be expected to supply and/or construct any traps or equipment needed. INSTRUCTIONS I will be posting videos explaining how to make and bait your traps for your project. You write about where you set the traps, your data, and why this is interesting. RESEARCH PROJECT (10%) (about 2000 words +- 250) Introduction 800 words, a mini essay on your topic: - the topic, what you studied: animal, place, reason why this is interesting - the scientific background, what other research exists on this topic, eg other papers - is this original? What have others done? eg other papers What is the theory behind the work? eg other papers You should expect to cite 8 to 10 papers in this section. Materials and Methods (600 words) what animals did you catch (go to genus or family)? How many? Where did you get them? when did you do this? where did you do this? what equipment did you use? where did you get this? what material did you use? where did you get this? what was the experiment? sample size? what analyses did you use? type of data you collected? You should expect to cite 3 to 5 other papers using these methods as justification. 24 Results 250 to 400 words, what you found, with graphs, pictures (figures) and tables, and explanation of these IN THE TEXT. Discussion (500 to 800 words) What did you discover? How does this compare to other studies? How is this relevant to Forensic entomology? What might you do otherwise if you did it again, and what did you learn? You should expect to cite 5 other papers (4 to 10). References OR Literature cited use any format, but be consistent, do not change fonts colours etc. 25 Forensic Entomology David Beresford 2024 26  Lecture content forensically relevant insects: identifying time and place most commonly used for Post Mortem interval of victims of homicides, also used for identification of illicit drugs, other materials ecology of corpses: a corpse is a high nutritional package that is suddenly released into the environment, time and placement is random problem for insects: how to find and colonize these: need separate life history stages with different requirements: immatures (called maggots for flies): to obtain lots of food quickly adults: to find mates, and disperse and find new carcasses adaptive peak of each species based on benefits of generalization vs specialization on food source and generalization vs specialization in environment major problem: availability of food is unpredictable  feast or famine 27 for forensic use: we use insects to identify when and where events occur we use the result of this to gain information: theoretical outline of the process: timeline: death  stages of putrefaction  stages of mummification finding a maggot along this line, we can get its age and work back to determine colonization time flies colonize growth of larvae pupae adults emerge these change indicate age of maggots, and are used to get time since death actual process: not clear demarcations, but distributions 28 however, laying eggs, maggot growth have normal distributions, and there are different sized maggots present over time some come early to lay eggs, some arrive a bit later, some eggs hatch quickly, some slowly, so variability increase with time as the carcass ages 29 the model looks like this, not a sharp change from one stage, but gradual changes with overlap between stages of maggots we use the result of this to gain information: theoretical outline of the process: timeline: death  stages of putrefaction  stages of mummification finding a maggot along this line, we can get its age and work back to determine colonization time flies colonize growth of larvae pupae adults emerge actual process: not clear demarcations, but distributions 30 this becomes more complicated, because it changes with temperature, growth is slow in low temps, fast in high temps we use the result of this to gain information: theoretical outline of the process: timeline: death  stages of putrefaction  stages of mummification finding a maggot along this line, we can get its age and work back to determine colonization time flies colonize growth of larvae pupae adults emerge actual process: not clear demarcations, but distributions 31 sources of variability: intrinsic factors: - early, optimal, late colonizers, distance to other nearest corpse, number of colonizers available, intraspecific competition from other colonizers extrinsic factors: - moisture, sun vs shade, species that arrive, distance to nearest corpse, commonness or rarity of other corpses, predators, parasites, disease - variability associated with the carcass: size of corpse, presence of drugs, food, health of individual, amount of fat vs lean meat (and location of that fat), order of organs colonized, order of utilization, exposure of interior organs and body cavity, access to carcass eg partially submerged? 32 one example of a source of variability colonizers are usually blow flies that deposit eggs if flies get to a corpse first, it is theirs if a burying beetle (also called a Sextant beetle, Order: Coleoptera, family: Silphidae) finds a fresh corpse - competition between beetle and fly maggots both use the corpse BUT if this beetle is carrying predatory mites (Class: Acarina, Family Macrochelidae, Macrocheles muscaedomesticae) - mites eat fly eggs and first instar larvae flies disadvantaged, delayed in colonizing 33 second example of variability, sunlight and shade: WW1: entomologists observed that - sunny portions of the trenches were coated with large bright blue flies the blue bottles (Order Diptera: Family Calliphoridae, Calliphora vicina) - shaded portions of the same trenches coated with medium sized green flies the green bottles (Order Diptera: Family Calliphoridae, Lucillia sp) the sun dries corpses out faster, sunny and shaded habitats are ecologically different 34 Basic Insect structure, hard or tough on outside, soft inside structure of insect cuticle - polysacharide similar to cellulose called chitin, layers stacked to create strong structural membrane - chitin is flexible, not the hard material of the exocuticle which is due to protein called sclerotin - layering also allows aging by counting the cuticular bands, at apodeme between thorax and abdomen - entire insect externally coated with wax (cuticular hydrocarbon) - insect breathes through spiracles or holes connected to tracheal tubes that extend though out body cavity 35 internal structure of the adult muscles: attached to apodemes, or scleritized regions of cuticle require lots of energy, surrounded by trachea contract – power proportional to cross section area – better leveraging system then mammals – muscles are attached to outside structures that allow leveraging to be applied – muscle can be dissolved using KOH, potassium hydroxide, at about 10% concentration – reveal structure of attachment surfaces – can be used to age the insect based on layers cross section of a fly showing muscles (black bands), note lots of muscles in thorax for legs and wings 36  life history of flies (order Diptera) holometabolous, or complete metamorphosis 1 eggs and larval stages differ from adult stage 5 identification based on morphological features (ie the phenotype) X ↓ 4 T flies lay eggs, the eggs become ↳ active (larvae or maggot stage) 2 3 and get nutrition, and go back to being an egg-like stage (the pupae) 37  eggs deposited at various locations, generally in folds, near cavities and openings the mother or female fly choses the best place for her offspring, to be safe and in contact with food 38 immature stages, the maggots immature development divided into three instars or stages moult between each stage immatures to take advantage of large nutritional packages have specialized structures based on habitat maggots can be hairy, covered in setae (bristles) or smooth identified by mouthparts and spiracle head end patterns (breathing tubes) 39 pupae maggots wander from corpse, pupate resemble grains of rice pupae get darker with age adult emerges, rests and dries wings hardens outer cuticle 40 adult flies insects, basic structure: head, thorax, abdomen. flies 2 wings and halters, beetles, hard front wing (you need to know the terms on this page) Y vertical Horizontal - direction Vertical ↓ / direction ) ↑ Horizontal - 41 know the terms on this page - X 42 used for identification to species, but no need to memorize this 43 used for identification to species, but no need to memorize this side view of thorax showing sections and names 44 you only need to know how to use the diagrams, but no need to memorize this pages, gives details typical for identification to species, it is why a picture cannot be used to get species identifications 45 using dichotomous keys, in the next section I give examples of keys, showing some fly structures A key is a decision tree. To use a key, you look to see if your object has the features indicated, and follow the steps Round sides For example, below is a key to shapes. You have a round shape, you use the key, and skip step 2 because the figure has round sides, not straight 1) figure has straight sides …………………………………………….. 2 figure has rounded sides ……………………………………………. 3 8 2 figure has 3 sides ………………………………………………..triangle figure has 4 sides …………………………………………………square3 - 3 figure is as tall as it is wide ………………………………………circle figure is wider than it is tall ………………………………………..ellipse 3 46 An example using a simple Taxonomic identification key (Armed Forces Pest Management Board TECHNICAL GUIDE NO. 30 Armed Forces Pest Management Board Defense Pest Management Information Analysis Center Forest Glen Section/Walter Reed Army Medical Center Washington, DC 20307-5001 Key to Adults of the Non-biting Muscoid Fly Genera 1. Small, usually dark flies; hind tibiae with distinct, curved, shining black, apical or sub-apical spur; third antennal segment globular; arista bare...................................................................................................... Hippelates identity Medium-sized or large flies.................................................................................................... move to 2 2 2. Gray, yellowish, or dull-colored flies........................................................................................ more to 3 3 Blue, metallic green, or blue-green flies................................................................................... move to5 5 47  no bend 3. Bend of fourth vein absent, reaching wing margin far below third vein; arista bare; anal vein characteristically strongly curved forward as if to intersect the sixth Identity Fannia vein..................................................................... Bend of fourth vein acute, joining margin of the wing close to the third vein; arista with hairs..... 4 more to 4 48 4. Frequently large, gray or yellowish colored flies; abdomen with a "checkerboard" appearance; thorax marked with three dark, longitudinal Identity stripes.................................................................................. Sarcophaga Medium-sized grayish-black flies; abdomen without "checkerboard" appearance; thorax marked with two or four dark longitudinal stripes. Musca identity 5. Face yellow with soft yellow pile............................................................... more to 6 6 Face without yellow pile................................................................................. more to 7 7 6. Thorax marked with three longitudinal stripes; lower squama without long hairs above; genus of Western Hemisphere Cochliomyia Identify Thorax without distinct longitudinal stripes; lower squama with long hairs above; confined to Africa and islands of the Pacific, including the Philippines, Australia, and certain sections of Asia....................................... Identity Chrysomya 49 7. Base of first vein with a row of long, distinct hairs on its upper surface; anterior spiracle with bright orange hairs; dark, metallic blue-black in color....................................................................................... Phormia Identity Base of the first vein lacking, or with poorly developed, hairs on its upper surface; anterior spiracle with dark hairs; blue or green in color.................................................................................................... 8 more to 8 8. Usually large flies with a whitish sheen over abdomen; lower squama with long hair above; bluebottle flies Calliphora identity Usually flies of moderate size; lower squama without long hair above; greenbottle flies............................................................................. Phaenicia and Lucilia identity 50 a more detailed and key to forensically important Diptera (for short term PMI assessment) from http://www.nku.edu/~biosci/CoursesNDegree/ForensicFlyKey/species.htm 1a. Basal section of wing vein R with long, thin setae on posterodorsal surface (Fig. 1) more to 2 2 1b. Basal section of wing vein R bare (Fig. 2) more to 3 3 v - 51  2a. Gena yellow or orange, with mostly yellow hair; anterior spiracle pale (Fig. 3) Identity Cochliomyia macellaria 2b. Gena not yellow or orange; anterior spiracle mostly orange yellow (Fig. 4) Identity Phormia regina ~ v 52 3a. Bright curly yellow setae on sides of pleuron (Fig. 5) Pollenia sp. identify 3b. No bright curly yellow setae (Fig. 6) more to 4 4 ↓ V 53 4a. Lower calypter haired (Fig. 7); wing vein R5 ventrally bare beyond node (Fig. 8); thorax dull, pruinose (Fig. 9); abdomen shining, usually metallic blue (Fig. 10) move to 5 5 4b. Lower calypter bare (Fig. 11); wing vein R5 ventrally haired beyond node (Fig. 12); thorax and abdomen both shining, usually metallic green (Fig.13 & 14) 6 more to 6 smalehairs 54 55 5a. Bucca reddish on anterior half or more (Fig. 15); basicosta yellow to yellow orange (Fig. 16) identity Calliphora vicina 5b. Bucca entirely black (Fig. 17) ; basicosta black (Fig. 18) Calliphora vomitoria identity 56 6a. Subcostal sclerite with conspicuous black hairs on apical half of ventral base of wing (Fig. 19) identity Lucilia illustris 6b. Subcostal sclerite with micropubescence only on apical half more to 7 of ventral base of wing (Fig. 20) 7 57 7a. Basicosta black (Fig. 21), Palpus brown (darker at tip) (Fig. 22) Bufolucilia silvarum 7b. Basicosta pale (Fig. 23); Palpus orange yellow (Fig. 24) more 68 8 58 8a. Two pairs of postacrostichal bristles (Fig. 25) Phaenicia coeruleiviridis identity 8b. Three pairs of postacrostichal bristles (Fig. 26) Phaenicia sericata Identity 59  Phormia regina Pollenia sp. Calliphora vicina Calliphora vomitoria Lucilia illustris Bufolucilia silvarum 60 Phaenicia coeruleiviridis Phaenicia sericata Cochliomyia macellaria