The Science of Forensic Entomology

David B Rivers Loyola University Maryland, Maryland, USA Gregory Dahlem Northern Kentucky University, Kentucky, USA

About the companion website xii Preface xiii Chapter 1 Role of forensic science in criminal investigations 1 Overview 1 The big picture 1 1.1 What is forensic science? 1 1.2 Application of science to criminal investigations 3 1.3 Recognized specialty disciplines in forensic science 9 Chapter review 10 Test your understanding 11 Notes 12 References cited 12 Supplemental reading 12 Additional resources 12 Chapter 2 History of forensic entomology 13 Overview 13 The big picture 13 2.1 Historical records of early human civilizations suggest understanding of insect biology and ecology 13 2.2 Early influences leading to forensic entomology 16 2.3 Foundation for discipline is laid through casework, research, war, and public policy 18 2.4 Turn of the twentieth century brings advances in understanding of necrophagous insects 21 2.5 Forensic entomology during the great wars 22 2.6 Growth of the discipline due to the pioneering efforts of modern forensic entomologists leads to acceptance by judicial systems and public 23 Chapter review 24 Test your understanding 26 Notes 26 References cited 26 Supplemental reading 27 Additional resources 27 Chapter 3 Role of insects and other arthropods in urban and stored product entomology 29 Overview 29 The big picture 29 3.1 Insects and other arthropods are used in civil, criminal, and administrative matters pertinent to the judicial system 29 3.2 Civil cases involve disputes over private issues 31 3.3 Criminal law involves more serious matters involving safety and welfare of people 31 3.4 Administrative law is concerned with rulemaking, adjudication, or enforcement of specific regulatory agendas 32 3.5 Stored product entomology addresses issues of both a civil and criminal nature 33 3.6 Urban entomology is focused on more than just urban issues 38 Chapter review 42 Test your understanding 44 Notes 45 References cited 45 Supplemental reading 46 Additional resources 46 Chapter 4 Introduction to entomology 47 Overview 47 The big picture 47 4.1 Insecta is the biggest class of the biggest phylum of living organisms, the Arthropoda 47 4.2 The typical adult insect has three body parts, six legs, two antennae, compound eyes, external mouthparts, and wings 50 4.3 Tagmosis has produced the three functional body segments of insects: the head, thorax, and abdomen 51 4.4 Sensory organs and their modifications allow insects to perceive and react to their environments 55 4.5 The structure and function of an insect s digestive system is intimately tied to the food that it prefers to eat 57 4.6 A tubular tracheal system transports oxygen to the body s cells while blood moves through the body without the aid of a vascular system 58 4.7 The nervous system of insects integrates sensory input and drives many aspects of behavior 60 4.8 In order to grow, insects need to shed their skin 61 4.9 Many insects look and behave entirely differently as a larva than as an adult the magic of metamorphosis 61 4.10 The desire to reproduce is a driving force for unique reproductive behaviors and copulatory structures in insects 62 Chapter review 64 Test your understanding 65 References cited 66 Supplemental reading 67 Additional resources 67 Chapter 5 Biology, taxonomy, and natural history of forensically important insects 69 Overview 69 The big picture 69 5.1 A variety of different insects and terrestrial arthropods are attracted to a dead body 69 5.2 The fauna of insects feeding on a body is determined by location, time, and associated organisms 71 5.3 Necrophagous insects include the taxa feeding on the corpse itself 72 5.4 Parasitoids and predators are the second most significant group of carrion-frequenting taxa 85 5.5 Omnivorous species include taxa which feed on both the corpse and associated arthropods 87 5.6 Adventitious species include taxa that use the corpse as an extension of their own natural habitat 89 Chapter review 90 Test your understanding 92 References cited 92 Supplemental reading 94 Additional resources 94 Chapter 6 Reproductive strategies of necrophagous flies 95 Overview 95 The big picture 95 6.1 The need to feed: anautogeny and income breeders are common among necrophagous Diptera 95 6.2 Size matters in egg production 98 6.3 Progeny deposition is a matter of competition 100 6.4 Larvae are adapted for feeding and competing on carrion 102 6.5 Feeding aggregations maximize utilization of food source 103 6.6 Mother versus offspring: fitness conflicts 104 6.7 Resource partitioning is the path to reproductive success 105 Chapter review 106 Test your understanding 108 Notes 109 References cited 109 Supplemental reading 111 Additional resources 112 Chapter 7 Chemical attraction and communication 113 Overview 113 The big picture 113 7.1 Insects rely on chemicals in intraspecific and interspecific communication 113 7.2 Chemical communication requires efficient chemoreception 114 7.3 Semiochemicals modify the behavior of the receiver 115 7.4 Pheromones are used to communicate with members of the same species 116 7.5 Allelochemicals promote communication across taxa 118 7.6 Chemical attraction to carrion 120 7.7 Chemical attraction to carrion by subsequent fauna 122 Chapter review 124 Test your understanding 127 Notes 127 References cited 127 Supplemental reading 129 Additional resources 130 Chapter 8 Biology of the maggot mass 131 Overview 131 The big picture 131 8.1 Carrion communities are composed largely of fly larvae living in aggregations 131 8.2 Formation of maggot masses involves clustering during oviposition or larviposition 132 8.3 Larval feeding aggregations provide adaptive benefits to individuals 134 8.4 Developing in maggot masses is not always beneficial to conspecifics or allospecifics 140 Chapter review 143 Test your understanding 145 References cited 146 Supplemental reading 149 Additional resources 149 Chapter 9 Temperature tolerances of necrophagous flies 151 Overview 151 The big picture 151 9.1 Necrophagous insects face seasonal, aseasonal, and self-induced (heterothermy) temperature extremes 152 9.2 Temperature challenges do not equal death: necrophagous insects are equipped with adaptations to survive a changing environment 153 9.3 Life-history features that promote survival during proteotaxic stress 154 9.4 Deleterious effects of high temperatures on necrophagous flies 158 9.5 Life-history strategies and adaptations that promote survival at low temperatures 160 9.6 Deleterious effects of low-temperature exposure 166 Chapter review 167 Test your understanding 170 Notes 171 References cited 171 Supplemental reading 174 Additional resources 174 Chapter 10 Postmortem decomposition of human remains and vertebrate carrion 175 Overview 175 The big picture 175 10.1 Decomposition of human and other vertebrate remains is a complex process 175 10.2 Numerous factors affect the rate of body decomposition 177 10.3 When the heart stops: changes occur almost immediately but are not outwardly detectable 179 10.4 Body decomposition is characterized by stages of physical decay 184 Chapter review 187 Test your understanding 190 Notes 190 References cited 190 Supplemental reading 192 Additional resources 192 Chapter 11 Insect succession on carrion under natural and artificial conditions 193 Overview 193 The big picture 193 11.1 What s normal about terrestrial decomposition? Typical patterns of insect succession on bodies above ground 194 11.2 Succession patterns under forensic conditions are not typical 196 11.3 Several factors serve as barriers to oviposition by necrophagous insects 198 11.4 The physical conditions of carrion decay can function as a hurdle to insect development 200 11.5 Insect faunal colonization of animal remains is influenced by conditions of physical decomposition 204 Chapter review 208 Test your understanding 211 Notes 211 References cited 212 Supplemental reading 214 Additional resources 214 Chapter 12 Postmortem interval 215 Overview 215 The big picture 215 12.1 The time since death is referred to as the postmortem interval 215 12.2 The role of insects in estimating the PMI 217 12.3 Modeling growth temperature relationships 220 12.4 Calculating the PMI requires experimental data on insect development and information from the crime scene 222 12.5 The evolving PMI: changing approaches and sources of error 227 Chapter review 230 Test your understanding 232 Notes 233 References cited 233 Supplemental reading 235 Additional resources 235 Chapter 13 Insect alterations of bloodstain evidence 237 Overview 237 The big picture 237 13.1 Bloodstains are not always what they appear to be at the crime scene 237 13.2 Science is the cornerstone of bloodstain pattern analyses 238 13.3 Crash course in bloodstain analyses 240 13.4 Insect activity can alter blood evidence 243 13.5 Insect feeding activity on bloodstains or fresh blood can yield regurgitate spots or transference 243 13.6 Digested blood is eliminated from insects as liquid feces or frass 245 13.7 Parasitic insects can confound blood evidence by leaving spot artifacts 246 Chapter review 246 Test your understanding 248 Notes 248 References cited 249 Supplemental reading 249 Additional resources 250 Chapter 14 Necrophagous and parasitic flies as indicators of neglect and abuse 251 Overview 251 The big picture 251 14.1 Parasitic and necrophagous flies can infest humans, pets, and livestock 252 14.2 Not all forensically important insects wait until death to feed 253 14.3 Chemoattraction of flies to the living does not necessarily differ from the odors of death 255 14.4 Necrophagous and parasitic flies display oviposition and development preferences on their vertebrate hosts 257 14.5 Larval myiasis can be fatal 258 Chapter review 261 Test your understanding 263 Notes 263 References cited 264 Supplemental reading 265 Additional resources 266 Chapter 15 Application of molecular methods to forensic entomology 267 Overview 267 The big picture 267 15.1 Molecular methods: living things can be defined by their DNA 267 15.2 Evidence collection: preserve DNA integrity 270 15.3 Molecular methods of species identification 270 15.4 DNA barcoding protocol 275 15.5 Problems encountered in barcoding projects 279 15.6 Gut content: victim and suspect identifications 280 15.7 Molecular methods and population genetics 281 15.8 Molecular methods: non-DNA based 282 15.9 Validating molecular methods for use as evidence 284 15.10 Future directions 284 Chapter review 285 Test your understanding 287 References cited 288 Supplemental reading 291 Additional resources 292 Chapter 16 Archaeoentomology: insects and archaeology 293 Overview 293 The big picture 293 16.1 Archaeoentomology is a new old discipline 293 16.2 Concepts and techniques from forensic entomology can be applied to archaeology 295 16.3 Ancient insects and food: connection to stored product entomology 296 16.4 Ancient insects as pests: beginnings of synanthropy and urban entomology 298 16.5 Ancient insects and mummies: revelations about past lives and civilizations 301 16.6 Forensic archaeoentomology: entomological investigations into extremely cold cases 304 Chapter review 304 Test your understanding 306 Notes 307 References cited 307 Supplemental reading 309 Additional resources 309 Chapter 17 Insects as weapons of war and threats to national security 311 Overview 311 The big picture 311 17.1 Terrorism and biological threats to national security are part of today s world 312 17.2 Entomological weapons are not new ideas 314 17.3 Direct entomological threats to human populations are not all historical 316 17.4 Impending entomological threats to agriculture and food safety 318 17.5 Insect-borne diseases as new or renewed threats to human health 319 17.6 Insects can be used as tools for national security 321 Chapter review 324 Test your understanding 327 Notes 328 References cited 328 Supplemental reading 329 Additional resources 329 Chapter 18 Deadly insects 331 Overview 331 The big picture 331 18.1 Insects that bite, sting or secrete cause fear, loathing, and death 332 18.2 Insects that cause death 333 18.3 Human envenomation and intoxication by insect-derived toxins 338 18.4 Insects that injure humans rely on chemically diverse venoms and toxins 338 18.5 Non-insect arthropods that should scare you! 342 18.6 Implications of deadly insects for forensic entomology 345 Chapter review 346 Test your understanding 349 Notes 349 References cited 350 Supplemental reading 351 Additional resources 351 Appendix I Collection and preservation of calyptrate Diptera 353 Collecting adult flies 353 Collecting fly larvae 355 Mounting and preserving specimens (adult flies) 355 References cited 357 Resources and links 357 Appendix II Getting specimens identified 359 Morphological identification of specimens on your own 359 Identification of specimens (by systematic expert) 360 References cited 361 Resources and links 361 Appendix III Necrophagous fly life table references 363 Glossary 367 Index 377