Faunal Succession of Necrophilous Insects Associated with High-Pofile Wildlife Carcasses in Louisiana
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Louisiana State University LSU Digital Commons LSU Doctoral Dissertations Graduate School 2004 Faunal succession of necrophilous insects associated with high-pofile wildlife carcasses in Louisiana Erin Jean Grindley Watson Louisiana State University and Agricultural and Mechanical College, [email protected] Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_dissertations Part of the Entomology Commons Recommended Citation Watson, Erin Jean Grindley, "Faunal succession of necrophilous insects associated with high-pofile wildlife carcasses in Louisiana" (2004). LSU Doctoral Dissertations. 3235. https://digitalcommons.lsu.edu/gradschool_dissertations/3235 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Doctoral Dissertations by an authorized graduate school editor of LSU Digital Commons. For more information, please [email protected]. FAUNAL SUCCESSION OF NECROPHILOUS INSECTS ASSOCIATED WITH HIGH-PROFILE WILDLIFE CARCASSES IN LOUISIANA A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of Doctor of Philosophy in The Department of Entomology by Erin Jean Grindley Watson B.A. Western Washington University, 1997 August 2004 IN MEMORY This dissertation is dedicated to the three most influential people in my life and graduate career, may their memory live on through me. To my original advisor, C. Lamar Meek, whose enthusiasm for forensic entomology was contagious. To my husband, Rob, you had and always will have a profound impact on my life. And to my father, I will always be proud to say that I am my father’s daughter. ii ACKNOWLEDGEMENTS I express sincere appreciation to the Louisiana State University Agricultural Center, the Department of Entomology, and the Louisiana Department of Wildlife and Fisheries. I would like to thank my major advisor, Dr. Chris Carlton, my previous advisor, Dr. C. Lamar Meek, as well as graduate committee members Drs. Lane Foil, Seth Johnson, Dorothy Prowell, Charles Ramcharan, and Mary Manhein. I would also like to express gratitude to the former department head Dr. Frank Guillot, former interim head Dr. James Fuxa, and current department head Dr. Timothy Schowalter. A special thank you is given to Dr. Jay Geaghan of the Department of Experimental Statistics for assistance with statistical analyses. His expertise and dedication to this project were invaluable. I would also like to acknowledge my undergraduate advisor, Dr. Joan C. Stevenson, of the Anthropology Department at Western Washington University, for introducing me to the field of forensic entomology. Taxonomic identifications provided by the following persons are also greatly appreciated: Alexey Tishechkin (Histeridae), Andrew Cline (Nitidulidae), Steve Marshall (Sphaeroceridae), Gary Gibson (Mymaridae, Pteromalidae), and Lubomir Masner (Ceraphronidae, Diapriidae, Megaspilidae, Platygastridae, Scelionidae). Lastly, I would like to thank my family and friends for their support and encouragement throughout my graduate tenure. This project was supported in part by the Louisiana Department of Wildlife and Fisheries. iii TABLE OF CONTENTS ACKNOWLEDGEMENTS…....…………………………………………………….... iii ABSTRACT……………...………………………………………………………….... vi CHAPTER 1. BACKGROUND AND PROJECT OVERVIEW………...………..... 1 Introduction………………………………………………...………... 1 Role of Blow Flies in Decompositon………………………...…….... 2 Five Stages of Decomposition………………………………...….…. 3 Carrion Trophic Interactions……………………………………....… 5 Early Influences of Carrion Ecology on Forensic Entomology……... 6 Forensic Entomology………………………………………………... 7 Louisiana Necrophilous Diptera……………………………...……... 9 Hairy Maggot Blow Fly………………………………………...…… 10 Postmortem Interval Estimation of Wildlife…………………....…… 11 Louisiana Black Bear………………………………………...…….... 12 American Alligator……………………………………………...…... 13 White-tailed Deer…………………...………………………...…….. 14 Poaching of Louisiana Wildlife…...……………………..……….…. 15 Rationale for Research…...………………………...……………….. 17 Research Objectives…...……………………………...………….…. 17 Methodology………...……………………………...…………..…… 18 References Cited…...……………………………...………………… 22 2. SPRING SUCCESSION OF NECROPHILOUS INSECTS ON WILDLIFE CARCASSES IN LOUISIANA………………………… 28 Introduction………………………………………………………….. 28 Materials and Methods………………………………………………. 29 Results……………………………………………………………….. 34 Discussion…………………………………………………………… 44 References Cited…………………………………………………….. 49 3. FALL AND WINTER SUCCESSION OF NECROPHILOUS INSECTS ON WILDLIFE CARCASSES IN LOUISIANA……….. 52 Introduction…………………………………………………………. 52 Materials and Methods……………………………………………… 52 Results………………………………………………………………. 55 Discussion……...………...……………..…………………………... 72 References Cited……………………………………………………. 82 4. QUANTITATIVE ASSESSMENT OF NECROPHILOUS COMMUNITIES ASSOCIATED WITH WILDLIFE CARCASSES USING PITFALL TRAP DATA……………….…… 86 iv Introduction…………..………………………………………….… 86 Materials and Methods…………………………………………….. 87 Results…………………………………………………………...… 90 Discussion…………………………………………………………. 108 References Cited…………………………………………………... 117 5. SUCCESSION OF FORENSICALLY IMPORTANT SILPHID LARVAE ON LARGE CARCASSES (COLEOPTERA: SILPHIDAE)………………………………………..……………… 119 Introduction………………………………………………………… 119 Materials and Methods……………………………………….…….. 121 Results………………………………………………………...……. 123 Discussion………………………………………………………….. 127 References Cited…………………………………………………… 132 6. CONCLUSION……………………..……………...………………. 134 APPENDIX A. CHECKLIST OF TAXA………………..…………………………. 139 B. LETTER OF PERMISSION………………………………………. 149 C. REFINED DATASET (167 TAXA)……………………………..... 151 D. FREQUENCY DATA BY STAGE OF DECOMPOSITON……… 156 E. FREQUENCY DATA BY SEASON AND ANIMAL TYPE…..… 167 F. SELECTED DIVERSITY DATA…………………………………. 177 G. SELECTED PRINCIPLE COMPONENT ANALYSIS DATA…... 181 H. SELECTED DISCRIMINANT ANALYSES DATA…………...… 186 I. MORPHOMETRIC SILPHID BEETLE DATA……….….……… 201 VITA……………………………………………………………………………….. 212 v ABSTRACT The same entomological criteria used in estimating time of death for humans are applicable for deceased wildlife. Necrophilous insects associated with animal carcasses can provide wildlife law enforcement with valuable information necessary for postmortem interval estimation, and ultimately, to incriminate poachers. The purpose of this research was twofold: to establish species composition, faunal succession patterns, and species and life stage interactions of necrophilous insects associated with three wildlife species; and to identify new methods of evaluating succession patterns using statistical measures. Twenty-one large vertebrate carcasses were monitored throughout decomposition in a mixed flatwood forest in East Baton Rouge Parish, LA during the spring and fall of 1999, and winter of 2000. Each seasonal experiment included one Louisiana black bear (a threatened species), two white-tailed deer, two American alligators, and two swine (experimental standard). Fresh carcasses were sampled simultaneously for necrophilous arthropods manually and by pitfall traps. Manual sampling contributed qualitative observational data regarding decomposition patterns and species interactions not easily revealed using pitfall traps alone and represented typical entomological collections recovered during criminal investigations. Principle component analysis reduced the complete pitfall trap dataset (451,036 specimens representing 438 taxa) to a statistically manageable size, and regression analysis (Proc Mixed, SAS Institute) determined that season, animal type, and stage of decomposition were significant for species composition. Three discriminant analyses determined which taxa were most discriminating for animal type: Proc StepDisc identified 50 taxa, Proc Discrim determined that these taxa were more discriminating for alligator, and Proc CanDisc identified species assemblages per animal type and illustrated that alligator and bear were more unique than deer vi and swine carrion. Canonical correlation analysis (Proc CanCorr) tested daily time trends in arthropod activity in relation to days of decomposition. Two diversity tests were conducted for these data, Shannon’s diversity index and Pielou’s J test of species evenness. Season was significant for both species diversity and evenness, while stage of decomposition was significant for only Pielou’s J, and animal type was never significant. Results from this project further our understanding of the carrion habitat and provide baseline data to wildlife law enforcement agencies for prosecuting poachers. vii CHAPTER 1 BACKGROUND AND PROJECT OVERVIEW Introduction The development of the field of Forensic Entomology has proven to be a tremendous asset in forensic investigation. As living matter, necrophilous (i.e., carrion- frequenting) insects provide a new and relatively unexplored medium for forensic science. Particularly within the last two decades, the incorporation of entomological research has become extremely valuable in determining the postmortem interval (PMI) of homicides, suicides, and other unattended deaths. The same entomological criteria used to estimate time of death of humans are also applicable for determining PMI of suspicious deaths of wildlife species, and ultimately, to incriminate poachers. Decomposing remains provide a food source for necrophilous arthropods, and hence, a unique and self-contained habitat. A fresh corpse or animal carcass functions