Graduate Theses, Dissertations, and Problem Reports 2014 The Development of an Insect Succession Model Suitable for Time-Since-Death Statistics Anne E. Perez Follow this and additional works at: https://researchrepository.wvu.edu/etd Recommended Citation Perez, Anne E., "The Development of an Insect Succession Model Suitable for Time-Since-Death Statistics" (2014). Graduate Theses, Dissertations, and Problem Reports. 7339. https://researchrepository.wvu.edu/etd/7339 This Dissertation is protected by copyright and/or related rights. It has been brought to you by the The Research Repository @ WVU with permission from the rights-holder(s). You are free to use this Dissertation in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you must obtain permission from the rights-holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/ or on the work itself. This Dissertation has been accepted for inclusion in WVU Graduate Theses, Dissertations, and Problem Reports collection by an authorized administrator of The Research Repository @ WVU. For more information, please contact [email protected]. The Development of an Insect Succession Model Suitable for Time- Since-Death Statistics Anne E. Perez Dissertation submitted to the Eberly College of Arts and Sciences at West Virginia University in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Biology Jeffrey D. Wells, Ph.D., Chair Rita V. M. Rio, Ph. D., Chair of Record Kevin C. Daly, Ph. D. Lynn R. LaMotte, Ph.D. Keith B. Morris, Ph.D. Department of Biology Morgantown, West Virginia 2014 Keywords: forensic entomology, succession interval, postmortem interval, intercarcass distance, accumulated degree hours, statistics Copyright 2014 Anne E. Perez UMI Number: 3618314 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. UMI 3618314 Published by ProQuest LLC (2014). Copyright in the Dissertation held by the Author. Microform Edition © ProQuest LLC. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, MI 48106 - 1346 ABSTRACT The Development of an Insect Succession Model Suitable for Time-Since-Death Statistics Anne E. Perez For academic carrion insect succession studies to be applicable to forensic casework, the study must provide statistically defensible postmortem interval (PMI) estimates. Multiple statistical approaches have been used to describe insect succession, but no study to date has been able to determine a confidence interval about a succession based PMI estimate. The ability to reject PMI values, and thereby create a confidence interval is determined by statistical power, of which sample size is a positive correlate. A proposed model established prospective sample sizes for desired levels of statistical power, indicating a target sample size of ~50 carcasses for estimating PMI based on two carrion insect species (LaMotte and Wells 2000). A surrogate for human decomposition has been identified, the domestic pig, yet studies to date have failed to include more than 5 carcasses in a single treatment group. This lack of replication has lead to strictly observational findings that are unsuitable for forensic use. As replication of carcasses increases, in an attempt to generate a suitable reference insect succession dataset, additional obstacles are encountered. Constraints of time and space, as well as development of an appropriate species list and sampling procedure are of specific concern. Throughout a century of research concerning insect succession on carrion, issues central to development of large datatsets, including the effect of year, fine-scale spatial discrepancies, repeated sampling and intercarcass distance, remain largely unknown. The use of temperature to describe succession is an additional area of succession research critical to casework application. Because temperature directly affects decomposition rates, insect development rates and insect activity, succession data collected across time and space (potentially experiencing differing temperature histories) may most accurately be described using a physiological time measure as compared to an absolute time measure. Further, succession described in physiological time may be more accurate for application to a case that occurred at a different time and location than the reference dataset. The proposed research aims to create a succession dataset that is suitable for statistical analysis and estimation of time since death by: (1) investigating current sampling methods as well as the assumption that succession is consistent among year and small-scale variation in location, (2) determination of minimum intercarcass distance to ensure independence of carcasses, (3) identifying candidate insect species appropriate for analytical methods prescribed by LaMotte and Wells (2000), and (4) assessing accuracy of PMI estimates using an absolute and physiological time measure. Acknowledgements I would first like to thank my doctoral advisor, Jeffrey Wells, Ph.D. Leading by example, he inspires true passion and fearless defense of your science. I would also like to thank my committee members, Rita, Kevin, Keith, and Lynn for their thoughtful comments and support throughout my graduate carreer. I need to thank two additional mentors Neal Haskell, Ph.D., and Ken Schoenly, Ph.D. Without Neal, a study of this magnitude would not have been possible. He generously offered up his land, home, time and expertise to a very green graduate student. Ken was an extremely gracious resource for semivariogram analyses. I am grateful to current and former Wells’ lab members, Christine, Baneshwar, Lizmery, Miriam and Josh, as well as former fellow graduate students Stephanie, Sarah and John. A positive peer- based souding board is a necessity of graduate student life. Additionally I would like to thank the Biology Department staff: Mickey, Diana, Judy, Pat and Wendy. Each of these people, at one time or another, put a smile on my face and made my life a little easier. Thanks to my husband Louie for embracing forensic entomology and tolerating the smell. iii Table of Contents ABSTRACT ................................................................................................................................... ii ACKNOWLEDGEMENTS ........................................................................................................ iii LIST OF FIGURES ..................................................................................................................... vi LIST OF TABLES ...................................................................................................................... vii CHAPTER 1: General Introduction ............................................................................................1 References ..........................................................................................................................14 CHAPTER 2: Spatio-temporal and Sampling Effects on Carrion Insect Communities: Considerations for Generating Large Forensic Datasets Abstract ..............................................................................................................................27 Introduction .......................................................................................................................28 Materials and Methods .......................................................................................................31 Results and Discussion ......................................................................................................34 References ..........................................................................................................................38 CHAPTER 3: Toward the Determination of Minimum Intercarcass Distance for Forensic Entomology Field Methodologies Abstract ..............................................................................................................................51 Introduction .......................................................................................................................51 Materials and Methods .......................................................................................................56 Results and Discussion ......................................................................................................59 References ..........................................................................................................................61 CHAPTER 4: Evaluating the Utility of Hexapod Species for Calculating a Confidence Interval about a Succession Based Postmortem Interval Estimate Abstract ..............................................................................................................................76 Introduction .......................................................................................................................77 Materials and Methods .......................................................................................................80 Results and Discussion ......................................................................................................81