The study was conducted on the forensic entomotoxicological evaluation of carrion insects from domestic fowls euthanized with dichlorvos (sniper) insecticide. The research centers on the collection and analysis of insects on the carrions and the impact of the insecticide on them.
It entailed a forensic entomotoxicological evaluation between October and December 2019. The fowls for the study were procured from the main campus of the University of Ibadan. They were then euthanized using 3ml and 5ml of dichlorvos. The adult carrion insects were collected using a sweep net and stored in silica gel. Larvae and pupae were also collected and stored in sample bottles containing 70% ethanol. The temperatures of the environment and the carcasses were measured using an infrared thermometer, while the relative humidity was recorded from a digital hygrometer. The fly families Calliphoridae and Muscidae were the initial colonizers of the decomposing carcass, while Sarcophagidae arrived shortly after the fresh stage of decomposition.
Table of Contents
CHAPTER ONE
INTRODUCTION
CARRION INSECTS
DICHLORVOS
Aim and Objective of the Study
CHAPTER TWO
LITERATURE REVIEW
2.0 Introduction
2.1 Urban forensic entomology
2.2 Stored-product forensic entomology
2.3 Medico-legal forensic entomology
2.4 Carrion Insect
2.5 Insect Succession
2.6 Factors affecting fly development
2.6.1 Temperature
2.6.2 Habitat Influence
2.7 Types of carrion insect and Arthropods
2.7.1 Calliphoridae
2.7.2 Sarcophagidae
2.7.3 Muscidae
2.7.4 Piophilidae
2.7.5 Silphidae
2.7.6 Cleridae
2.7.7 Dermestidae
2.8 Dichlorvos (Sniper)
2.8.1 Sniper mode of action
2.9 Review of Previous Literatures
CHAPTER THREE
MATERIALS AND METHOD
3.1 Study Site
3.2.1 Sample Collection and Processing
3.2.2 Preparation of Domestic Fowl for Set-up
3.2.3 Mounting the Fowls
3.2.4 Sampling of carrion insect stages
3.2.4.2 Sampling for maggot
3.3 Measurement of larval body length and weight
3.4 Measurement of carcass temperature and humidity
CHAPTER FOUR
RESULTS
4.1 Abundance and species composition of carrion insects on domestic fowl carcass
4.2 Carrion insect succession on domestic fowl carcass
4.3 Effect of dichlorvos on the length and weight of Chrysomya albiceps larva
4.4 Variations in environmental variables at the field site
PICTURES OF CARRION DECOMPOSITION IN THE STUDY
CHAPTER FIVE
DISCUSSION
5.1 Abundance and specie composition of carrion insects on domestic fowl carcass
5.2 Carrion insect succession on domestic fowl carcass
5.3 Effect of dichlorvos and feather on the length and weight of larva
5.4 Variations in environmental variables at the field site
5.5 CONCLUSION
Research Objectives & Scope
This study investigates the forensic entomotoxicological impact of the insecticide Dichlorvos (Sniper) on the decomposition process and the succession patterns of carrion insects using domestic fowl carcasses as animal models. By manipulating feather presence and toxin dosage, the research aims to provide data that can help estimate post-mortem intervals and assist in forensic suicide investigations.
- Impact of toxicological substances on insect larval growth and development.
- Evaluation of carrion insect diversity and abundance under chemical influence.
- Analysis of insect succession patterns on decomposing remains.
- Influence of experimental environment (temperature/moisture) on decomposition rates.
Excerpt from the Book
CARRION INSECTS
Carrion insects are the insects associated with the decomposition of the remains. The decomposition process begins within a few minutes of death (Vass et al, 2002). Decomposing remains provide a temporary, evolving site of concentrated resources that are used by a wide range of species, frequently the first to arrive are arthropods and the predominant exploitative community. Not all arthropods found on or nearby decomposing remains will play an active role in the process of decay (Goff, 1993).
Carrion insects are commonly described based on their ecological role (Smith, 1986). Four commonly described roles are: 1. Necrophagous species 2. Predators and parasites of necrophagous species 3. Omnivorous species 4. Adventive species
Necrophagous animals are insects / arthropods that feed directly on remains, or fluids that are released during the process of decomposition (Goff, 1993).
Summary of Chapters
CHAPTER ONE: Provides an introduction to the field of forensic entomotoxicology and discusses its significance in solving suicide cases involving pesticide ingestion.
CHAPTER TWO: Reviews existing literature on forensic entomology, including insect succession stages and the specific roles of various insect families, as well as the properties of Dichlorvos.
CHAPTER THREE: Details the materials and methods used for the study, including specimen collection, site selection, and the experimental protocol for poisoning and monitoring the carcasses.
CHAPTER FOUR: Presents the recorded data, including abundance of insect species at different decomposition stages and the impact of the toxicant on larval development.
CHAPTER FIVE: Discusses the experimental findings, offering conclusions on how poisoning and physical coverings like feathers influence the decomposition process and forensic evidence accuracy.
Keywords
Entomotoxicology, Dichlorvos, Domestic fowl, Calliphoridae, Decomposition, Forensic Science, Insect Succession, Larval Development, Post-mortem Interval, Pesticide, Carrion Insects, Sarcophagidae.
Frequently Asked Questions
What is the core focus of this scientific research?
The research focuses on forensic entomotoxicology, examining how Dichlorvos, an insecticide, affects the succession of carrion insects and the growth of larvae on decomposing remains to aid in forensic death investigations.
What are the primary themes addressed in the study?
The main themes include insect succession patterns, the impact of organophosphate toxicity on decomposition, the influence of physical barriers (feathers) on insect colonization, and the use of environmental variables to estimate time of death.
What is the main objective of this study?
The primary aim is to assess the effects of a specific pesticide (Sniper/Dichlorvos) on carrion insect abundance, diversity, and developmental rates to better inform forensic estimation of post-mortem intervals.
Which scientific methodology was utilized?
The methodology involved euthanizing domestic fowls with specific doses of Dichlorvos, placing them in a field environment, and conducting longitudinal sampling of adult insects, larvae, and pupae, alongside temperature and humidity measurements.
What topics are covered in the main body of the work?
The main body covers the theoretical background of forensic entomology, detailed experimental site criteria, step-by-step procedures for sampling different insect stages, and a comprehensive analysis of field results.
Which keywords characterize this work?
Key terms include Entomotoxicology, Dichlorvos, Decomposition, Calliphoridae, forensic science, and Post-mortem interval.
How does the presence of feathers affect the study results?
The study found that feathers act similarly to clothing on a human body; their presence delays insect colonization and alters the decomposition rate compared to defeathered carcasses.
How does Dichlorvos influence larval growth?
The data indicates that Dichlorvos has a retarding effect on the growth and weight of larvae, specifically in Chrysomya albiceps, compared to less poisoned or baseline environments.
- Quote paper
- Emmanuel Tyokumbur (Author), 2023, Forensic Entomotoxicology. A Study on the Impact of Dichlorvos on Carrion Insects in Domestic Fowls, Munich, GRIN Verlag, https://www.grin.com/document/1378517
