Exploiting Insect Olfaction in Forensic Entomology

11.1 Introduction

Insects, specifically blowflies (Diptera: Calliphoridae), are often the first to arrive at the scene of a crime and provide crucial information including post mortem interval and whether the body has been moved from its original location, amongst other useful information. History tells us that insects' association with death was recognised as early as documentation of events could be made (Greenberg and Kunich 2005; Benecke 2001). As we continue to understand this link dramatic advances, such as those mentioned throughout this book, are continually being made in the field of Forensic Entomology in relation to different situations, environments, as well as the incorporation of new approaches. While the methods used to determine the postmortem interval (PMI), such as larval age determination and arthropod succession, are continually being used and further investigated the mechanism which attracts the flies to the body has not been fully explored. It is well documented that female flies will lay eggs near wounds or natural orifices soon after death so that the larvae may develop in a moist area (Smith 1986; Anderson 2001). However, determining exactly what attracts insects to a decomposing body and cause behavioural responses such as mating and laying eggs (oviposition), has still not been identified.

As humans, we primarily sense our world using vision, sound and touch (Cadré and Millar 2004). It is therefore understandable that we, at times, underestimate the importance of olfaction, the sense of smell. Insects perceive the world differently to humans and their ecology relies, sometimes almost exclusively, on chemicals they detect from their environment. Carrion insects are no exception to this.

It has been widely accepted that female carrion flies are attracted to volatile chemical cues emitted by a decomposing body (their host) in order to establish a

H.N. LeBlanc

Faculty of Science, University of Ontario Institute of Technology, Oshawa, Canada J.G. Logan

Biological Chemistry Department Hertfordshire, Centre for Sustainable Pest and Disease Management, UK

J. Amendt et al. (eds.), Current Concepts in Forensic Entomology, 205

DOI 10.1007/978-1-4020-9684-6_11, © Springer Science + Business Media B.V. 2010

suitable site for oviposition (Ignell and Hansson 2005). Although we know that body-derived odours are likely to attract the carrion insect to the body, we have not yet identified the chemicals responsible for the attraction and whether the chemicals covey additional information to the insects. The aim of this chapter is to describe recent advances in forensic entomology research and state-of-the-art techniques used to investigate insect responses to volatile chemicals from a decomposing body. The identification of such chemicals could aid in the development of new tools to estimate a more accurate PMI.

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