Research 1621 Insect Succession

Insects colonize a corpse in a predictable sequence, therefore the set of species occurring on a corpse, both present and absent may indicate PMI (e.g. Hewadikaram and Goff 1991; Anderson 2001; Grassberger and Frank 2004; Tabor et al. 2004; De Jong and Hoback 2006). The results of the quoted papers are often site- and season-specific, even dealing with a more or less identical insect fauna. Factors that appear to influence succession pattern include the

Institute of Forensic Medicine, Frankfurt am Main, Germany D.G. Johnson and J. Wells

Department of Biology, West Virginia University, Morgantown, USA

J. Amendt et al. (eds.), Current Concepts in Forensic Entomology, 353

DOI 10.1007/978-1-4020-9684-6_16, © Springer Science + Business Media B.V. 2010

illumination of the scene, size of the cadaver, time of the year, and type of habitat (Amendt et al. 2004; Hobischak et al. 2006; Joy et al. 2006).

Succession research is extremely labour intensive. This has made it difficult to produce replicated data suitable for a traditional type of statistical confidence interval about a PMI estimate (e.g. 20 or more experimental carcasses for one set of conditions, LaMotte and Wells 2000). Computer resampling methods (Schoenly 1992) may overcome this limitation. Therefore there is a great opportunity to increase such computer intensive applications in succession research.

It has long been observed that the adults of different carrion fly species differ in preference for habitat type (Norris 1965). Therefore, it may be possible to determine that a corpse was move following death, if the immature insects in a corpse are not typical of the site where the body occurs (Amendt et al. 2004). Two of the authors (J. A and R. Z) moved piglet carcasses between rural and urban sites in Germany, following one week of exposure to insect colonization, while leaving others in place. Although no carrion insect species was unique to a habitat, habitat-specific difference in the proportion of each species infesting a piglet could identify the habitat in which a carcass was first colonized. However, the experiments demonstrate that caution must be used in determining whether remains have been moved based solely on entomological evidence. Densely populated landscapes, especially in industrialised countries, exhibit no rigid separation of habitats, leading to a mixture of insect species communities.

Frost et al. (this book, chapter 6) discuss the importance of improving our knowledge about indoor arthropods and indoor scenarios: While the majority of cases with insect evidence occur indoors, nearly all insect succession studies take place outside.

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