Is Forensic Entomology Lost in Space?

Denis R Boudreau,Gaétan Moreau

doi:10.3390/insects13010011

Abstract

Simple SummaryAlthough they affect most parameters that influence insect presence and development, spatial and scale effects are not normally considered in forensic entomology. Here, we documented the spatial dynamics of an important forensic taxon, the Calliphoridae, in the Greater Moncton area of New Brunswick, Canada. Results indicated that regional aggregation patterns of Calliphoridae differed among species and that the spatial relationship between species varied between aggregation and spatial anticorrelation. Overall, this study suggests that the dynamics of forensic insects in space differ in many ways among species, highlighting the importance for forensic entomology to consider spatial effects.Spatial and scale effects have barely been considered in forensic entomology, despite their pervasive influence on most of the parameters affecting the development of insect larval stages and the progression of insect succession on cadavers. Here, we used smoothing/interpolation techniques and semivariograms to document the spatial dynamics of sarcosaprophageous Calliphoridae, an important forensic taxon, in the Greater Moncton area in New Brunswick, Canada. Results indicated that the spatial dynamics of Calliphoridae differed between species, some species showing strong patterns of regional aggregation while others did not. Multivariate spatial correlations indicated that interspecific relationships in space varied widely, ranging from local and large-scale aggregation to spatial anticorrelation between species. Overall, this study suggested that even within a restricted timescale, the spatial dynamics of Calliphoridae can operate at many scales, manifest in different patterns, and be attributed to multiple different causes. We stress that forensic entomology has much to benefit from the use of spatial analysis because many important forensic questions, both at the fundamental and practical levels, require a spatial solution.

Highlights

A fundamental question in forensic entomology is whether certain environmental parameters affect the ability to draw entomological inferences from insects
Forensic entomology has much to gain from the implementation of spatial statistics into its protocols because field data in forensic science are intrinsically composed of several layers of spatial structure
The objective of this paper is to demonstrate what can be gained from the use of spatial statistics in forensic entomology

Summary

Introduction

A fundamental question in forensic entomology is whether certain environmental parameters affect the ability to draw entomological inferences from insects. Spatial and scale effects have barely been considered in forensic entomology [3,4,5,6,7,8], despite their pervasive effects on most of the biotic and abiotic parameters affecting insect occurrence and development. At the local scale, entomological data can be influenced by spatial effects due to heterogeneity in field conditions [11,12], microclimate [13], and movement between cadavers/carcasses of organisms that can synchronize carcass dynamics (i.e., forensic species of interest, predators, parasitoids, scavengers; [14,15]). Many other situations are susceptible to producing a spatial pattern and failure to consider spatial layers can lead, for example, to underestimation of the influence of spatial dynamics on processes, to misattribution of spatial effects to other sources of variation [19], to inaccurate mechanistic inference, to erroneous projections from the data, such as when estimating the postmortem interval, etc

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