Aquatic Entomology

Freshwater and marine fauna has received very little attention in forensic investigations (Nuorteva et al. 1974; Goff and Odom 1987; Haskell et al. 1989; Vance et al. 1995; Sorg et al. 1997; Davis and Goff 2000). Knowledge about the role of aquatic arthropods during decomposition is still scant (Keiper et al. 1997; Anderson 2001; Merrit and Wallace 2001; Hobischak and Anderson 2002). Compared to terrestrial habitats, decomposition in an aquatic environment is completely different. It occurs at roughly half the rate as on land, mainly due to the prevention of insect activity and cooler temperatures. Aquatic insects of forensic importance belong to the Ephemeroptera (mayflies), Trichoptera (caddisflies) and Diptera (true flies), the latter are mainly represented by Chironomidae (midges) and Simuliidae (black flies). But even these insects, unlike their terrestrial counterparts, are not obligatory sarcophages, but instead use the submerged carrion as a food source as well as a breeding site. The use of these insects for estimating time of death is more difficult and depends on the season and on other conditions of aquatic systems. Hobischak and Anderson (2002) evaluated whether or not arthropod succession in freshwater environments could be used to estimate the postmortem submersion interval. Although their data revealed a predictable succession of invertebrates, they stated that further studies are necessary to determine if the observed succession was carrion- dependent or season-dependent.

This research team also studied decomposition in a marine environment (Anderson and Hobischak 2004). Their results showed stages of decomposition different from patterns seen on land or in freshwater. Future avenues of research were suggested, such as allowing the carcass to float to the surface (see chapter 12, this book).

Limited work has been done regarding corpses that were allowed to decompose in a terrestrial environment and then transferred to an aquatic environment. Singh and Greenberg (1994) addressed this scenario by studying the effect of drowning on the survival of blowfly pupae. Data from this type of study would be valuable in aquatic cases where puparia (submerged, along with the corpse, after the larvae had pupariated) are discovered on a corpse.

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