Necrophagous Insects Found in the Surroundings of Buried Bodies

Within the microfauna, necrophagous insects are said to be the most important factors after temperature, impacting the decomposition rate (Mann et al. 1990). Burial significantly inhibits access of scavengers to the cadaver. Necrophagous insects are attracted by decaying odours, which are masked by the soil covering above the body. Some of them can reach the decaying body through cracks in the soil created either by bloating of the body (Rodriguez and Bass 1985), crevices caused by dry weather or holes dug by rodents or other predators (Gaudry E, unpublished observation). Adult females can then lay eggs directly on the surface of the body. In some species, females lay eggs on the surface of the soil. After hatching, young first instars migrate into the soil to reach the body, feed and develop (Smith 1986; Rodriguez and Bass 1985).

Rodriguez and Bass (1985) reported the following observations. Cadavers buried at 1.2 m (4 ft) for 1 year showed a good state of preservation. No carrion insect activity was observed on corpses buried at 0.6 m (2 ft) for 6 months either. Cadavers buried at 0.3 m (1 ft) for 3 months was decomposed and numerous larvae of Diptera, pupae, puparium and adults were observed. Their identification revealed that they belong to the Calliphoridae and Sarcophagidae family (Table 13.4). Cadavers buried at 0.3 m (1 ft) for two and a half months and for 1 month exhibited few larvae of Diptera.

In this study, authors observed that the adults of Calliphoridae not only try to reach the cadaver through small cracks and crevices in the soil, but also by oviposi-tion in the soil cracks following heavy rain.

Cold and anoxic conditions favour preservation of a carcass even at shallow depth but at the same time may significantly inhibit insect colonization. Turner and Wilshire (1999) started a 5-month experiment in winter and observed only Calliphoridae after 4 months: Calliphora vomitoria, Lucilia sp.; Muscidae: Phaonia sp.; Phoridae: Conicera tibialis and Silphidae: Nicrophorus investigator (Table 13.4).

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