Assemblages of Acari in shallow burials: mites as markers of the burial environment, of the stage of decay and of body-cadaver regions

Abstract

The burial of a cadaver results in reduced arthropod activity and disruptions in colonisation patterns. Here, the distribution and diversity of mite taxa was studied across decomposition stages of shallowly buried pig carcasses (Sus scrofa domesticus). In total 300 mites (88 species) were collected from three pig shallow graves compared to 129 mites (46 species) from control (bare) soil samples at the same depth. A successional pattern of Acari higher taxa and families was observed, and species richness and biodiversity fluctuated throughout decomposition, whereas active decay showed the greatest biodiversity. Mesostigmata mites were the most abundant in ‘cadaver soils’ with a significant difference in the abundance of Parasitidae mites, whereas Oribatida mites (true soil mites) were the most abundant in control soils. Certain mite species were significantly associated with decay stages: Cornigamasus lunaris with ‘bloated’, Gamasodes spiniger with ‘active’, Eugamasus sp. and Lorryia reticulata with ‘advanced’, and Macrocheles matrius and Ramusella clavipectinata in ‘dry’. Scheloribates laevigatus was a marker of bare soil at a shallow depth and Vulgoramasus remberti of buried decomposition, not specific to any decay stage. Analysis of mite assemblages associated with head, torso and posterior body showed that Parasitus evertsi and M. matrius are attracted to beneath the thighs, whereas L. reticulata to beneath the head. This study highlights the value of mites as indicator species of decomposition and its stages, confirming (1) a succession of Acari on buried remains and (2) species specificity to body regions.

The impact of the decomposition process of shallow graves on soil mite abundance

“…This last point demonstrates that the increase in soil pH due to decomposition is the major environmental parameter influencing the abundance of mites in shallow graves. The identification of the Acari from this study is being carried out [ 78 ], and the analysis of data at order, family, and species level, aims to compare diversity with stages of decomposition as well as body parts in the shallow grave environment.…”

A new species of Scatoglyphus Berlese (Acariformes: Astigmata: Scatoglyphidae) associated with nests of the fungus growing ants Acromyrmex lundi (Guérin-Méneville) (Formicidae: Myrmicinae: Attini)

“…Zachvatkin andVolgin (1956 cited in Schatz et al 2011) erected the family Scatoglyphidae to accommodate this genus. Since the mention of this mite by Berlese, the genus was recorded in many habitats and localities from Asia, Europe, North America and north of Africa: chicken manure in USSR (Zakhvatkin 1941, cited in OConnor 2009, Egypt (El-Bishlawy 1989; Nasr Eldin 2017), Brazil (Barbosa et al 2013), but also in an owl nest in USA (OConnor 2009); other findings extend their range to firewood, in China (Fang et al 2021), pig (Sus scrofa domesticus) carcasses in a decomposition study in England (Rai et al 2021), and ant nests in Argentina (Porta and Martínez 2010).…”

The arthropods of corpses from above ground and from deep below

“…Over 150 years ago, Jean Pierre Mégnin proposed that mites arrive at corpses at two particular stages of the decomposition process, that is within the first and the sixth waves of arthropod arrival or colonisation event (Mégnin, 1895). Now we know that mites actually arrive at each stage of the decomposition process of corpses, in a continuum (Rai et al, 2021). Interestingly, the mite fauna of cadavers is very diverse, and mite species composition varies as decomposition progresses and according to the environment where decomposition occurs (Baker, 2009;.…”

“…These corpses will be exposed to phoretic as well as to soil and epigean mites living in the upper layer of the substratum (Fig. 1-A) (Rai et al, 2021). Despite being buried superficially, the occurrence and abundance of mite species are mainly dictated by the composition and chemistry of the soil and by the surrounding soil pH (Rai et al, 2022).…”