title: The impact of buried cadavers on the abundance and diversity of mites
Creators: name: Rai, Jas Kaur
Publisher: name: University of Reading
Year: 2022

description: Mites are the most abundant and diverse micro-arthropods in soils, on the surface or in
deeper layers and form an important part of the grave fauna. They have been overlooked 
in death investigations of buried cadavers because of the lack of knowledge on their
colonisation patterns. The results of this research found that cadaver decomposition in 
shallow graves attracts necrophagous, predatory and omnivorous species of soil and 
phoretic mites and the abundance and colonisation patterns vary in comparison to surface 
(control) cadavers. Cadaver decay caused an increase in soil alkalinity and an increase in
mite abundance in both circumstances. Successional patterns of mite orders and families 
in relation to decay stages was observed. Mesostigmata were the most abundant and 
diverse mites colonising buried and surface cadavers, represented mainly by predatory 
Parasitidae and Macrochelidae and the Prostigmata family Tydeidae, was found to be an
important marker of late decay. We found that there is a delayed colonisation of buried 
cadavers by Parasitidae mites, which first arrive during the bloated stage but are present 
from the fresh stage of surface cadavers. The composition of mite species was similar for 
both, however several different species were markers of decay stages and specific to 
decay in shallow graves. For buried cadavers, Cornigamasus lunaris was associated with 
the bloated stages, Gamasodes spiniger and Parasitus loricatus with active and advanced, 
Eugamasus sp. and Lorryia reticulata with advanced and Macrocheles matrius and 
Ramusella clavipectinata with dry. Trachygamasus sp. was associated with advanced 
decay of surface cadavers, Parasitus coleoptratorum with dry and Macrocheles 
mammifer and Tydeidae sp. with dry. In addition to one Mesostigmata (Pachylaelaps 
longisetis) a handful of Oribatida (soil-dwelling) species were significantly associated 
with control soils (bare) at a shallow depth and on the surface; Ramusella clavipectinata, 
Quadroppia michaeli, Schaeloribates laevigatus and Hoplophora anomla. Furthermore, 
investigation of the attractant and repellent effects of cadaveric volatile organic 
compounds decay (necromones) showed that combinations of necromones had a 
synergistic effect on attracting and repelling soil and phoretic mites. The results revealed
that certain necromones may be key cues in attracting phoretic mites during stages of 
decomposition. In contrast, decay products such as components of adiopocere had a
greater effect on soil-dwelling species. Case work conducted as part of this research 
demonstrated that mite species can be utilised in estimating time of death, in the form of 
a stage of decay and the habitat-specific nature of some mite species can indicate the origin of 
the corpse in cases of relocation. The findings of this research have critical value for time 
of death estimations such as the use of the abundance and succession of mite species as 
markers of stages of decay of buried and surface cadavers.