The Micro-Taphonomy of Cold: Differential Microcracking in Response to Experimental Cold-Stresses.

Cold is a central feature of environments at higher latitudes and elevations. Thus, cold-induced taphonomic changes are relevant in many forensic contexts. Fifty-two lamb bone segments were used to assess the impact of cold, freeze-thaw cycles, freeze-drying, and water immersion on microstructural cracking of bone in a series of controlled exposure experiments. For each bone segment, three thin sections were examined under a light microscope. Cold exposure caused taphonomic changes in the form of microscopic cracking. Transverse cracks occurred in all treatments, whereas osteonal cracks were restricted to rapid freezing treatments. Type of cold exposure had a statistically significant effect on both the total number of cracks and each type of crack observed. Skeletal microcracking could potentially be used as a taphonomic indicator of postmortem bone exposure to sub-zero temperatures. The type and prevalence of this damage could also be used to distinguish between different types of cold exposure.

Postfeeding larval dispersal behavior of late season blow flies (calliphoridae) in Southern Ontario, Canada.

Postfeeding dispersal involves migration of larvae away from their food source in order to pupate. Puparia are difficult to find, yet are important for estimating PMI, and missing puparia during collection can result in inaccurate estimations. This study investigates the late season maggot dispersal patterns for blow flies at coyote carcasses in two habitats with an aim to improving puparia collection procedures. Puparia samples collected from various dispersal distances and directions tested the spatial distribution patterns of the various species using the variance/mean ratio (VMR). Lucilia illustris was the most common species to emerge, with a preferred minimum dispersal distance of more than 50.8 cm and an overall VMR value of 14.91, indicating this species had a clumped distribution pattern. These findings highlight that current collection procedures that use random sampling from under carcasses do not adequately account for the spatial distribution of larvae.