Microhabitat Characteristics Determine The Succession of Histeridae on Carcass

This research examines microhabitat influences on Histeridae beetle succession during carcass decomposition in a summer monsoon environment in Punjab, India, to support forensic PMI estimation. The study provides detailed protocols for replication, drawing from the RES Student Forum 2023 poster by Jasvinder Kumar (Panjab University, Chandigarh). No explicit ethical approvals are noted in the materials, but carcass use from a public dump yard implies compliance with local animal disposal norms; institutional review from Panjab University is recommended for confirmation. Study Objectives Determine Histeridae succession patterns across decomposition stages, influenced by temperature (ambient, carcass, subsurface), humidity, and rainfall. Identify forensically relevant species diversity and abundance for PMI accuracy in tropical conditions. Quantify ~5,290 beetles from genera Saprinus, Hister, Pachylister, Atholus, and Merohister. Site and Materials Location: Open field 200 m from Hadda-Rodi animal dump yard, Mullanpur, Punjab (GPS: 30.79432° N, 76.74649° E). Carcass: Naturally deceased buffalo calf (~128 cm length × 54 cm depth), sourced from a dump yard to mimic forensic scenarios. Period: May 19–August 6, 2022 (summer monsoon); multiple trials (e.g., July 23–29, August 3–6). Detailed Methodology Carcass Placement and Monitoring: Position carcass in shaded, open terrestrial site; observe morphological changes daily (fresh: 0–1 day; bloated: 2–3 days; active decay: peak insect activity; advanced decay; dry remains: 4–7 days total). Record purge fluids, odors, and maggot migration. Environmental Data: Measure ambient temperature, carcass internal temperature (probe inserted), subsurface temperature (under carcass/soil), and relative humidity (76–86%) and precipitation daily using standard meteorological tools. poster-for-RES-student-form-2023.pdf​ Sampling Protocol: Collect beetles at three microhabitats—1 ft from carcass, on carcass surface, beneath carcass/soil (dig ~10–20 cm)—at ~08:00–10:00 and 16:00–18:00. Use aspirators or forceps; preserve in 50 ml vials of 90% ethanol. Sample volume: All visible adults; replicate across days/stages. Imaging and Identification: Photograph specimens via Leica stereo zoom microscope at 10–40× magnification. Taxonomic ID to species using keys (e.g., Mazur, 2011; Ohara, 1994); subfamilies Saprininae, Histerinae. Data Recording: Log beetle counts, species, temperatures per stage/day in field notebooks; track humidity (48–86%). Techniques and Analysis Visual succession tracking via daily photos/charts; temperature differentials (e.g., carcass 2–4°C > ambient in active decay). No statistical software is mentioned (raw counts graphed); for replication, use R/SPSS for ANOVA on abundance vs. environment. Decomposition staged per standard forensic protocols (e.g., Byrd & Castner, 2010). Ethical and Legal Considerations Carcass from public dump yard (non-experimental killing); no live animal harm. Adheres to Indian wildlife laws (no protected species); university oversight assumed via supervisors (Panjab University/DAV College). No human subjects. Reproduction Guidelines Replicate in similar monsoon conditions (temp 28–35°C, humidity >70%); use piglet/calf equivalents. Equipment: Digital thermometer probes, hygrometer, ethanol vials, stereo microscope. Data outputs: Tables/graphs of counts and temps (e.g., Table 1: bloated stage carcass 33.6–42°C). Share raw CSV: columns (Date, Stage, Ambient_T, Carcass_T, Below_T, Humidity, Beetle_Count, Species). Validation: Cross-check with refs (Sukontason et al., 2007; Eberhardt & Elliot, 2008). Contact: jas_k10@yahoo.com