BackgroundForensic entomotoxicology is a crucial field that studies the effects of drugs and poisons on carrion-feeding insects, particularly in crime investigations. Hydrogen cyanamide, a plant growth regulator, is hazardous and used in agriculture but is limited in some countries due to its high cost and severe toxicity. The terrestrial isopod Porcellio laevis plays a vital role in soil ecosystems and biosystem management. Accordingly, authors aimed to examine the impact of hydrogen cyanamide toxicity on arthropods, specifically Porcellio laevis, Musca domestica (House flies), and Sarcophaga sp. (Flesh flies) visiting decomposing covered/uncovered rat carrions, which could be relevant in forensic investigations. A total of 20 rats were divided into two control (I and II, covered/uncovered) and two treated groups (III and IV, covered/uncovered, euthanized using hydrogen cyanamide). Arthropods were gathered bi-daily during the initial week and then once daily for a duration of 1 month and were assessed for growth rate. Morphological and histological alterations were analyzed using light and electron microscopes.ResultsThe results revealed that hydrogen cyanamide caused a delay in postmortem interval (PMI) by 22-33 h in certain insect species, particularly in uncovered carrion. Severe damage was observed in the carrions of Groups III and IV, specifically Porcellio laevis.ConclusionA scanning electron microscope (SEM) would be beneficial for scrutinizing insects as postmortem toxicological specimens.

The aim of this study was to investigate the effect of sunlight on the degradation of DNA samples taken from blood stains from different types of surfaces. A blood sample obtained from a single male donor was placed on seven different surfaces (galvanized sheet, iron rod, newspaper, white printer paper, glass, soil, and ceramic panel). Samples were kept, during a 4-week summer period, in a room, but next to an open window. Every 7 days, 1 mm2 of blood sample was collected from each substrate and stored in labeled tube for later analysis. DNA was extracted with the Chelex method, amplified using AmpFISTRTM MinifilerTM Plus Amplification Kit, and quantified using a QuantifilerTM Human DNA Quantification kit. After 7 days of sun exposure, the highest DNA concentration was determined to be from the sample from a galvanized sheet stain, followed by, in order of decreasing concentration, the ceramic panel, glass, newspaper, iron rod, and white printer paper surface. As expected, the DNA concentration from all samples decreased as the sunlight exposure time progressed. The results obtained after the amplification in the MiniFilerTM system were in correlation with the DNA concentrations measured by the qPCR method for all samples, except for the glass, soil, and white printer paper samples. The obtained data show that DNA degradation is correlated to the length of sunlight exposure and to the type of surface the samples are collected from. A negative qPCR result does not mean negative PCR amplification in the STR system; therefore, both methods should be applied when analyzing forensic samples collected from trace evidence.