The influence of winter temperature on fly colonization and developmental rate during a field experiment in Northern Italy

In the years 2006 and 2008, two pig (Sus scrofa) carcasses were exposed in an open field in the beginning of November and left out until they reached complete skeletonization; both pigs were placed in the same open field located in the surroundings of Pavia, a town in northern Italy. The purpose of this study was to observe the entomological species involved in the colonization of the carcasses during the winter season as well as their developmental time, focusing on the potential temperature-related differences. Both carcasses weighed about 40kg and they were both exposed in direct sunlight protected by a metallic cage. Pitfall traps were distributed around the carcasses and air traps were hung from a tree not far from the experimental area. Pictures of the carcasses were taken once a day while entomological samples were taken twice a day during the first two weeks and then once a day or less, depending on weather conditions. Immature stages were in part preserved in EtOH and in part reared on minced meat. Environmental data were recorded and compared to the ARPA weather station data. Winter 2006 and winter 2008 were significantly different in terms of temperature and meteorological conditions: the former was mild and wet while the latter was rigid and characterized by significant amounts of snow. The pig carcass exposed in 2006 was almost immediately colonized by Diptera in the primary sites; the flies continued to lay eggs repeatedly because of the frequent episodes of rain and the mild temperatures. The most abundant species in the first phases of decomposition were Calliphora vicina, Calliphora vomitoria, Lucilia Caesar and Lucilia sericata, while in the most advanced phases of decomposition, we observed members of the genera Fannia and Piophila. Post-mortem consecutive phenomena were observed during the first two weeks of the trial. After that period, very moderate chromatic changes were observed in the head of the carcass, which was also the first place to be colonized by Diptera and the first part of the carcass to become skeletonized. The pig exposed in 2008 was colonized almost exclusively by a single species, Calliphora vicina, which started oviposition in the head; in the spring, this species was replaced by Calliphora vomitoria and Piophila casei. During the first weeks of the trial, the temperature was still mild; after that, temperatures started to decrease and from the end of the month until the middle of February they remained very low. Moreover, this period was also characterized by significant quantities of snow that accumulated around the carcass and on the cage, but not directly on the pig. Because of these temperatures, the first thanatological changes were observed only 20 days after exposure; the bloating phase was never observed and the chromatic phase was not particularly marked and was characterized by a weak gray coloration of the abdomen. The flies continued oviposition until late November, when it began to snow, and interrupted their activity until March when the temperature rose again. Until this moment, the carcass was still in good condition. The maggots born from the eggs laid in November, continued to slowly develop inside the carcass; due to the extremely rigid environmental conditions, maggot development was so slowed down to be synchronous. Due to these circumstances, it was possible to observe the collective maggot migration from the carcass: masses of post-feeding maggots were in fact collected in the pitfall traps around the carcass and their pupation sites were very easily identified. The simultaneous emergence of young adult flies from their underground puparia was also observed

The Life Cycle of Dermestes Frischii (Kugelann, 1792): A Preliminary Study

The aim of this project was to observe several colonies of Dermestes frischii (one of the most abundant species of the Coleoptera family Dermestidae in Northern Italy) to gain a better understanding of the immature developmental stages and to collect morphometric data on the specimens, all of which could potentially find applications in the forensic field. As matter of fact, within the field of forensic entomology, much effort and interest are put on the observation and research of flies (Diptera), for they are the first insects to sense corpses/carcasses and start visiting them a short time after their exposure and therefore are useful in PMI calculation. The family Dermestidae, which is not predatory and which is actually interested in the carcass itself as a source of food for adult specimens and for their immature stages, feed on dehydrated skin, hair, and cartilage and arrive on the remains when almost all fluids are lost, or when at least some part of them is dehydrated. For this reason, Dermestidae is the only family of Coleoptera whose life cycle occurs entirely on the remains. This makes Dermestes sp. an important indicator of the post mortem interval and for this reason, we carried out a preliminary experiment to collect information on their developmental time under certain conditions; indeed, this is an area of study where exhaustive data are still not present. For this experiment, several colonies of D. frischii were reared in an incubator where the temperature was maintained at 27°C and the humidity at 80%. Eggs, immature stages, pupae and adults were sampled, fixed and measured. The duration of the life cycle was measured in each single stage and in total; mortality was also considered in each stage and overall. The results of this preliminary study have shed light on the morphometry of D. frischii as well as on the number of the immature stages of this species at the experimental temperature. Our next step will be to repeat the experiment at higher and lower temperatures to observe the potentially different responses on the life cycle of D. frischii

Identifying unknown specimens using predictive phylogenies for remote forensic education

One significant impact of the COVID-19 pandemic for educators in forensic science was adapting what is traditionally a very applied field to a virtual learning environment. Because of this, science classes with a practical laboratory component had to implement significant adjustments to ensure that student learning objectives were still met, including practical elements. To provide learners with an alternative to a traditional lab exercise in forensic entomology, we designed an exercise to be conducted completely remotely to instruct students in how to identify a real unknown specimen using a hypothetical phylogenetic tree they create. Students retrieved data and make predictions using public databases, generate phylogenies based off sequence data, and finally determine the identity of the unknown sequence provided. This lab replacement exercise has been adapted to be accessible to learners from different academic levels and takes the length of one two-and-a-half-hour lab period to complete. Through creating this resource, we have been able to link molecular systematics to forensic education and provide learners who download this publicly available exercise insight into how forensic questions are answered

Evaluation of Ethyl Glucuronide and Ethyl Sulfate in Calliphora Vicina as Potential Biomarkers for Ethanol Intake

Ethyl glucuronide (EtG) and ethyl sulfate (EtS) are specific and sensitive biomarkers for the diagnosis of acute or chronic alcohol abuse. Due to postmortem alcohol production in biological tissues, they have recently been evaluated as potential biomarkers of ethanol ingestion. This in vitro study aimed to evaluate all developmental stages of the fly Calliphora vicina L. (Calliphoridae). Different pig substrates were used during the in vitro experiments to rear C. vicina Experiments were performed to: (i) assess the presence of EtG and EtS in larvae, pupae and insects; (ii) study variability due to the substrates characteristics; (iii) evaluate the possibility of false positives due to external alcohol contamination; and (iv) estimate the potential metabolism of ethanol by the insects. EtS was found in all of the samples where the standard was added to the substrate. Muscle provided the most reliable results. EtS was found in larvae, pupae and puparia. EtG and EtS were found in larvae and pupae collected from the body of an alcoholic found dead in his home. This study showed that maggots, pupae and puparia could be a useful matrix for the evaluation of antemortem alcohol ingestion

A case study on the integration of cannabis law enforcement in New Jersey

Legalized medical cannabis is implemented in 44 states in the USA while recreational marijuana legislation has challenged the law enforcement community. The public safety concerns of citizens involve a perceived increase in crimes, marijuana being a gateway for hard drug usage, the influx of residents from bordering states, increased fatal crashes, and the depletion of vital resources. In New Jersey, the State Police Forensic Science Laboratory System is the primary support system for law enforcement and laboratory professionals. Several Fatality Analysis Reporting System training programs are offered statewide, while the critical need remains to review enforcement practices. This study examines current medical cannabis enforcement practices to determine pending challenges and establish solutions for the state\u27s oversight of legalized recreational marijuana

Biodiversity of Forensically Relevant Blowflies (Diptera: Calliphoridae) at the Anthropology Research Facility in Knoxville, Tennessee, USA

Understanding the biodiversity and distribution of forensically relevant blowflies (Diptera: Calliphoridae) in a region can aid in legal investigations when insects are associated with remains. For this purpose, we conducted a 14-month-long blowfly survey at the Anthropology Research Facility (ARF) of the University of Tennessee in Knoxville, Tennessee. Traps baited with pork kidney were deployed for 24 h twice a month throughout the study. A total of 3180 adult blowflies were collected, comprising 13 species from 7 genera. Phormia regina (Meigen) and Lucilia coeruleiviridis (Macquart) were the predominant species collected from this survey, with collections representing 65.9% and 20.6%of total flies captured, respectively. In addition to relative abundance, we investigated blowfly community composition, species abundance, richness, and diversity by season. One state record was identified, with adult Protophormia terraenovae (Robineau-Desvoidy) being collected for the first time in Tennessee. Additionally, an earlier record of Chrysomya megacephala (Fabricius) in Tennessee was noted. These findings can be used to aid in legal investigations in the area and surrounding areas where work is limited, as well as to provide information on which forensically relevant species should be the subject of future research in the area

Assessment of Fungal Succession in Decomposing Swine Carcasses (<i>Sus scrofa</i> L.) Using DNA Metabarcoding

The decomposition of animal bodies is a process defined by specific stages, described by the state of the body and participation of certain guilds of invertebrates and microorganisms. While the participation of invertebrates in decomposing is well-studied and actively used in crime scene investigations, information on bacteria and fungi from the scene is rarely collected or used in the identification of important factors such as estimated time of death. Modern molecular techniques such as DNA metabarcoding allow the identification and quantification of the composition of microbial communities. In this study, we used DNA metabarcoding to monitor fungal succession during the decomposition of juvenile pigs in grasslands of New Jersey, USA. Our findings show that decomposition stages differ in a diversity of fungal communities. In particular, we noted increased fungal species richness in the more advanced stages of decomposition (e.g., bloat and decay stages), with unique fungal taxa becoming active with the progression of decay. Overall, our findings improve knowledge of how fungi contribute to forensically relevant decomposition and could help with the assessment of crime scenes