Characterization and Identification of Puparia of Hydrotaea Robineau-Desvoidy, 1830 (Diptera: Muscidae) From Forensic and Archaeological Contexts

Morphology, biology and molecular characterisation of the endemic Canary Islands blowfly Calliphora splendens Macquart, 1838 (Diptera: Calliphoridae)

The Canary Islands are an excellent natural laboratory for understanding ecological and evolutionary processes such as biogeographical colonisation. The morphology of the larva, puparium and adult of the endemic Canarian copper fly, Calliphora splendens, is described, illustrated and contrasted with those of the other species of Calliphora that occur in Africa, the Iberian Peninsula and Macaronesia. Partial cytochrome oxidase I sequences show a connection between C. splendens, Calliphora vicina, Calliphora loewi and Calliphora croceipalpis, but more distant relationship with Calliphora vomitoria. Calliphora splendens produced unisexual offspring in captivity. This work confirms the relict character of the Canarian copper fly associated with the endemic laurel forest habitat.

Identification of Diptera Puparia in Forensic and Archeo-Funerary Contexts

Diptera identification is fundamental in forensic entomology as well as in funerary archeoentomology, where the challenge is exacerbated by the presence of immature stages such as larvae and puparia. In these two developmental stages, specimens possess a very limited number of diagnostic features, and for puparia, there is also a lack of identification tools such as descriptions and identification keys. Morphological analysis, DNA-based techniques, and cuticular chemical analyses all show good potential for species identification; however, they also have some limitations. DNA-based identification is primarily hindered by the incompleteness of genetic databases and the presence of PCR inhibitors often co-extracted from the puparial cuticle. Chemical analysis of the cuticle is showing promising results, but this approach is also limited by the insufficient profile database and requires specific, expensive equipment, as well as trained personnel. Additionally, to ensure the repeatability of the analysis-a critical aspect in forensic investigations-and to preserve precious and unique specimens from museum collections, non-invasive protocols and techniques must be prioritized for species identification.

Morphological and molecular characterization of puparia of Piophilidae species of forensic relevance

Piophilidae are a small family of Diptera with a worldwide distribution and which are historically associated with human activities. In addition to their economic importance, piophilid larvae can also be of medical and legal relevance. Within a medicolegal context, piophilids are frequently associated with cadavers in advanced stages of decomposition, thus being potentially useful forensic indicators and they have been reported also from archaeo-funerary contexts. An accurate species identification is therefore an essential prerequisite to ensure the reliable analysis of insect material in medical, forensic and archaeological investigations. Identification of the adult piophilid flies is possible because of the availability of identification keys, in contrast immature insects, especially puparia, have been poorly investigated and described. In this paper, puparia of 11 species of forensic interest (Piophila casei, Piophila megastigmata, Parapiophila atrifrons, Parapiophila flavipes, Parapiophila vulgaris, Protopiophila litigata, Liopiophila varipes, Prochyliza nigrimana, Prochyliza xanthosoma and Stearibia nigriceps in subtribe Piophilina and Centrophlebomyia furcata in subtribe Thyreophorina) are described and a molecular analysis, based on the COI sequencing, is presented to show the potential of the molecular approach in their identification.

Back to the Middle Ages: Entomological and Botanical Elements Reveal New Aspects of the Burial of Saint Davino of Armenia

The natural mummy of Saint Davino Armeno (11th century) is preserved in the church of Saint Michele in Foro in the city of Lucca (Tuscany, Central Italy). The body of Davino is one of the oldest Italian mummies of a Saint, and his paleopathological study was performed in 2018. In the present research, we investigated the arthropod fragments and botanical remains collected from the body, coffin, and fabrics of Saint Davino. Entomological analyses outlined the presence of 192 arthropod fragments. Among these, Diptera, Muscidae (Hydrotaea capensis and Muscina sp.), and Phoridae (Conicera sp.) puparia were the most abundant. Regarding Coleoptera, Ptinidae (Anobium punctatum) were the most frequent, followed by Cleridae (Necrobia sp.), Trogidae (Trox scaber), Curculionidae (Sitophilus granarius), and Histeridae (Gnathoncus). Cocoons of Tineidae and Pyralidae moths were found, along with a propodeum joined to the petiole and a mesopleuron of an Ichneumoninae parasitoid. Numerous metamera of Julida and three scorpion fragments were also found. Botanical samples indicated the presence of a quite broad botanical community, including gramineous species, olives, evergreen oaks, and grapevine. Overall, entomological data allow us to argue that Saint Davino was first buried into the soil, probably in a wooden coffin, thus supporting the historical-hagiographic tradition according to which he was buried sub divo in the cemetery of Saint Michele. The preservation of the body as a natural mummy may have been facilitated by burial in a coffin that prevented direct contact of the corpse with the earth. Botanical remains offer confirmation of a late medieval urban environment rich in horticultural areas and trees, giving us a landscape that is very different from the current Tuscan city.

Development and Intrapuparial Characterization of Hydrotaea aenescens (Diptera: Muscidae) Raised at Different Temperatures Under Laboratory Conditions

Species belonging to the Muscidae family are important in the medical-sanitary and forensic fields due to their biology. The intrapuparial stage of Hydrotaea aenescens (Wiedemann, 1830), which represents about 50% of the immature development cycle in muscoid Diptera, has not yet been studied in detail. This study identifies and describes the main temporal morphological changes that occur in the pupal body of H. aenescens during its development at 22, 27, and 32 ± 1°C, RH 60 ± 10% with a 12-hr photoperiod. Ten pupae were collected, sacrificed, and fixed every 3 hr after pupariation up to 24 hr, and every 6 hr thereafter until the first emergence. Emergence took place at 282, 174, and 126 hr at 22, 27, and 32°C, with 520, 340, and 260 pupae, respectively. External morphology was described and recorded at eight development stages: pupariation, pre-pupae, early and late cryptocephalic pupae, phanerocephalic pupae, pupae-adult apolysis, pharate adults, and imago, employing 18 key morphological characters for pupae age. These morphological pupae characters, comprise, therefore an alternative and/or additional method to aid in determining the minimum Postmortem Interval (minPMI).

Life Cycle and Biometric Study of Hydrotaea capensis (Wiedemann, 1818) (Diptera, Muscidae), a Species of Forensic Interest

Simple Summary

From the point of view of forensic entomology, the study of the development times of the species and the factors conditioning them are issues of great importance to estimate the minPMI. Hydrotaea capensis is a Muscidae (Diptera) of forensic interest because of its colonization preferences. Thus, there is a need to have more precise data about its biology to gain insights into the interpretation of its presence in corpses. In this study, the H. capensis life cycle was studied at four constant temperatures, 18, 20, 25 and 30 °C, by recording the duration of its different developmental stages and the length reached in each larval stage, as well as some biometric characteristics of the emerged adults. Our work is the first to provide data on the duration of the life cycle of this species and pointed to some alar features as relevant biometric adult indicators to be considered.

Abstract

One of the most important and perhaps most used applications of forensic entomology concerns the estimation of the minimum post-mortem interval (minPMI), defined as the time interval between death and the actual finding of a corpse. Some Diptera species are critical in these studies because they are the first ones capable of detecting and finding a corpse and are selectively attracted by its decomposing status. Thus, the knowledge of the micromorphology of their preimaginal stages and of their life cycles within a time frame constitutes solid indicators for estimating the minPMI. Hydrotaea capensis is a Muscidae of forensic interest usually considered as a late colonizer of corpses. It is widely distributed, living mainly in warm regions, and present in a wide variety of habitats. In this study, the H. capensis life cycle was studied at four constant temperatures, 18°, 20°, 25° and 30 °C, by recording the duration of its different developmental stages, including the length reached in each larval stage, as well as some biometric characteristics of the emerged adults. Significant differences were observed in the average time of development of most larval stages, with a longer duration at low temperatures, and in the length of each larval stage depending on the temperature, but, in this case, without a clear pattern. Moreover, significant differences were found in some alar features, pointing to them as a relevant indicator to be considered. The data provided will assist forensic entomologists to make more accurate minPMI estimations in cases where H. capensis is present.

Post-Mortem Interval Estimation Based on Insect Evidence: Current Challenges

During death investigations insects are used mostly to estimate the post-mortem interval (PMI). These estimates are only as good as they are close to the true PMI. Therefore, the major challenge for forensic entomology is to reduce the estimation inaccuracy. Here, I review literature in this field to identify research areas that may contribute to the increase in the accuracy of PMI estimation. I conclude that research on the development and succession of carrion insects, thermogenesis in aggregations of their larvae and error rates of the PMI estimation protocols should be prioritized. Challenges of educational and promotional nature are discussed as well, particularly in relation to the collection of insect evidence.

Comparison of Accumulated Degree-Days and Entomological Approaches in Post Mortem Interval Estimation

Simple Summary

Among the investigative questions to define the temporal frame of a criminal event, the time since death plays a fundamental role. After death, the body goes through a series of physical and chemical transformations—known as decomposition. The way in which different parts of the body undergo these transformations can be quantified with a scale of scores (TBS, the total body score) and used for the time since death evaluation using the accumulated degree-days (ADDs) parameter, which accounts for time and temperature. This method is reported as TBS/ADD. Another way to estimate the time since death is based on the insect development on the body. Flies represent the first body coloniser and the development of their immature stages is used to define the time of colonisation that is temperature dependent and species specific. In this study, the two methods were compared based on 30 forensic cases occurring in northern Italy. The results highlighted the limits of the TBS/ADD method and the importance of the entomological approach, keeping in mind that with insects the colonization time is evaluated. This time is the minimum time since death.

Abstract

Establishing the post mortem interval (PMI) is a key component of every medicolegal death investigation. Several methods based on different approaches have been suggested to perform this estimation. Among them, two methods based their evaluation on the effect of the temperature and time on the considered parameters: total body score (TBS)/accumulated degree-days (ADDs) and insect development. In this work, the two methods were compared using the results of minPMI and PMI estimates of 30 forensic cases occurring in northern Italy. Species in the family Calliphoridae (Lucilia sericata, Calliphora vomitoria and Chrysomya albiceps) were considered in the analyses. The results highlighted the limits of the TBS/ADD method and the importance of the entomological approach, keeping in mind that the minPMI is evaluated. Due to the fact that the majority of the cases occurred in indoor conditions, further research must also be conducted on the different taxa to verify the possibility of increasing the accuracy of the minPIM estimation based on the entomological approach.

Puparia Cleaning Techniques for Forensic and Archaeo-Funerary Studies

Simple Summary

In forensic entomology, the correct identification of the species colonizing a body is fundamental. In old cases, puparia of Diptera represent the only entomological evidence available. Their identification is made particularly difficult not only because the lack of identification keys, but also because the presence on their surface of elements (dust, soil, dry decomposition fluids, bacteria, etc.) that can cover the diagnostic characters. Because of their fragility and the low amount of DNA, six cleaning techniques based on chemical and physical treatments have been tested. The results of this study indicate that cleaning via warm water/soap, the sonication and treatment with a sodium hydroxide solution are the best methods to achieve a good quality of the samples.

Abstract

Diptera puparia may represent both in forensic and archaeo-funerary contexts the majority of the entomological evidence useful to reconstruct the peri and post-mortem events. Puparia identification is quite difficult due to the lack of identification keys and descriptions. In addition, external substances accumulated during the puparia permanence in the environment make the visualization of the few diagnostic characters difficult, resulting in a wrong identification. Six different techniques based on physical and chemical treatments have been tested for the removal of external substances from puparia to make identification at species level feasible. Furthermore, the effects of these methods on successful molecular analyses have also been tested as molecular identification is becoming an important tool to complement morphological identifications. The results of this study indicate that cleaning via warm water/soap, the sonication and treatment with a sodium hydroxide solution are the best methods to achieve a good quality of the samples.

The optimal post-eclosion interval while estimating the post-mortem interval based on an empty puparium

The puparium is the hardened exoskeleton of the last larval instar of a fly, inside which a prepupa, a pupa and a pharate adult fly successively develop. Empty puparia are frequently collected at death scenes, especially in cases with a long post mortem interval (PMI). Although we are not able to estimate the interval between the eclosion of an adult fly and the collection of an empty puparium (i.e. the post-eclosion interval (PEI)), empty puparia may still provide valuable evidence about the minimum PMI. However, because of the unknown PEI, it is impossible to determine the time when the fly emerged, and thus when the retrospective calculation of the minimum PMI should start. In this study, the estimation of PMI (or minimum PMI) for empty puparia of Protophormia terraenovae Rob.-Desv. (Calliphoridae) and Stearibia nigriceps Meig. (Piophilidae) was simulated, to gain insight into the changes in estimates, when different PEIs and different temperature conditions were assumed. The simulations showed that the PEI (in a range of 0–90 days) had no effect on the PMI (or minimum PMI) when the puparium was collected in winter or early spring (December–April). In late spring, summer, or autumn (May–November) the PMI (or minimum PMI) increased with the PEI. The increase in PMI was large in the summer months, and surprisingly small in the autumn months, frequently smaller than the PEI used in the estimation. The shortest PMI was always obtained with a PEI of 0, indicating that the true minimum PMI is always estimated using a PEI of 0. When the puparium was collected during spring, simulations indicated that oviposition had occurred in the previous year, while in summer the previous-year oviposition has been indicated by the simulations only when longer PEIs had been assumed. These findings should guide estimation of the PMI (or minimum PMI) based on an empty puparium.

Description of the puparium and other notes on the morphological and molecular identification of Phthitia empirica (Diptera, Sphaeroceridae) collected from animal carcasses

Background

A correct identification of species is fundamental in order to derive all the biological, ecological, and behavioral information useful to reconstruct previous events when insects are used in forensic and funerary archaeological contexts. Little attention was paid in the past to the description of the immature stages of flies, especially of species belonging to family found only occasionally on human cadavers and animal carrion. Sphaeroceridae species belong to this category.

Results

In this work, adult and puparia of Phthitia empirica (Hutton, 1901) are illustrated and described. In addition, some observations about the molecular identification of this species are presented and discussed.

Conclusions

This work will allow the identification of puparia of this species providing additional tools in forensic entomological investigation. More in general, the effort of producing morphological descriptions and molecular information of species of potential forensic interest clearly implements the possibility to provide a deeper understanding of the peri- and post-mortem events in violent crimes.

Insights on Funeral Practices and Insects Associated With the Tombs of King Ferrante II d'Aragona and Other Renaissance Nobles

The impressive Sacristy of the Basilica of San Domenico Maggiore contains 38 wooden sarcophagi with the bodies of 10 Aragonese princes and other Neapolitan nobles, who died in the 15th and 16th centuries. To improve the knowledge about the entomofauna associated with bodies in archaeological contexts, herein we provide insights on the funerary practices and the insect community associated to Ferrante II King of Naples and other Italian Renaissance mummies of the Aragonese dynasty buried in the Basilica of St. Domenico Maggiore. We identified 842 insect specimens: 88% were Diptera (Muscidae, Fanniidae, and Phoridae), followed by 9% Lepidoptera (Tineidae) and 3% Coleoptera (Dermestidae and Ptinidae). Ninety-seven percent of the specimens were collected from the coffin of Francesco Ferdinando d'Avalos, which was the best preserved. A lack of fly species characterizing the first colonization waves of exposed bodies was noted. The most common fly was the later colonizing muscid Hydrotaea capensis (Wiedemann); only a few Fanniidae (Fannia spp.) were retrieved. The lack of blowflies, coupled with recording H. capensis as the dominant fly, supports our hypothesis that corpses have been kept indoors for a long time under confined environmental conditions. Other explanations include odorous oils/balms having been used in the embalming process, causing the delay or stopping the arrival of first colonizer flies. Hermetically sealing of the coffin with bitumen may also have played a role in preventing access to the corpses. This scenario describes a historical context characterized by a well-advanced knowledge of body preparation, with specific burial techniques adopted for nobles.

First report of Heleomyzidae (Diptera) recovered from the inner cavity of an intact human femur

One of the main characteristics of the Mafia of Gargano is their use of ritual murders: they shoot their victims in the face and then conceal the corpses in the numerous natural ravines present in the Gargano area. Skeletal remains are often recovered in a poor state of preservation under particular conditions related to the environmental situation. Humidity, temperature and environmental contaminants could be considered very important for forensic examinations and are strictly related to the bone preservation status. One of the most important analyses is the identification of the victim: the success rate is linked to the condition of the bones. During military investigations in the Gargano area, several bones were recovered and analyzed in a karst ravine about 30 m deep. The forensic examination highlighted the presence of fly puparia from an intact human femur. The colonization of the inner bone cavity by a species of the Heleomyzidae family is described for the first time. Puparia, despite not being identified at the species level, are described and illustrated and their potential role in the degradation of the victim's DNA is discussed. This work increases our knowledge about the effects of Diptera in the taphonomic process underlying the need of a multidisciplinary approach to skeletal investigations.

Record of Leptometopa latipes (Diptera: Milichiidae) from a human cadaver in the Mediterranean area

In forensic entomology, insects are used mainly to obtain information about the time since death. This information is obtained studying the developmental rate of the first colonizers, principally species in the families Calliphoridae, Sarcophagidae, Muscidae, Stratiomyidae and Phoridae. However, species belonging to other families can provide information about body transfer or the season of the death. Among them Milichiidae are flies rarely reported from human cases despite the larvae of some species are known as saprophagous feeding on plant and animal decomposing matter. A potential cause of the lack of records of these species from forensic cases can be related with the paucity of descriptions and illustrations of the immature stages. In this article, the entomological samples collected from a human body found inside an apartment in a Maghreb country, in Northern Africa, is reported and Leptometopa latipes (Diptera: Milichiidae) is described in detail. Molecular analysis is also reported to confirm the morphological analysis.