Multilocus and multiregional phylogeny reconstruction of the genus Sarcophaga (Diptera, Sarcophagidae)

The genome sequence of the variegated flesh fly, Sarcophaga variegata (Scopoli, 1763)

We present a genome assembly from an individual male Sarcophaga variegata (the variegated flesh fly; Arthropoda; Insecta; Diptera; Sarcophagidae). The genome sequence is 718.5 megabases in span. Most of the assembly is scaffolded into 7 chromosomal pseudomolecules including the X and Y sex chromosomes. The mitochondrial genome has also been assembled and is 18.7 kilobases in length. Gene annotation of this assembly on Ensembl identified 16,660 protein coding genes.

The genome of Roselle's flesh fly Sarcophaga ( Helicophagella) rosellei (Böttcher, 1912)

We present a genome assembly from an individual male Sarcophaga rosellei (Roselle's flesh fly; Arthropoda; Insecta; Diptera; Sarcophagidae). The genome sequence is 541 megabases in span. Most of the assembly is scaffolded into six chromosomal pseudomolecules, with the X sex chromosome assembled. The mitochondrial genome has also been assembled and is 19.5 kilobases in length. Gene annotation of this assembly on Ensembl has identified 15,437 protein coding genes.

Wing measurements are a possible tool for the identification of European forensically important Sarcophagidae

The flesh flies are a group of insects well known for their forensic importance. Reliable identification of these flies relies on the use of either molecular markers or the morphology of the male genital apparatus. Identification of female flesh flies is more time consuming and less reliable than their male counterparts. This is particularly problematic for forensic entomology practitioners, because female flesh flies are more abundant than males in carrion arthropod assemblages. As such, it is critical that alternative methods for flesh fly identification are established that are equally effective for both sexes. One promising technique is the use of wing measurements, which have been shown to be reliable for the identification of some groups of necrophagous Diptera from several geographical regions. We applied this method to the European Sarcophagidae for the first time, using a dataset of 881 specimens representing 29 species and 5 genera. Species identifications were based on 15 landmarks located at wing vein junctions. We also combined our results with data from previous studies of Calliphoridae and Muscidae which utilised the same methodology, enabling the testing of family level identification using wing morphometrics. Species identifications using wing measurements had varied success. While some species were successfully identified without error, others, particularly from the genus Sarcophaga, were often misclassified. Notably, in several species wing measurements successfully identified both males and females. The results presented here suggest that wing measurements are a promising complementary method to other methods for the identification of necrophagous Sarcophagidae especially in material unsorted at the family level. It can also be used to double check identification performed by a taxonomist using traditional methods.

A phylotranscriptomic framework for flesh fly evolution (Diptera, Calyptratae, Sarcophagidae)

The Sarcophagidae (flesh flies) comprise a large and widely distributed radiation within the Calyptratae (Diptera). Larval feeding habits are ecologically diverse and include sarcosaprophagy, coprophagy, herbivory, invertebrate and vertebrate predation, and kleptoparasitism. To elucidate the geographic origin and evolution of flesh fly life-history, we inferred a backbone phylogeny based on transcriptomic data from 26 sarcophagid species covering all three subfamilies plus 15 outgroups. The phylogeny was inferred using maximum parsimony and maximum likelihood methods based on a series of supermatrices, one set with overall information content improved by MARE (2290 loci), one set with 100% gene coverage for all included species (587 loci), and the last set including mitochondrial and nuclear genes (589 loci) and additional taxa. In order to obtain a more detailed hypothesis, we utilized the supertree approach to combine results from the present study with previously published hypotheses. This resulted supertree covers 84 of the one hundred currently recognized sarcophagid genera and formed the basis for the ancestral state reconstructions. The monophyletic Sarcophagidae is well-supported as sister to {Mystacinobiidae + Oestridae}, and relationships at the subfamily level are inferred as {Sarcophaginae, (Paramacronychiinae + Miltogramminae)}. The Sarcophagidae and each subfamily originated in the Americas, with Sarcophaginae diversifying mainly in the Neotropics, whereas the major radiation of both Miltogramminae and Paramacronychiinae occurred in the Palaearctic. Sarcosaprophagy is reconstructed as the ancestral larval feeding habit of the family Sarcophagidae and each subfamily. The ancestral sarcophagid larva probably utilized dead invertebrates as food, and the food spectrum expanded together with the diversification of breeding strategies. Particularly, kleptoparasitism in Miltogramminae is derived from sarcosaprophagy and may be seen as having derived from the breeding biology of 'lower' miltogrammines, the larvae of which feed on buried vertebrate carrion.

Museomics and phylogenomics with protein-encoding ultraconserved elements illuminate the evolution of life history and phallic morphology of flesh flies (Diptera: Sarcophagidae)

BACKGROUND

The common name of the Flesh flies (Sarcophagidae) usually relates them with organisms feeding on decomposing organic matter, although the biology of one of the largest radiations among insects also includes predation, coprophagy, and even kleptoparasitism. The question of whether the ancestor of all sarcophagids was a predator or a decomposer, or in association to which host have sarcophagids evolved, has thus always piqued the curiosity of flesh fly specialists. Such curiosity has often been hindered by both the impossibility of having a well-supported phylogeny of Sarcophagidae and its sister group to trace live habits and the scarcity of information on the biology of the group. Using a phylogenomic dataset of protein-encoding ultraconserved elements from representatives of all three subfamilies of Sarcophagidae as ingroup and a large Calyptratae outgroup, a robust phylogenetic framework and timescale are generated to understand flesh fly systematics and the evolution of their life histories.

RESULTS

The evolutionary history for Sarcophagidae reconstructed here differs considerably from previous hypotheses. Within subfamily Sarcophaginae, a group of predatory flies, including genera Lepidodexia and Boettcheria, emerged as sister-group to the rest of Sarcophaginae. The genera Oxysarcodexia, Ravinia, and Tricharaea, long considered archaic and early-branching coprophagous and sarcosaprophagous lineages, were found nested well within the Sarcophaginae as sister-group to the sarcosaprophagous Microcerella. Predation on invertebrates is suggested as the ancestral and dominant strategy throughout the early evolution of flesh flies. Several transitions from predation to sarcosaprophagy and coprophagy occur across the sarcophagid phylogenetic tree, in contrast with almost no transitions from sarcosaprophagy or coprophagy to predatory habits. Regarding the morphological evolution of flesh flies, there might be a concerted evolution of male genitalia traits, such as the phallotrema position and the juxta, or the vesica and the folding of the phallotrema. One diversification rate shift was inferred in the evolution of sarcophagids, which is related to the origin of genus Sarcophaga.

CONCLUSIONS

This study has a significant impact on understanding sarcophagid evolution and highlights the importance of having a robust phylogenetic framework to reconstruct the ancestral character state of biological and morphological characters. I discuss the evolution of life histories of the family in relation to their hosts or substrates and outline how sarcosaprophagy, coprophagy, and kleptoparasitism behavior on various hosts may have evolved from predation on invertebrates. This study provides a phylogenetic framework for further physiological and comparative genomic work between predatory, sarcosaprophagous, coprophagous, and kleptoparasitic lineages, which could also have significant implications for the evolution of diverse life histories in other Diptera.

Human myiasis cases originating and reported in africa for the last two decades (1998-2018): A review

The article reviews literature on myiasis in Africa and cases that originated in Africa over the last two decades (1998-2018). The relevant literature was obtained by using several databases (Science-Direct, JSTOR, Google Scholar, Ebscohost and PubMed). We searched for the following words or their combination myiasis, maggots, fly species responsible for myiasis found in Africa, and the different types of myiasis. References in several articles provided links to other relevant works. Only papers written in English were reviewed. In total, we reviewed 51 articles which covered a total of 849 myiasis cases. The review encompasses geographical distribution of the disease, dipteran species responsible, predisposing factors, sex of the patient, type of myiasis and treatment. Myiasis is found in most parts of the African continent, however only 18 articles reported myiasis cases in Africa during the period under review. The rest of the articles report cases from the rest of the world but acquired by travellers when visiting Africa. Cordylobia anthropophaga (Blanchard) was responsible for 93.28% of all the reported cases in this review. The low number of articles on human myiasis reported in Africa may be due to underreporting by physicians or most cases are not diagnosed. Therefore, the actual prevalence of myiasis in Africa is currently unknown.

Comparative analysis of mitochondrial genomes among the subfamily Sarcophaginae (Diptera: Sarcophagidae) and phylogenetic implications

The subfamily Sarcophaginae is extremely diverse in morphology, habit and geographical distribution, and usually considered to be of significant ecological, medical, and forensic significance. In the present study, 18 mitochondrial genomes (mitogenomes) of sarcophagid flies were first obtained. The rearrangement and orientation of genes were identical with that of ancestral insects. The degrees of compositional heterogeneity in the datasets were extremely low. Furthermore, 13 protein-coding genes were evolving under purifying selection. The phylogenic relationship of the genus-group taxa Boettcheria + (Sarcophaga + (Peckia + (Ravinia + Oxysarcodexia))) was strongly supported. Four subgenera were recovered as monophyletic (Liopygia, Liosarcophaga, Pierretia, Heteronychia) in addition to Parasarcophaga as polyphyletic. The sister-relationships between S. dux and S. aegyptiaca, S. pingi and S. kawayuensis were recovered, respectively. Moreover, the molecular phylogenetic relationships among the subgenera Helicophagella, Kozlovea, Kramerea, Pandelleisca, Phallocheira, Pseudothyrsocnema, Sinonipponia and Seniorwhitea were rarely put forward prior to this study. This study provides insight into the population genetics, molecular biology, and phylogeny for the subfamily Sarcophaginae, especially for the subgeneric classification of Sarcophaga. However, compared with the enormous species diversity of flesh flies, the available mitogenomes are still limited for recovering the phylogeny of Sarcophaginae.

Molecular identification of forensically important fly species in Spain using COI barcodes

Species identification with DNA barcodes has been proven to be effective on different organisms and, particularly, has become a routinely used and quite accurate tool in forensic entomology to study necrophagous Diptera species. In this study, we analysed 215 specimens belonging to 42 species of 17 genera, from 9 different Diptera families. Flies were collected in 39 Spanish localities of the Iberian Peninsula sampled across three years in the four seasons. Intraspecific variation ranged from 0 to 2.46% whereas interspecific variation fluctuated from 3.07 to 14.59%, measuring 651 pb of the cytochrome oxidase subunit one (COI) gene. Neighbour-Joining analysis was carried out to investigate the molecular identification capabilities of the barcoding region, recovering almost all species as distinct monophyletic groups. The species groupings were generally consistent with morphological and molecular identifications. This work, which is the first with this intensive and extensive sampling in this area, shows that the COI barcode is an appropriate marker for unambiguous identification of forensically important Diptera in Spain.

DNA Barcodes for Forensically Important Fly Species in Brazil

Here, we analyze 248 DNA barcode sequences of 35 fly species of forensic importance in Brazil. DNA barcoding can be effectively used for specimen identification of these species, allowing the unambiguous identification of 31 species, an overall success rate of 88%. Our results show a high rate of success for molecular identification using DNA barcoding sequences and open new perspectives for immature species identification, a subject on which limited forensic investigations exist in Tropical regions. We also address the implications of building a robust forensic DNA barcode database. A geographic bias is recognized for the COI dataset available for forensically important fly species in Brazil, with concentration of sequences from specimens collected mainly in sites located in the Cerrado, Mata Atlântica, and Pampa biomes.

DNA barcoding for identifying synanthropic flesh flies (Diptera, Sarcophagidae) of Colombia

The first step for a successful use of any insect as indicator in forensic sciences is providing a precise taxonomic identification at species level. Due to morphology-based identification of Sarcophaginae flies (Diptera, Sarcophagidae) is often difficult and requires strong taxonomic expertise, their use as forensic indicators has been limited. Consequently, molecular-based approaches have been accepted as alternative means of identification. Thus, we aimed testing the efficiency of the barcode region of the mitochondrial cytochrome oxidase subunit I (COI) gene for identification of synanthropic flesh flies of several species of the genera Peckia, Oxysarcodexia, Ravinia, and Tricharaea collected in Colombia. The 645-bp fragment of COI was amplified and aligned (215 parsimoniously informative variable sites). We calculated Kimura two-parameter genetic distances and reconstruct a Neighbor-Joining phylogenetic tree. Our Neighbor-Joining tree recovered all species as monophyletic, and confirmed a new species of the genus Ravinia as also indicated by the interspecific genetic divergences and morphological observations. We obtained a 100% of identification success. Thus, the COI barcodes showed efficiency as an alternative mean of identification of species of flesh flies collected on decaying organic matter in Colombia.

A brief review of forensically important flesh flies (Diptera: Sarcophagidae)

Forensic entomology could provide valuable data for the minimum postmortem interval (PMImin) estimation and other relevant information, such as causes and circumstances of death. Some representatives of flesh flies are one of the dominant necrophagous insects during early stages of decomposition, demonstrating unique biological characteristics compared with other necrophagous flies. Moreover, they lead to global health concerns as carriers of various pathogenic micro-organisms, and dominantly result in the traumatic myiasis. Thus, sarcophagid flies are considered important in decomposition processes for PMImin estimation. However, the utility of sarcophagid flies has been seriously hampered by limited ecological, biological and taxonomic knowledge of them. The aim of this paper is to provide a brief review on the species, distribution and biological habit of forensically important sarcophagid flies. In addition, the relation between traumatic myiasis and flesh flies, molecular identification methods and developmental pattern of flesh flies are summarized.