Molecular Phylogeny of the Oestroidea

The superfamily Oestroidea includes approximately 9% (≈14,000 spp.) of the order Diptera. Many members of the superfamily are of medical, veterinary, agricultural, and forensic importance. Although Oestroidea has been the subject of much scientific scrutiny, the exact patterns of phylogenetic relationships among the key groups of the superfamily are unresolved and controversial. For a better understanding of oestroid evolutionary hypotheses, phylogenies of Oestroidea were reconstructed at several taxonomic levels using DNA sequence data. The specific aims were to determine the phylogeny of the 1) genus Chrysomya (Chrysomyinae); 2) subfamily Chrysomyinae (Calliphoridae); 3) family Oestridae (Oestroidea); and 4) family Calliphoridae (Oestroidea). Sequence data from both mitochondrial and nuclear genes from 99 representative species were analyzed using maximum parsimony (MP), maximum likelihood (ML) and Bayesian (BA) methods. Trees obtained from the different phylogenetic methods were almost identical. The status of family Calliphoridae (the blow flies) has for years been the central systematic problem of the superfamily. These results show that Calliphoridae is polyphyletic, with the phylogenetic position of Mesembrinellinae still uncertain but clearly outside the lineage that includes other Calliphoridae and some non-calliphorids, and Polleniinae is the sister group of the family Tachinidae. Strong support for a sister group relationship between Rhiniinae and traditional calliphorid subfamilies undermines a recent proposal to give Rhiniinae family status. The Chrysomya and Chrysomyinae phylogenies were well resolved and suitable for testing a number of existing evolutionary hypotheses. The Chrysomyinae colonization of the neotropics apparently involved a single ancestral species, and the traditional chrysomyinae tribal classification should be abandoned. Tuberculate larvae evolved twice within Chrysomya, and published hypotheses about the evolution of sex determination, eye morphology, and genome size within the genus appear to be incorrect. Efforts to resolve the relationships of the Oestroid families were largely inconclusive, although the monophyly of the superfamily was strongly supported

A Comparison of Three DNA Extraction Methods on 45-year-old Pupae Cases

Blow flies are the primary colonizers of human cadavers. In many death investigations, insect evidence can help in prediction of minimum post-mortem interval (PMImin) but to do that, the first step is to identify collected insect evidence. For immature stages, morphological keys are either limited or incomplete and hence DNA based identification is used. For DNA based ID, DNA extraction is the first and the most important step, especially when collected evidence is highly degraded. The main aim of this study was to compare three DNA extraction methods (QIAgen Blood and Tissue Kit, organic, and QIAgen DNA Investigator Kit) to determine the quantity of recovered DNA from 45-year-old pupal cases. To accomplish this goal, each pupal case (n=10 for QIAgen Blood and Tissue Kit, n=5 for organic extraction, and n=5 for QIAgen DNA Investigator Kit) was used as a sample for DNA extraction for each method. Extracted DNA was quantified using the Qubit fluorometer. Extracted DNA (only from QIAgen Blood and Tissue Kit and organic method) was then amplified for mitochondrial cytochrome oxidase one (COI) gene and amplification success was visualized using agarose gel electrophoresis. Mitochondrial COI gene amplification didn’t result in a PCR product from any sample. Results from this study indicated that the QIAgen Blood and Tissue Kit is a significantly better DNA extraction method than the QIAgen DNA Investigator Kit for highly degraded pupal cases, as this method yielded more insect genomic DNA. However, there was no significant difference between the QIAgen Blood and Tissue Kit and organic method, or the organic method and the QIAgen DNA Investigator Kit.https://scholarscompass.vcu.edu/uresposters/1464/thumbnail.jp

Temporal and Spatial Impact of Human Cadaver Decomposition on Soil Bacterial and Arthropod Community Structure and Function

As vertebrate carrion decomposes, there is a release of nutrient-rich fluids into theunderlying soil, which can impact associated biological community structure andfunction. How these changes alter soil biogeochemical cycles is relatively unknown and may prove useful in the identification of carrion decomposition islands that have long lasting, focal ecological effects. This study investigated the spatial (0, 1, and 5 m) and temporal (3–732 days) dynamics of human cadaver decomposition on soil bacterial and arthropod community structure and microbial function. We observed strong evidence of a predictable response to cadaver decomposition that varies over space for soil bacterial and arthropod community structure, carbon (C) mineralization and microbial substrate utilization patterns. In the presence of a cadaver (i.e., 0 m samples), the relative abundance of Bacteroidetes and Firmicutes was greater, while the relative abundance of Acidobacteria, Chloroflexi, Gemmatimonadetes, and Verrucomicrobia was lower when compared to samples at 1 and 5 m. Micro-arthropods were more abundant (15 to 17-fold) in soils collected at 0 m compared to either 1 or 5 m, but overall, micro-arthropod community composition was unrelated to either bacterial community composition or function. Bacterial community structure and microbial function also exhibited temporal relationships, whereas arthropod community structure did not. Cumulative precipitation was more effective in predicting temporal variations in bacterial abundance and microbial activity than accumulated degree days. In the presence of the cadaver (i.e., 0 m samples), the relative abundance of Actinobacteria increased significantly with cumulative precipitation. Furthermore, soil bacterial communities and C mineralization were sensitive to the introduction of human cadavers as they diverged from baseline levels and did not recover completely in approximately 2 years. These data are valuable for understanding ecosystem function surrounding carrion decomposition islands and can be applicable to environmental bio-monitoring and forensic sciences

A metagenomic assessment of the bacteria associated with Lucilia sericata and Lucilia cuprina (Diptera: Calliphoridae)

Lucilia Robineau-Desvoidy (Diptera: Calliphoridae) is a blow fly genus of forensic, medical, veterinary, and agricultural importance. This genus is also famous because of its beneficial uses in maggot debridement therapy (MDT). Although the genus is of considerable economic importance, our knowledge about microbes associated with these flies and how these bacteria are horizontally and trans-generationally transmitted is limited. In this study, we characterized bacteria associated with different life stages of Lucilia sericata (Meigen) and Lucilia cuprina(Wiedemann) and in the salivary gland of L. sericata by using 16S rDNA 454 pyrosequencing. Bacteria associated with the salivary gland of L. sericata were also characterized using light and transmission electron microscopy (TEM). Results from this study suggest that the majority of bacteria associated with these flies belong to phyla Proteobacteria, Firmicutes, andBacteroidetes, and most bacteria are maintained intragenerationally, with a considerable degree of turnover from generation to generation. In both species, second-generation eggs exhibited the highest bacterial phylum diversity (20 % genetic distance) than other life stages. The Lucilia sister species shared the majority of their classified genera. Of the shared bacterial genera, Providencia, Ignatzschineria, Lactobacillus, Lactococcus, Vagococcus, Morganella, and Myroides were present at relatively high abundances. Lactobacillus, Proteus,Diaphorobacter, and Morganella were the dominant bacterial genera associated with a survey of the salivary gland of L. sericata. TEM analysis showed a sparse distribution of both Gram-positive and Gram-negative bacteria in the salivary gland of L. sericata. There was more evidence for horizontal transmission of bacteria than there was for trans-generational inheritance. Several pathogenic genera were either amplified or reduced by the larval feeding on decomposing liver as a resource. Overall, this study provides information on bacterial communities associated with different life stages of Lucilia and their horizontal and trans-generational transmission, which may help in the development of better vector-borne disease management and MDT methods

Bacteria Mediate Oviposition by the Black Soldier Fly, \u3ci\u3eHermetia illucens\u3c/i\u3e (L.), (Diptera: Stratiomyidae)

Articl

Bacteria Mediate Oviposition by the Black Soldier Fly, Hermetia illucens (L.), (Diptera: Stratiomyidae)

There can be substantial negative consequences for insects colonizing a resource in the presence of competitors. We hypothesized that bacteria, associated with an oviposition resource and the insect eggs deposited on that resource, serve as a mechanism regulating subsequent insect attraction, colonization, and potentially succession of insect species. We isolated and identified bacterial species associated with insects associated with vertebrate carrion and used these bacteria to measure their influence on the oviposition preference of adult black soldier flies which utilizes animal carcasses and is an important species in waste management and forensics. We also ascertained that utilizing a mixture of bacteria, rather than a single species, differentially influenced behavioral responses of the flies, as did bacterial concentration and the species of fly from which the bacteria originated. These studies provide insight into interkingdom interactions commonly occurring during decomposition, but not commonly studied

Adult Alphitobius diaperinus Microbial Community during Broiler Production and in Spent Litter after Stockpiling

The facilities used to raise broiler chickens are often infested with litter beetles (lesser mealworm, Alphitobius diaperinus). These beetles have been studied for their carriage of pathogenic microbes; however, a more comprehensive microbiome study on these arthropods is lacking. This study investigated their microbial community in a longitudinal study throughout 2.5 years of poultry production and after the spent litter, containing the mealworms, was piled in pastureland for use as fertilizer. The mean most abundant phyla harbored by the beetles in house were the Proteobacteria (39.8%), then Firmicutes (30.8%), Actinobacteria (21.1%), Tenericutes (5.1%), and Bacteroidetes (1.6%). The community showed a modest decrease in Firmicutes and increase in Proteobacteria over successive flock rotations. The beetles were relocated within the spent litter to pastureland, where they were found at least 19 weeks later. Over time in the pastureland, their microbial profile underwent a large decrease in the percent of Firmicutes (20.5%). The lesser mealworm showed an ability to survive long-term in the open environment within the spent litter, where their microbiome should be further assessed to both reduce the risk of transferring harmful bacteria, as well as to enhance their contribution when the litter is used as a fertilizer

Temporal and Spatial Impact of Human Cadaver Decomposition on Soil Bacterial and Arthropod Community Structure and Function

As vertebrate carrion decomposes, there is a release of nutrient-rich fluids into the underlying soil, which can impact associated biological community structure and function. How these changes alter soil biogeochemical cycles is relatively unknown and may prove useful in the identification of carrion decomposition islands that have long lasting, focal ecological effects. This study investigated the spatial (0, 1, and 5 m) and temporal (3–732 days) dynamics of human cadaver decomposition on soil bacterial and arthropod community structure and microbial function. We observed strong evidence of a predictable response to cadaver decomposition that varies over space for soil bacterial and arthropod community structure, carbon (C) mineralization and microbial substrate utilization patterns. In the presence of a cadaver (i.e., 0 m samples), the relative abundance of Bacteroidetes and Firmicutes was greater, while the relative abundance of Acidobacteria, Chloroflexi, Gemmatimonadetes, and Verrucomicrobia was lower when compared to samples at 1 and 5 m. Micro-arthropods were more abundant (15 to 17-fold) in soils collected at 0 m compared to either 1 or 5 m, but overall, micro-arthropod community composition was unrelated to either bacterial community composition or function. Bacterial community structure and microbial function also exhibited temporal relationships, whereas arthropod community structure did not. Cumulative precipitation was more effective in predicting temporal variations in bacterial abundance and microbial activity than accumulated degree days. In the presence of the cadaver (i.e., 0 m samples), the relative abundance of Actinobacteria increased significantly with cumulative precipitation. Furthermore, soil bacterial communities and C mineralization were sensitive to the introduction of human cadavers as they diverged from baseline levels and did not recover completely in approximately 2 years. These data are valuable for understanding ecosystem function surrounding carrion decomposition islands and can be applicable to environmental bio-monitoring and forensic sciences