Browsing by Author "Moore, Hannah E."

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    Adult fly age estimations using cuticular hydrocarbons and Artificial Neural Networks in forensically important Calliphoridae species
    (Elsevier, 2017-10-08) Moore, Hannah E.; Butcher, John B.; Day, Charles R.; Drijfhout, Falko P.
    Blowflies (Diptera: Calliphoridae) are forensically important as they are known to be one of the first to colonise human remains. The larval stage is typically used to assist a forensic entomologists with adult flies rarely used as they are difficult to age because they remain morphologically similar once they have gone through the initial transformation upon hatching. However, being able to age them is of interest and importance within the field. This study examined the cuticular hydrocarbons (CHC) of Diptera: Calliphoridae species Lucilia sericata, Calliphora vicina and Calliphora vomitoria. The CHSs were extracted from the cuticles of adult flies and analysed using Gas Chromatography-Mass Spectrometry (GC-MS). The chemical profiles were examined for the two Calliphora species at intervals of day 1, 5, 10, 20 and 30 and up to day 10 for L. sericata. The results show significant chemical changes occurring between the immature and mature adult flies over the extraction period examined in this study. With the aid of a Principal Component Analysis (PCA) and Artificial Neural Networks (ANN), samples were seen to cluster, allowing for the age to be established within the aforementioned time frames. The use of ANNs allowed for the automatic classification of novel samples with very good performance. This was a proof of concept study, which developed a method allowing to age post-emergence adults by using their chemical profiles
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    Cuticular hydrocarbon analysis in forensic entomology: a review
    (Equinox Publishing, 2017-04-30) Moore, Hannah E.
    Blowflies are the first inhabitants of decomposing remains and are therefore of forensic relevance for post mortem interval estimations. Forensic entomology is becoming widely accepted as a branch of forensic science and is being utilised more within forensic casework. This wider use has driven an increase in research being carried out within the field, in particular, in less “classical” techniques such as DNA and chemical analysis in the form of cuticular hydrocarbon analysis. This short review will examine the research currently being studied in the area of cuticular hydrocarbon analysis of forensically important Diptera for species identification and ageing.
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    Cuticular hydrocarbons for identifying Sarcophagidae (Diptera)
    (Nature Publishing Group, 2021-04-08) Moore, Hannah E.; Hall, Martin J. R.; Drijfhout, Falko P.; Cody, Robert B.; Whitmore, Daniel
    The composition and quantity of insect cuticular hydrocarbons (CHCs) can be species-specific as well as sexually dimorphic within species. CHC analysis has been previously used for identification and ageing purposes for several insect orders including true flies (Diptera). Here, we analysed the CHC chemical profiles of adult males and females of eleven species of flesh flies belonging to the genus Sarcophaga Meigen (Sarcophagidae), namely Sarcophaga africa (Wiedemann), S. agnata Rondani, S. argyrostoma Robineau-Desvoidy, S. carnaria (Linnaeus), S. crassipalpis Macquart, S. melanura Meigen, S. pumila Meigen, S. teretirostris Pandellé, S. subvicina Rohdendorf, S. vagans Meigen and S. variegata (Scopoli). Cuticular hydrocarbons extracted from pinned specimens from the collections of the Natural History Museum, London using a customised extraction technique were analysed using Gas Chromatography–Mass Spectrometry. Time of preservation prior to extraction ranged between a few weeks to over one hundred years. CHC profiles (1) allowed reliable identification of a large majority of specimens, (2) differed between males and females of the same species, (3) reliably associated males and females of the same species, provided sufficient replicates (up to 10) of each sex were analysed, and (4) identified specimens preserved for up to over one hundred years prior to extraction.
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    Geographical variation of cuticular hydrocarbon profiles of adult flies and empty puparia amongst three populations of Calliphora vicina (Diptera: Calliphoridae)
    (Oxford University Press, 2022-11-14) Kula, Canan; Amendt, Jens; Drijfhout, Falko P.; Moore, Hannah E.
    Blowflies (Diptera: Calliphoridae) are of great importance in forensic entomology and in determining the minimum post-mortem interval, as they may be the first group of insects to colonise decomposing remains. Reliable species identification is an essential prerequisite. Classically, morphological characters or DNA sequences are used for this purpose. However, depending on the species and the condition of the specimen, this can be difficult, e.g. in the case of empty fly puparia. Recent studies have shown that cuticular hydrocarbon (CHC) profiles are species-specific in necrophagous taxa and represent another promising tool for identification. However, the population-specific variability of these substances as a function of e.g. local climatic parameters has not yet been sufficiently investigated. The aim of this study was to determine the geographical variation of CHC profiles of the blowfly Calliphora vicina depending on different countries of origin. Flies were reared in the UK, Germany and Turkey in common garden experiments under ambient conditions. CHC profiles of the resulting adult flies and their empty puparia were analysed using gas chromatography-mass spectrometry. Data were visualised by principal component analysis and clustered by population. The populations of the UK and Germany, both having similar climates and being geographically close to each other, showed greater similarities in CHC profiles. However, the CHC profile of the Turkish population, whose climate is significantly different from the other two populations, was very different. Our study confirms the high potential of CHC analysis in forensic entomology but highlights the need to investigate geographical variability in chemical profiles.
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    The potential use of cuticular hydrocarbons and multivariate analysis to age empty puparial cases of Calliphora vicina and Lucilia sericata
    (Nature, 2017-05-16) Moore, Hannah E.; Perchal, Jennifer L.; Benbow, M. Eric; Drijfhout, Falko P.
    Cuticular hydrocarbons (CHC) have been successfully used in the field of forensic entomology for identifying and ageing forensically important blowfly species, primarily in the larval stages. However in older scenes where all other entomological evidence is no longer present, Calliphoridae puparial cases can often be all that remains and therefore being able to establish the age could give an indication of the PMI. This paper examined the CHCs present in the lipid wax layer of insects, to determine the age of the cases over a period of nine months. The two forensically important species examined were Calliphora vicina and Lucilia sericata. The hydrocarbons were chemically extracted and analysed using Gas Chromatography – Mass Spectrometry. Statistical analysis was then applied in the form of nonmetric multidimensional scaling analysis (NMDS), permutational multivariate analysis of variance (PERMANOVA) and random forest models. This study was successful in determining age differences within the empty cases, which to date, has not been establish by any other technique.