Browsing by Author "Moore, Hannah E."
Now showing 1 - 9 of 9
Results Per Page
Sort Options
Item Open Access 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 profilesItem Open Access Age estimation of Calliphora (Diptera: Calliphoridae) larvae using cuticular hydrocarbon analysis and Artificial Neural Networks(Elsevier, 2016-09-20) Moore, Hannah E.; Butcher, John B.; Adam, Craig D.; Day, Charles R.; Drijfhout, Falko P.Cuticular hydrocarbons were extracted daily from the larvae of two closely related blowflies Calliphora vicina and Calliphora vomitoria (Diptera: Calliphoridae). The hydrocarbons were then analysed using Gas Chromatography–Mass Spectrometry (GC–MS), with the aim of observing changes within their chemical profiles in order to determine the larval age. The hydrocarbons were examined daily for each species from 1 day old larvae until pupariation. The results show significant chemical changes occurring from the younger larvae to the post-feeding larvae. With the aid of a multivariate statistical method (Principal Component Analysis and Artificial Neural Networks), samples were clustered and classified, allowing for the larval age to be established. Results from this study allowed larvae to be aged to the day with at worst, 87% accuracy, which suggests there is great potential for the use of cuticular hydrocarbons present on larvae to give an indication of their age and hence potentially a valuable tool for minimum PMI estimations.Item Open Access Cuticular hydrocarbon analysis for the identification, ageing and geographical variations of forensically important blowflies(2022-02) Kula, Canan; Moore, Hannah E.; Drijfhout, Falko P.; Shortland, Andrew J.Calliphoridae (blowflies) are important for forensic entomology as they are often the first group of insects to inhabit decomposing remains. To estimate the minimum post-mortem interval (PMImin), blowfly samples are collected from the crime scene and identified, and then the age needs to be determined for each species. Accurate species identification is crucial, as varied species have different life-stage timings. Previous studies on Diptera have shown the possibility of using cuticular hydrocarbon (CHC) analysis to aid species identification, ageing and ultimately calculating PMImin. However, since prior research was conducted at constant temperatures, the effect of fluctuating temperature on chemical profiles and the stability of CHCs in the field remains unclear. This thesis aims to examine the CHC profiles of Lucilia sericata and Calliphora vicina reared outdoors in the United Kingdom, Germany and Turkey in terms of species, age and inter-population differences. The first study investigates whether the stability of the CHC profiles of two colonies reared outdoors can be used to identify species-specific characteristics. The second examines the effects of fluctuating and constant temperatures on the CHC profiles of the life cycle stages and the use of their chemical profiles for age estimations. The final study aims to determine the differences in CHC profiles of the same species living in different habitats and whether they can be used to distinguish populations. The CHC profiles of the samples were extracted and analysed using Gas Chromatography-Mass Spectrometry (GC-MS). The statistical interpretation was carried out using Principal Component Analysis (PCA). The results showed that CHC profiles differed significantly between developmental stages by species, age, rearing temperature and geographical location. This study highlights that despite environmental factors affecting the stability of CHC compositions, the CHC analysis can be used as a complementary tool for identifying and ageing the species. Furthermore, the effects of ambient temperature and geographical variation on CHC profiles may be useful for determining inter-population variations.Item Open Access 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.Item Open Access 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, DanielThe 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.Item Open Access Forensic Toxicology in Embalmed Human Remains(2021-04) Lloyd, Richard G C; Harrison, Karl; Moore, Hannah E.; Mai, NathalieWithin the human body, vitreous humour, cerebrospinal fluid and synovial fluid are all contained within anatomical compartments that, by virtue of their relative avascularity, provide considerable protection from contamination during the embalming process. Analysing samples taken from embalmed medical school cadavers, and using an entirely novel headspace GC/MS method, the concentration of formaldehyde in all three fluids is shown to be significantly less than has previously been assumed in the literature. Using a newly-developed LC/Q-ToF method, the stability of fifteen drugs of forensic interest in representative concentrations of formaldehyde is then reported. The study is prompted by the fact that United Kingdom nationals are dying abroad with increasing frequency. Following repatriation of their bodies, an autopsy may be undertaken before permission for a funeral is granted. Although toxicological screening may form an important part of the investigative processes, there exists a large degree of uncertainty surrounding the reactive nature of formaldehyde, the main constituent of embalming fluids, with substances commonly implicated in drug-related deaths. It is the case, therefore, that in repatriated bodies, all of which are routinely embalmed before leaving the country in which death occurred, the presence of formaldehyde can cause significant problems for the forensic toxicologist. Although a number of papers in the past twenty years have investigated the challenges of drug detection in embalmed tissues, they have largely examined the problem from the perspective of histological samples preserved in formalin. While some of this work has, by implication, considered the analysis of samples taken from embalmed bodies, no studies have addressed directly the specific problems arising in the toxicological analysis of embalmed and repatriated bodies. The studies reported within the thesis demonstrate that there is considerable merit in undertaking further work on the usefulness of these fluids in the toxicological analysis of embalmed and repatriated nationalsItem Open Access 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.Item Open Access Juvenile hormone: production, regulation, current application in vector control and its future applications(Malaysian Society of Parasitology and Tropical Medicine, 2021-07-31) Nur Aliah, N. A.; Ab-Rahim, S.; Moore, Hannah E.; Heo, C. C.Juvenile hormone is an exclusive hormone found in insects which involves regulating various insect physiology. A total of eight juvenile hormones have been identified in insects which include JH 0, JH I, JH II, JH III, 4-methyl JH I (Iso- JH 0), JHB III, JHSB III, and MF. Corpora allata are the glands responsible for the production and synthesis of these hormones. They are involved in moulting, reproduction, polyethism, and behavioural regulations in different orders of insects. Factors such as diet temperatures, photoperiods, and plant compounds affect the biosynthesis and regulation of juvenile hormones. Juvenile hormones analogue is usually used to disrupt normal regulation of JH and this analogue is categorized as insect-growth regulators (IGRs) and is widely used in pest control as an alternative to chemical insecticides. Other applications of biosynthesis activities of this hormone have not been explored in the area of JHs. In this review, current applications of JHs and with an addition of their application will be discussed.Item Open Access 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.