Author
Ian R. Dadour
Other affiliations: University of Western Australia, Murdoch University
Bio: Ian R. Dadour is an academic researcher from Boston University. The author has contributed to research in topics: Forensic entomology & Lucilia. The author has an hindex of 27, co-authored 95 publications receiving 2388 citations. Previous affiliations of Ian R. Dadour include University of Western Australia & Murdoch University.
Papers published on a yearly basis
Papers
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TL;DR: Low levels of variation between some species of the same genus however indicate that further sequencing is required to locate a region for development of a molecular-based technique for identification.
Abstract: Forensic entomology requires the fast and accurate identification of insects collected from a corpse for estimation of the postmortem interval (PMI). Identification of specimens is traditionally performed using morphological features of the insect. Morphological identification may be complicated however by the numerical diversity of species and physical similarity between different species, particularly in immature stages. In this study, sequencing was performed to study the mitochondrial DNA (mtDNA) as the prospective basis of a diagnostic technique. The sequencing focused on a section of the cytochrome oxidase I encoding region of mtDNA. Three species of calliphorid (blow flies) commonly associated with corpses in western Australia, Calliphora dubia, Chrysomya rufifacies and Lucilia sericata, in addition to specimens of Calliphora augur and Chrysomya megacephala were studied. Phylogenetic analysis of data revealed grouping of species according to genus. The DNA region sequenced allowed identification of all species, providing high support for separation on congeneric species. Low levels of variation between some species of the same genus however indicate that further sequencing is required to locate a region for development of a molecular-based technique for identification.
145 citations
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TL;DR: The results suggest that the subadult mandible is not dimorphic (to the extent that dimorphism is not evident within the sample the authors studied); thus, sex determination using previously described criteria is likely to yield poor results.
Abstract: There have been numerous attempts, with varying degrees of success, to differentiate males from females on the basis of the immature skeleton. We investigate here whether the mandible can discriminate immature individuals by sex; the techniques we apply are from the field of geometric morphometrics. The application of these methods in forensic anthropology is still relatively new; thus, an important aspect of this research is that it demonstrates potential applications in this discipline. The sample comprises 96 known age and sex subadult individuals; the three-dimensional coordinates of 38 landmarks are analyzed using the shape analysis software morphologika. Multivariate regressions indicated no significant sexual dimorphism in the subadult sample; this result is supported by poor cross-validated classification accuracy (59%). Our results suggest that the subadult mandible is not dimorphic (to the extent that dimorphism is not evident within the sample we studied); thus, sex determination using previously described criteria is likely to yield poor results.
125 citations
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01 Jan 1989-Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology
TL;DR: It was concluded that the precise alternating pattern between two males is significantly affected by noise and a strong masking effect by biological noise on the perception of the conspecific signal within the afferent auditory pathway is revealed.
Abstract: Summary1.Hemisaga denticulata andMygalopsis marki are two sympatrically occurring species of bushcricket. Both also have almost complete overlap in their song frequencies (Fig. 2). However, the temporal pattern of their respective songs differs considerably, males ofM. marki sing continuously compared with short bursts of song produced by males ofH. denticulata. A comparative study between two populations ofH. denticulata showed that in the presence of singing males ofM. marki, the song ofH. denticulata was suppressed (Fig. 5, Table 1). Furthermore, song interference was also demonstrated neurophysiologically in the field using the response of the omega-neuron as a ‘biological microphone’ (Fig. 4).2.In aggregations ofH. denticulata males alternate their chirp pattern, and this behaviour was used as an assay in the laboratory to test the susceptibility of intraspecific communication to biological noise. It was concluded that the precise alternating pattern between two males is significantly affected by noise (Fig. 6).3.Neurophysiological experiments performed in the laboratory revealed a strong masking effect by biological noise on the perception of the conspecific signal within the afferent auditory pathway (Figs. 7, 8). This experiment when conducted in the field exhibited similar masked responses in the omega-neuron (Figs. 9, 10).
110 citations
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TL;DR: This region appears to provide southern African forensic entomologists with a new technique for providing accurate identification for application to post‐mortem interval (PMI) estimation.
Abstract: One major aspect of research in forensic entomology is the investigation of molecular techniques for the accurate identification of insects. Studies to date have addressed the corpse fauna of many geographical regions, but generally neglected the southern African calliphorid species. In this study, forensically significant calliphorids from South Africa, Swaziland, Botswana and Zimbabwe and Australia were sequenced over an 1167 base pair region of the COI gene. Phylogenetic analysis was performed to examine the ability of the region to resolve species identities and taxonomic relationships between species. Analyses by neighbour-joining, maximum parsimony and maximum likelihood methods all showed the potential of this region to provide the necessary species-level identifications for application to post-mortem interval (PMI) estimation; however, higher level taxonomic relationships did vary according to method of analysis. Intraspecific variation was also considered in relation to determining suitable maximum levels of variation to be expected during analysis. Individuals of some species in the study represented populations from both South Africa and the east coast of Australia, yet maximum intraspecific variation over this gene region was calculated at 0.8%, with minimum interspecific variation at 3%, indicating distinct ranges of variation to be expected at intra- and interspecific levels. This region therefore appears to provide southern African forensic entomologists with a new technique for providing accurate identification for application to estimation of PMI.
103 citations
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TL;DR: This study used phylogenetic analysis to assess the species status of 27 forensically important calliphorid species based on 1167 base pairs of the COI gene of 119 specimens from 22 countries, and confirmed the utility of theCOI gene in identifying most species.
Abstract: A proliferation of molecular studies of the forensically significant Calliphoridae in the last decade has seen molecule-based identification of immature and damaged specimens become a routine complement to traditional morphological identification as a preliminary to the accurate estimation of post-mortem intervals (PMI), which depends on the use of species-specific developmental data Published molecular studies have tended to focus on generating data for geographically localised communities of species of importance, which has limited the consideration of intraspecific variation in species of global distribution This study used phylogenetic analysis to assess the species status of 27 forensically important calliphorid species based on 1167 base pairs of the COI gene of 119 specimens from 22 countries, and confirmed the utility of the COI gene in identifying most species The species Lucilia cuprina, Chrysomya megacephala, Ch saffranea, Ch albifrontalis and Calliphora stygia were unable to be monophyletically resolved based on these data Identification of phylogenetically young species will require a faster-evolving molecular marker, but most species could be unambiguously characterised by sampling relatively few conspecific individuals if they were from distant localities Intraspecific geographical variation was observed within Ch rufifacies and L cuprina, and is discussed with reference to unrecognised species
102 citations
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TL;DR: The objectives of BIOS 781 are to present basic population and quantitative genetic principles, including classical genetics, chromosomal theory of inheritance, and meiotic recombination, and methods for genome-wide association and stratification control.
Abstract: LEARNING The objectives of BIOS 781 are to present: OBJECTIVES: 1. basic population and quantitative genetic principles, including classical genetics, chromosomal theory of inheritance, and meiotic recombination 2. an exposure to QTL mapping methods of complex quantitative traits and linkage methods to detect co-segregation with disease 3. methods for assessing marker-disease linkage disequilibrium, including case-control approaches 4. methods for genome-wide association and stratification control.
1,506 citations
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20 Apr 1907
TL;DR: For instance, when a dog sees another dog at a distance, it is often clear that he perceives that it is a dog in the abstract; for when he gets nearer his whole manner suddenly changes, if the other dog be a friend as discussed by the authors.
Abstract: ION, GENERAL CONCEPTIONS, SELF-CONSCIOUSNESS, MENTAL INDIVIDUALITY. It would be very difficult for any one with even much more knowledge than I possess, to determine how far animals exhibit any traces of these high mental powers. This difficulty arises from the impossibility of judging what passes through the mind of an animal; and again, the fact that writers differ to a great extent in the meaning which they attribute to the above terms, causes a further difficulty. If one may judge from various articles which have been published lately, the greatest stress seems to be laid on the supposed entire absence in animals of the power of abstraction, or of forming general concepts. But when a dog sees another dog at a distance, it is often clear that he perceives that it is a dog in the abstract; for when he gets nearer his whole manner suddenly changes, if the other dog be a friend. A recent writer remarks, that in all such cases it is a pure assumption to assert that the mental act is not essentially of the same nature in the animal as in man. If either refers what he perceives with his senses to a mental concept, then so do both. (44. Mr. Hookham, in a letter to Prof. Max Muller, in the 'Birmingham News,' May, 1873.) When I say to my terrier, in an eager voice (and I have made the trial many times), "Hi, hi, where is it?" she at once takes it as a sign that something is to be hunted, and generally first looks quickly all around, and then rushes into the nearest thicket, to scent for any game, but finding nothing, she looks up into any neighbouring tree for a squirrel. Now do not these actions clearly shew that she had in her mind a general idea or concept that some animal is to be discovered and hunted? It may be freely admitted that no animal is self-conscious, if by this term it is implied, that he reflects on such points, as whence he comes or whither he will go, or what is life and death, and so forth. But how can we feel sure that an old dog with an excellent memory and some power of imagination, as shewn by his dreams, never reflects on his past pleasures or pains in the chase? And this would be a form of self-consciousness. On the other hand, as Buchner (45. 'Conferences sur la Theorie Darwinienne,' French translat. 1869, p. 132.) has remarked, how little can the hardworked wife of a degraded Australian savage, who uses very few abstract words, and cannot count above four, exert her self-consciousness, or reflect on the nature of her own existence. It is generally admitted, that the higher animals possess memory, attention, association, and even some imagination and reason. If these powers, which differ much in different animals, are capable of improvement, there seems no great improbability in more complex faculties, such as the higher forms of abstraction, and selfconsciousness, etc., having been evolved through the development and combination of the simpler ones. It has been urged against the views here maintained that it is impossible to say at what point in the ascending scale animals become capable of abstraction, etc.; but who can say at what age this occurs in our young children? We see at least that such powers
1,464 citations
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TL;DR: This investigation revealed the presence of three species of Acanthocephala (Neoechinorhynchus pseudemydis, N. emyditoides, and N. chrysemydis) in Louisiana turtles and confirms Fisher’s (1960) work.
Abstract: Prior to the work of Cable and Hopp (J. Parasit. 40(6): 674.680, 1954) Neoechinorhynchus emydis (L e i d y, 1851) was the only recognized species of Acanthocephala in North American turtles. To date, a total of five species have been described. Of these, two species (Neoechinorbynchus pseudemydis Cable and Hopp, 1954, and N. emyditoides Fisher, 1960) were recovered from six of 12 Louisiana turtles (Pseudemys scripta elegans (Wied)) examined by Fisher (J. Parasit. 46(2): 257-266, 1960). He (1960) also found N. chrysemydis Cable and Hopp, 1954 in Pseudemys scripta subsp. The data pt .sented are results of studies conducted between the spring of 1965 and the summer of 1966. Seventynine turtles (48 female and 31 males) encompassing seven species (47 Pseudemys scripta elegans (Wied), three P. floridana hoyi (Holbrook), eight Chelydra serpentina serpentina (L.), eight Kinosternon subrubrum hippocrepis Gray, seven Terrapene carolina carolina (L.), five T. c. triunguis (Agassiz) and one Trionyx muticus (LeSueur) collected from Baton Rouge and vicinity were examined. This investigation revealed the presence of three species of Acanthocephala (Neoechinorhynchus pseudemydis, N. emyditoides, and N. chrysemydis) in Louisiana turtles and confirms Fisher’s (1960) work. Of the seven species of turtles examined, only P. s. e!egans (25 16 females and 9 males) and P. floridana hoyi (2 females) were positive with infection. Three of the 25 P. s. e!egans had mixed infection comprising three species of Neoechinorhynchus while seven had two species respectively. P. f!oridana hoyi represents a host record for N. chrysemydis;
772 citations
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TL;DR: This chapter reviews recent advancements in studies of vocal adaptations to interference by background noise and relates these to fundamental issues in sound perception in animals and humans.
Abstract: Publisher Summary Environmental noise can affect acoustic communication through limiting the broadcast area, or active space, of a signal by decreasing signal-to-noise ratios at the position of the receiver. At the same time, noise is ubiquitous in all habitats and is, therefore, likely to disturb animals, as well as humans, under many circumstances. However, both animals and humans have evolved diverse solutions to the background noise problem, and this chapter reviews recent advancements in studies of vocal adaptations to interference by background noise and relate these to fundamental issues in sound perception. The chapter starts with the discussion of sender's side by considering potential evolutionary shaping of species-specific signal characteristics and individual short‐term adjustments of signal features. Subsequently, it focuses on the receivers of signals and reviews their sensory capacities for signal detection, recognition, and discrimination and relates these issues to auditory scene analysis and the ecological concept of signal space. The data from studies on insects, anurans, birds, and mammals, including humans, and to a lesser extent available work on fish and reptiles is also discussed in the chapter.
765 citations