Chrysomya megacephala (Fabricius, 1794) (Diptera: Calliphoridae) development by landmark-based geometric morphometrics of cephalopharyngeal skeleton: a preliminary assessment for forensic entomology application

Sim, Li Xuan; Zuha, Raja Muhammad

doi:10.1186/s41935-019-0158-y

Cited by 6 publications

(10 citation statements)

References 43 publications

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“…However, typically, they do not drastically differ between instars within a species, which makes quantitative measures of maturity necessary. The shape or colour of a feature can be quantitatively described by morphometrics [ 33 , 34 ] or spectrometry, respectively. Pupal development does not progress through discrete stages, but the development of certain features (such as seta formation or setal pigmentation) can be treated as discrete developmental landmarks at sufficiently coarse time scales and continuous developmental processes at finer temporal resolutions [ 3 ].…”

Section: Introductionmentioning

confidence: 99%

Metrological framework for selecting morphological characters to identify species and estimate developmental maturity of forensically significant insect specimens

Midgley

Villet

2020

Forensic Sciences Research

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Accurate age estimates of immature necrophagous insects associated with a human or animal body can provide evidence of how long the body has been dead. These estimates are based on species-specific details of the insects’ aging processes, and therefore require accurate species identification and developmental stage estimation. Many professionals who produce or use identified organisms as forensic evidence have little training in taxonomy or metrology, and appreciate the availability of formalized principles and standards for biological identification. Taxonomic identifications are usually most readily and economically made using categorical and qualitative morphological characters, but it may be necessary to use less convenient and potentially more ambiguous characters that are continuous and quantitative if two candidate species are closely related, or if identifying developmental stages within a species. Characters should be selected by criteria such as taxonomic specificity and metrological repeatability and relative error . We propose such a hierarchical framework, critique various measurements of immature insects, and suggest some standard approaches to determine the reliability of organismal identifications and measurements in estimating postmortem intervals. Relevant criteria for good characters include high repeatability (including low scope for ambiguity or parallax effects), pronounced discreteness, and small relative error in measurements. These same principles apply to individuation of unique objects in general. Key points Metrological rigour can increase in forensic entomology by selecting measurements based on their metrological qualities. Selection of high-quality features for morphological identification of organisms should consider these criteria: (1) pronounced discreteness of features (minimising group overlap or maximizing interval); (2) high repeatability of assessment (such as symmetrical width rather than asymmetrical length); (3) small relative error in measurement (selecting the physically largest continuous rigid feature for measurement). These metrological principles also apply to individuation of unique objects in general.

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Section: Introductionmentioning

confidence: 99%

Metrological framework for selecting morphological characters to identify species and estimate developmental maturity of forensically significant insect specimens

Midgley

Villet

2020

Forensic Sciences Research

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“…Recent work on the application of geometric morphometrics to wing shape analysis of species from the Sarcophagidae and the Calliphoridae family showed that wing shape variation was reliable for classifying Chrysomya species [37] and even distinguishing between sexes of the same species [38]. Further application to cephalopharyngeal skeleton shape of fly larvae is also possible [39,40].…”

Section: Introductionmentioning

confidence: 99%

Random forests for predicting species identity of forensically important blow flies (Diptera: Calliphoridae) and flesh flies (Diptera: Sarcophagidae) using geometric morphometric data: Proof of concept

Khang

Puaad

Teh

et al. 2021

Journal of Forensic Sciences

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Wing shape variation has been shown to be useful for delineating forensically important fly species in two Diptera families: Calliphoridae and Sarcophagidae. Compared to DNA-based identification, the cost of geometric morphometric data acquisition and analysis is relatively much lower because the tools required are basic, and stable softwares are available. However, to date, an explicit demonstration of using wing geometric morphometric data for species identity prediction in these two families remains lacking. Here, geometric morphometric data from 19 homologous landmarks on the left wing of males from seven species of Calliphoridae (n = 55), and eight species of Sarcophagidae (n = 40) were obtained and processed using Generalized Procrustes Analysis. Allometric effect was removed by regressing centroid size (in log 10 ) against the Procrustes coordinates. Subsequently, principal component analysis of the allometry-adjusted Procrustes variables was done, with the first 15 principal components used to train a random forests model for species prediction. Using a real test sample consisting of 33 male fly specimens collected around a human corpse at a crime scene, the estimated percentage of concordance between species identities predicted using the random forests model and those inferred using DNA-based identification was about 80.6% (approximate 95% confidence interval = [68.9%, 92.2%]). In contrast, baseline concordance using naive majority class prediction was 36.4%. The results provide proof of concept that geometric morphometric data has good potential to complement morphological and DNA-based identification of blow flies and flesh flies in forensic work.

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“…Studying the efficacy of the cephalopharyngeal skeleton as a growth parameter is therefore necessary as in the later studies recorded it grew proportionally with larval body size during active feeding stage (Eliza & Zuha, 2018;Sim & Zuha, 2019). The current study compared the effect of hot water and direct killing by immersion in 70% ethanol on the cephalopharyngeal skeleton and total body size of third instar Chrysomya megacephala (Fabricius, 1786) larvae, a forensically important blowfly in Malaysia, Thailand, and the rest of the world (Lee et al, 2004;Sukontason et al, 2008;Thevan et al, 2010;Badenhorst & Villet, 2018).…”

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confidence: 99%

“…The internal tissues surrounding the cephalopharyngeal skeleton were carefully removed in 10% KOH and subsequently transferred into 10% acetic acid for 10 min. Cephalopharyngeal skeleton was then soaked in 70% ethanol for 20 min before they were mounted onto a glass slide in lateral position using Berlese fluid and covered by a 6 mm round coverslip (Sim & Zuha, 2019). Measurements of the cephalopharyngeal skeleton were conducted immediately after the mounting process based on inter landmark distances between anterodorsal process (tip of the dorsal bridge) to dorsal cornu (ADP-DC), the anterodorsal process to ventral cornu (ADP-VC), and dorsal cornu to ventral cornu (DC-VC) (Nateeworanart et al, 2010;Nuñez & Liria, 2016;Rabbani & Zuha, 2017) (Figure 1).…”

mentioning

confidence: 99%

“…Most importantly, results from the current study suggesting that cephalopharyngeal skeletons can be used as an alternative growth parameter to estimate larval age after larval body length was found to be affected by various practical factors. For example, Sim & Zuha (2019) showed that the cephalopharyngeal skeleton size of C. megacephala had a linear growth pattern during the active feeding period. Likewise, in other calliphorid species, the cephalopharyngeal skeleton could show positive trajectories throughout larval development as observed in H. violacea (Rabbani & Zuha, 2017) and Hemipyrellia ligurriens (Wiedemann, 1830) (Eliza & Zuha, 2018).…”

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confidence: 99%

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CEPHALOPHARYNGEAL SKELETONS OF Chrysomya megacephala (Fabricius, 1794) (DIPTERA: CALLIPHORIDAE) THIRD INSTAR LARVAE DISPLAYED RESISTANCE TO HOT-WATER KILLING METHOD – IMPLICATIONS IN FORENSIC ENTOMOLOGY PRACTICE

ABDULLAH¹,

Zuha²

2020

MABJ

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Chrysomya megacephala (Fabricius, 1794) (Diptera: Calliphoridae) development by landmark-based geometric morphometrics of cephalopharyngeal skeleton: a preliminary assessment for forensic entomology application

Cited by 6 publications

References 43 publications

Metrological framework for selecting morphological characters to identify species and estimate developmental maturity of forensically significant insect specimens

Metrological framework for selecting morphological characters to identify species and estimate developmental maturity of forensically significant insect specimens

Random forests for predicting species identity of forensically important blow flies (Diptera: Calliphoridae) and flesh flies (Diptera: Sarcophagidae) using geometric morphometric data: Proof of concept

CEPHALOPHARYNGEAL SKELETONS OF Chrysomya megacephala (Fabricius, 1794) (DIPTERA: CALLIPHORIDAE) THIRD INSTAR LARVAE DISPLAYED RESISTANCE TO HOT-WATER KILLING METHOD – IMPLICATIONS IN FORENSIC ENTOMOLOGY PRACTICE

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