Preliminary assessment of cephalopharyngeal skeleton length and body length of Hemipyrellia ligurriens (Wiedemann) (Diptera: Calliphoridae) larvae as potential parameters to estimate minimum post mortem interval

Abstract

Entomological evidence can be utilized in forensic investigation to estimate the elapsed time after death or minimum post mortem interval estimation (PMI min ). This estimation is based on the age of dipterous specimens feeding on decomposing human tissues, which commonly refers to their larval body length. The objective of this research was to look for alternatives to larval body length which could be impaired by specimen handling and subsequently causing inaccuracy in PMI min estimation. In this research, development of forensic blow fly, Hemipyrellia ligurriens (Wiedemann) (Diptera: Calliphoridae), based on larval cephalopharyngeal skeleton length, was described for the first time. Development of H. ligurriens was represented by body length and cephalopharyngeal skeleton consisting anterodorsal process to dorsal cornu (ADP-DC), anterodorsal process to ventral cornu (ADP-VC) and dorsal cornu to ventral cornu (DC-VC). The cephalopharyngeal skeletons proportionally developed with larval body development, but periods of plateau existed between 0 and 10 h and 24-30 h, suggesting ecdysis periods of larvae. Data measurements were more consistent in cephalopharyngeal skeleton length than in larval body length, and there were strong positive significant correlations, r > 0.85 (p < 0.05). These findings warranted further investigations to examine cephalopharyngeal skeleton as an alternative growth parameter to larval body length.

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

“…Recent publications on forensically important insect larvae have addressed aspects of larval preservation and measurement [ 29 , 43 , 48 , 49 ]. However, standard measurements or a metrological framework for standard criteria to select features for such measurement have not been established, despite recent concern [ 50 ].…”

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

“…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).…”

“…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).…”

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

“…The transformation of cephalopharyngeal skeleton could be presented in growth trajectory to estimate larval age for PMI min analysis based on centroid size. In contrast with its body length, the measurement based on cephalopharyngeal skeleton morphometry was more reliable and consistent to be used as growth parameter in forensic entomology (Rabbani and Zuha 2017;Eliza and Zuha 2018). In addition, these changes explained by the ontogenetic allometry in C. megacephala larva were represented by the cephalopharyngeal skeleton.…”

“…However, there were drawbacks when using larval body length because it can be affected by specimens handling (Tantawi and Greenberg 1993;Adams and Hall 2003;Day and Wallman 2008;Richards et al 2013) and subsequently lead to inaccuracies in mPMI estimation. Therefore, previous researches suggested cephalopharyngeal skeleton as an alternative growth parameter to larval body length because of its measurement consistency and positive allometry with larval body length (Eliza and Zuha 2018;Rabbani and Zuha 2017). In Calliphoridae larvae, cephalopharyngeal skeleton is the invaginating mouthparts in the cephalic region of the larva, consisting of pharyngeal sclerites and mandibles which are used to facilitate food intake (Teskey 1981).…”