Effect of Cadmium Chloride on the Development of Chrysomya Megacephala (Diptera:Calliphoridae) and its Importance to Postmortem Interval Estimate

Abstract

Cadmium chloride is one of the highly toxic compounds among the heavy metals. It exerts a negative impact on the living organisms and accumulates in food chain and could lead to some serious problems, such as high rate of mortality, lower longevity, decreased fecundity and lower hatching ability of many insects and other arthropods. The present work dealt with the evaluation of cadmium chloride because there is lack of published entomotoxicological reports for cadmium chloride have evaluated their effect on the growth and development of this forensically important fly blow fly species, Chrysomya megacephala (Diptera: Calliphoridae). Larvae of Chrysomya megacephala (Diptera: Calliphoridae) reared on rat tissues that were previously exposed to Cadmium chloride (CdCl2) in different concentrations: Half lethal (3.25mg/kg bw), Lethal (6.5 mg/ kg bw) and Twice Lethal (13 mg/kg bw) by intraperitoneal injection (i.p.). Development rate, larval body length, width, weight, pupal and adult weight and mortality were the observed parameters. Results demonstrated that the development rate of larvae between treated group and control group varied significantly. Development took longer time in the presence of high Cadmium concentration compared to control. Mortality results indicated greater mortality among the larvae with increased cadmium concentration as compared to control. It can be concluded that Cadmium chloride has negative effect on all the life stages of Chrysomya megacephala. Since cadmium chloride alters the rate of development in Chrysomya megacephala. There are chances of miscalculation of PMI if the presence of cadmium chloride is not taken into consideration. For example there could be wrong estimation of PMI by up to 18-86 hours if age of larvae is determined on the basis of its length ignoring the effect of cadmium chloride.

A review on the effects of heavy metals on the development of blow flies (Diptera: Calliphoridae)

“…Researchers used a variety of food sources spiked with heavy metals to rear immatures; all food sources are shown in Figure 1. The most common were rats (Heer & Singh, 2019;Kaur, 2016;Singh & Bhupinderjit, 2017) injected with different concentrations of heavy metals, and artificial diets (Bessa et al, 2021;Moe et al, 2001;Simkiss et al, 1993). Additionally, ground beef (Al-Misned, 2001, 2003, chicken liver (Kökdener et al, 2022;Kökdener & Yılmaz, 2021), and pork liver (Malejko et al, 2020;Shulman et al, 2017) were used.…”

“…There is a consensus among the different articles that the mortality rate of both larvae and pupae of all species increased as the concentration of these heavy metals increased. Generally, larval mortality was higher than pupal mortality (Al-Misned, 2001;Heer & Singh, 2019;Singh & Bhupinderjit, 2017). Kaur (2016) found that for higher concentrations of cadmium chloride, mercuric chloride, lead acetate, and arsenic trioxide both larval and pupal mortality of C. megacephala increased; however, for the lower concentration of arsenic trioxide, there was a lower larval mortality.…”

“…The majority of the results show that larval, pupal and adult weight is affected by different concentrations of heavy metals, regardless of the species. Larval and pupal weight decreased as cadmium (Malejko et al, 2020;Moe et al, 2001), thallium (Malejko et al, 2020) lead acetate (Heer & Singh, 2019;Kaur, 2016), cadmium chloride (Kaur, 2016;Singh & Bhupinderjit, 2017), copper chloride and zinc chloride (Kökdener et al, 2022), and mercuric chloride and arsenic trioxide (Kaur, 2016) concentrations increased for L. sericata and C. megacephala. In their gunshot residue (GSR) study, Kökdener and Yılmaz (2021) found that both L. sericata pupal and adult weights were similar across antimony and lead concentrations (but still lower than the control group), while they were significantly lower for all barium concentrations.…”

“…4.4.1 | Thallium, lead acetate, cadmium, cadmium chloride, mercury, mercuric chloride, barium, antimony, copper chloride Body length was the third dependent variable discussed in literature. The time needed to reach maximum larval length was directly proportional to the concentration of these heavy metals (Heer & Singh, 2019;Kaur, 2016;Malejko et al, 2020;Singh & Bhupinderjit, 2017) for L. sericata and C. megacephala. In general, all larval and pupal length and width were smaller in flies exposed to metals than in the control groups.…”

“…The presence of heavy metals can cause a decrease in body mass as they may reduce food intake (e.g., morphological deformities of the mouthparts) and absorption (Bayley et al, 1995;Servia et al, 2006); moreover, they can decrease the production of growth hormones and gene expression which can result in decreased lipid storage and thus body mass (Heer & Singh, 2019;Ilahi et al, 2020;Safaee et al, 2014). According to Bauer et al (2020) the weight of adult flies can be a useful indicator of the conditions of the remains at the time of colonization as the adult weight is related to the pupal weight, which can be affected by chemicals, tissue type, and diet.…”