Body Size and Cuticular Hydrocarbons as Larval Age Indicators in the Forensic Blow Fly, Chrysomya albiceps (Diptera: Calliphoridae)
Ahmed, Fayeza Alotaibi, Mohammed Alkuriji, Salwa AlReshaidan, Reem Alajmi, Dina M. Metwally, Bassam Almutairi, Majed Alorf, Rania Haddadi, and Ashraf . 2020
Chrysomya albiceps (Wiedemann 1819) is one of the most important insects in forensic entomology. Its larval
developmental and survival rates are influenced by nutritional resources, temperature, humidity, and geographical
regions. The present study investigated the possibility of relying on body size and cuticular hydrocarbon
composition as indicators for age estimation of the different larval instars of C. albiceps. Larvae were
maintained in standardized laboratory conditions at different experimental temperatures. All larval instars
(first, second, and third) were randomly collected for measuring their body sizes and for estimating their cuticular
hydrocarbons at different rearing temperatures (30, 35, 40, and 45°C) using gas chromatography–mass
spectrometry (GC–MS). Results indicated that the duration of larval stage was temperature dependent as it
gradually decreased on increasing the rearing temperature (30, 35, and 40°C) except 45°C at which larval development
was ceased. In contrary, larval body size, in terms of length, width, and weight, was temperature
dependent as it gradually increased with larval development on increasing rearing temperature except at 45°C
at which larval development was ceased. The GC–MS showed a significant difference in the extracted components
of cuticular hydrocarbons between different larval instars reared in the same temperature and between
the same larval instar that reared at different temperatures. Furthermore, the highest and lowest amounts of
cuticular hydrocarbons were detected at 35 and 40°C, respectively. Overall, larval body size and cuticular hydrocarbon
components were temperature dependent within the range 30–40°C, which may suggest them as
possible reliable age indicators for estimating the postmortem interval in the field of medicolegal entomology.
Aedes aegypti (Culicidae), the mosquito that causes yellow fever, is regarded as a significant vector for
many disease agents. The current study sought to learn more about mosquito mid-gut…