Consequences of Lead Exposure on Lucilia sericata Development
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Grant: Students Partnering with Faculty (SpF)
Ava La Lande
CoPIs:
Chamodhi Ranathunga, Jonelle Brown, Andrea Oncoy
College:
The Dorothy and George Hennings College of Science, Mathematics, and Technology
Major:
Biology
Faculty Research Advisor(s):
Denise Gemmellaro
Abstract:
The study of forensic entomology, specifically medico-legal entomology, is the field of forensic sciences that uses insects and arthropods found on a corpse to help investigators answer various questions. In forensic investigations, time of colonization (TOC), also known as the minimum post-mortem interval (mPMI), utilizes entomological evidence to estimate how long the remains have been exposed. The rate of insect development strictly depends on abiotic variables such as environmental conditions (temperature), nutritional content of the food, resource availability, and xenobiotics. Considering that insects (primarily flies) are known to arrive on a carcass shortly after death, estimating how old the insects are may result in estimating how long a body has been there. The estimate, however, may be skewed when the insects are exposed to foreign substances, not commonly found in human bodies. When fly larvae consume chemical substances, their predictable development may be hindered. These foreign substances, in addition to controlled and illegal substances, also include prescription and over-the-counter medications. The LOFT (Laboratory of Forensic Things) has been focused on the effects of chemicals on blowfly larvae development and this study wanted to assess the effects of lead on the development of Lucilia sericata (Meigen) (Diptera: Calliphoridae). Lead is a common heavy metal that, along with antimony and barium, is one of the main components of gunshot residue, and it remains embedded in soft tissues surrounding entry and exit wounds. We placed 1st instar larvae in rearing containers and fed them with lead-treated beef liver. We used three different lead concentrations (0.025 mg/L, 0.05 mg/L, and 0.1 mg/L) and a control consisting of liver without lead. The incubator was set to a 12:12 hour photoperiod, temperature of 25 °C at 60% humidity. We performed two checks per day during which we sampled 10 random maggots from each container, assessed the development of the maggots, and weighed them. Once pupation was achieved, each pupa was weighed, measured, photographed, and placed in individual containers until eclosion. While we are still analyzing our data and we only have preliminary results, we noticed there were low mortality rates across all treatments and larger weights in the control. Pupation time was between six to eight days for each treatment. Future studies will be performed using different species of blow flies and different xenobiotics to assess significant differences in their development that can, in turn, affect the estimation of the TOC and mPMI.