Effects of Hexavalent Chromium Exposure on Growth and Development of the Blowfly, Chrysomya Chloropyga (Diptera:...

Hexavalent chromium (Cr⁶⁺) is a known carcinogen that has been listed as a priority pollutant by the Environmental Protection Agency (EPA). The toxic effects of Cr⁶⁺ in some organisms, especially aquatic animals have received considerable attention over the years but not much is known about the adverse effects of Cr⁶⁺ in terrestrial insects despite their potential exposure to Cr⁶⁺ through ingestion of contaminated food and water. Therefore, this study aimed at investigating the effects of Cr⁶⁺ on the survival, growth and development of the blowfly, Chrysomya chloropyga. The eggs of C. chloropyga that were collected from laboratory stock were exposed to dietary Cr⁶⁺ at different concentrations; 0, 4, 8, 12, 16, and 20 mg/mL and the eggs were monitored throughout the developmental stages till adult emergence, during which growth (length, width, and weight at larval and pupal stages) and developmental parameters (duration of development at different stages, egg hatchability, pupation, and adult emergence) were measured. Exposure to Cr⁶⁺ prolonged the developmental period in the blowflies with total developmental period reaching 231.00 ± 1.45 h in the insects that were treated with 20 mg/mL Cr⁶⁺ compared with 217.91 ± 1.16 h in the control. The percentage hatchability, pupation rate and number of emerged adults reduced significantly in groups exposed to Cr⁶⁺ (especially at 20 mg/mL) compared to the control. The mean length, width and weight decreased significantly in insects exposed to dietary Cr⁶⁺ at all the immature stages. The results of this study showed that dietary Cr⁶⁺ exposure have adverse effects on the growth and development of C. chloropyga.