Chronology of the Intrapuparial Development of the Blowfly Chrysomya albiceps (Diptera: Calliphoridae): Application in Forensic Entomology.

Insects display different patterns of development, and blow flies have one of the most specialized patterns of intrapuparial development of all. In forensic entomology, pupae can be used as a tool to estimate the minimum postmortem time interval (minPMI). We analyzed the intrapuparial development of Chrysomya albiceps (Diptera: Caloricidade), whose larvae had been fed pig lungs and reared in a climate-controlled room at 28°C day/26°C night, 70 ± 10% RH, and 12 h of photophase and monitored daily. After the third-instar larvae abandoned their diet, the process of pupariation and pupation was monitored. At pre-established times, five pupae were collected, euthanized, and fixed in 5% formaldehyde, inside polypropylene test tubes with caps. Since they were the first, they were classified as 0 h pupae. Twelve collections occurred until the emergence of the adults, at 0, 2, 4, 6, 8, 10, 24, 30, 48, 54, 72, 78, 96, and 99 h (n = 84). The fixed pupae were dissected under the microscope, with the aid of anatomical tweezers and hypodermic needles, and photographed. The stages of metamorphosis and the morphological alterations occurring during the process were identified, described, and recorded before and after pupation. These phases were: pupation, larval pupal apolysis, cryptocephalic, phanerocephalic, pharate adult, emergence, and adult. The cryptophalic phase occurred between 4 and 6 h after pupation; the phanerocephalic phase between 6 and 10 h after; the pharate adult phase between 24 and 96 h after; and the imago/emergence phase 99 h after pupation.