Intrapuparial development of Peckia pexata (Wulp, 1895) (Diptera: Sarcophagidae)

Abstract

Sarcophagidae flies have great forensic importance, since different instars of their larval development are used in the determination of the postmortem interval (PMI) of corpses. However, for many species, intrapuparial developmental data are scarce. Here we analyzed the intrapuparial development of the sarcophagid Peckia pexata and describe the chronological and morphological changes that occur during metamorphosis. We reared approximately 330 specimens originating from the Colombian Amazon in the laboratory. Prepupae were identified by size reduction and coloration change. During the first five days of the study, four individuals were sampled every three hours, then every six hours until adult emergence. Specimens were fixed in 96% alcohol, then immersed in Carnoy solution for 24 hours and in formic acid (5%) for 48 hours for dissection and analysis of morphological changes. Four morphological phases of intrapuparial development of P. pexata were observed: 1) larva pupa apolysis, which lasted, in average, 9 h; 2) cryptocephalic pupa, 6 h; 3) phanerocephalic pupa, 6.5 h; and 4) pharate adult (transparent eyes, 48 h; yellow eyes, 216 h; pink eyes, 35 h; and red eyes, 52 h). The pharate adult was fully formed at 340 h and adult emergence occurred at 372.5 h or 15.5 days. We also described the formation of the prepupa, the pupariation and the final metamorphosis for the imago and compared it with the known events for Peckia intermutans, Peckia lambens (Sarcophagidae) and Lucilia eximia (Calliphoridae).