Precocious egg development in the blowfly Calliphora vicina: implications for developmental studies and post-mortem interval estimation.
The occurrence of precocious egg development in forensically important calliphorid species has previously been reported; however, the frequency of occurrence in both wild and captive colonies, and the consequent effects on developmental studies and post-mortem interval (PMI) estimates, are largely unknown. A PMI estimate based on samples developed from precocious eggs could be extended by the entire period of embryogenesis, which at 22 °C would result in a significant error of around 24 h. This study examined the occurrence of precocious egg development in Calliphora vicina Robineau-Desvoidy (Diptera: Calliphoridae) wild-caught and captive-bred adults by investigating the presence of larvae in the adult female genital chamber and by monitoring hatching times of entire batches of eggs throughout embryogenesis, respectively. A total of 8.82% of gravid wild-caught females contained a larva in the genital tract (i.e. a precocious egg). This indicates that all specimens collected should be considered potentially precocious for the purpose of PMI estimation. Less than 2.55% of a batch of eggs laid by captive females were precocious; protocols for minimizing the effect of precocious eggs on developmental studies are suggested.
School of Biological Sciences, University of Portsmouth, Portsmouth, UK.
K
K
Davies
M
M
Harvey
D000818:Animals; D004175:Diptera / Q000254:growth & development / Q000502:physiology*; D004739:England; D005260:Female; D044707:Forensic Sciences; D007814:Larva / Q000254:growth & development / Q000502:physiology; D010058:Oviposition; D052285:Ovoviviparity; D010063:Ovum / Q000254:growth & development / Q000502:physiology; D013997:Time Factors