López-García Jaime, Martín-Vega Daniel
Departamento de Ciencias de la Vida, Universidad de Alcalá, Alcalá de Henares, Spain.
Instituto Universitario de Investigación en Ciencias Policiales, Alcalá de Henares, Spain.
Med Vet Entomol. 2025 Mar;39(1):33-40. doi: 10.1111/mve.12749. Epub 2024 Aug 19.
Most blow flies (Diptera: Calliphoridae) species are sarcosaprophagous during the larval stage, primarily feeding on the soft tissues of carcasses during the early stages of decomposition, making them valuable forensic indicators for minimum post-mortem interval (minPMI) estimations. Like other insects, their developmental rates are strongly influenced by the environmental temperature. Although several studies have examined the influence of temperature on the development of different blow fly species, the impact of cold temperatures remains largely unstudied, despite its potential forensic implications. The present study investigates the effect of three cold temperatures (0, -2.5 and -5°C) on the survival of Calliphora vicina embryos of five different ages (0%, 20%, 40%, 60% and 80% of the total embryonic development) and two exposure times (6 and 24 h). Our results revealed significant differences in egg survival at the earliest embryonic stages (0% and 20% of the total embryonic development), resulting in high mortality rates. While at 20% of the total embryonic development high mortality was only observed under -5°C, at 0% of the total embryonic development high mortality rates were observed at all the temperatures tested. Although C. vicina embryos demonstrate tolerance to cold temperatures once they have completed the first 20% of the total embryonic development, potentially mitigating the impact of cold weather events, the possibility of minPMI underestimations due to the death of the first egg batches should not be disregarded. Additionally, considering that the embryonic development stages may last for several days under low temperatures, caution should be taken in the analysis of entomological evidence if a cadaver is discovered following cold weather episodes.
大多数丽蝇（双翅目：丽蝇科）物种在幼虫阶段是肉食性腐食动物，主要在尸体分解的早期阶段以尸体的软组织为食，这使它们成为估计最短死后间隔时间（minPMI）的重要法医指标。与其他昆虫一样，它们的发育速度受到环境温度的强烈影响。尽管有几项研究探讨了温度对不同丽蝇物种发育的影响，但低温的影响在很大程度上仍未得到研究，尽管其具有潜在的法医意义。本研究调查了三种低温（0、-2.5和-5°C）对五种不同发育阶段（占胚胎发育总数的0%、20%、40%、60%和80%）的红头丽蝇胚胎存活率的影响，以及两种暴露时间（6小时和24小时）。我们的结果显示，在胚胎发育的最早阶段（占胚胎发育总数的0%和20%），卵的存活率存在显著差异，导致死亡率很高。虽然在胚胎发育总数的20%时，仅在-5°C下观察到高死亡率，但在胚胎发育总数的0%时，在所有测试温度下均观察到高死亡率。尽管红头丽蝇胚胎在完成胚胎发育总数的前20%后表现出对低温的耐受性，这可能减轻寒冷天气事件的影响，但不应忽视由于第一批卵死亡而导致minPMI低估的可能性。此外，考虑到在低温下胚胎发育阶段可能持续数天，如果在寒冷天气事件后发现尸体，在分析昆虫学证据时应谨慎。
