Departamento de Entomologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil.
Departamento de Biologia Animal, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Rio de Janeiro, Brazil.
J Med Entomol. 2021 Mar 12;58(2):558-566. doi: 10.1093/jme/tjaa239.
Chrysomya megacephala (Fab. 1794) (Diptera: Calliphoridae) is a very important species for forensic entomology, mainly contributing estimations of the postmortem interval (PMI) in judicial investigations. There are some doubts about the nocturnal oviposition of these flies, which could lead to errors in the PMI calculation. This study aimed to monitor the nocturnal oviposition behavior of this species through four experimental conditions carried out in laboratory. Ten cages, each containing five males and females (n = 100), were kept in a fume hood and subjected to total darkness or to artificial light for 11 consecutive hours. Two verifications were performed to determine whether the females deposited eggs on the substrate of ~20 g of chicken gizzards per cage. The first verification occurred at 9:00 pm in nocturnal experiments and at 09:00 am in diurnal experiments. The second verification occurred at 05:00 am in nocturnal experiments and at 05:00 pm in diurnal experiments. Each experiment lasted 5 d. Chrysomya megacephala deposited eggs at night under artificial light and in total darkness, but the amount of eggs was significantly lower when compared with the daytime experiments in dark conditions and under natural light. Oviposition occurred when the average temperature was around 25°C (± 2°C) and relative humidity around 73% (± 6%). Night oviposition is a possibility which should not be ruled out. Thus, future experiments are recommended.
红头丽蝇（Fab. 1794）（双翅目：丽蝇科）是法医昆虫学中非常重要的物种，主要用于推断法医学死亡时间（PMI）。关于这些蝇类是否在夜间产卵存在一些疑问，这可能会导致 PMI 计算错误。本研究旨在通过在实验室进行的四项实验条件来监测该物种的夜间产卵行为。十个笼子，每个笼子里有五对雌雄蝇（n = 100），放在通风橱里，持续处于完全黑暗或人工照明环境 11 小时。为了确定雌蝇是否会在每个笼子里约 20 克鸡胗的基质上产卵，进行了两次验证。第一次验证是在夜间实验的晚上 9 点和白天实验的上午 9 点进行的，第二次验证是在夜间实验的早上 5 点和白天实验的下午 5 点进行的。每个实验持续 5 天。在人工光照和完全黑暗的条件下，红头丽蝇会在夜间产卵，但与黑暗条件下和自然光下的白天实验相比，产卵量明显减少。当平均温度在 25°C（± 2°C）左右，相对湿度在 73%（± 6%）左右时，就会发生产卵。夜间产卵是一种可能，不应排除。因此，建议进行未来的实验。
