Forensic Science Program, School of Diagnostics and Applied Health Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia (National University of Malaysia), Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur, Malaysia.
Parasitol Res. 2012 Nov;111(5):2179-87. doi: 10.1007/s00436-012-3070-z. Epub 2012 Aug 12.
In forensic entomology, breeding of fly larvae in a controlled laboratory environment using animal tissue is a common technique to obtain insect developmental time for the estimation of postmortem interval. Previous studies on growth media are mostly on the effect of different diets on fly development. However, the interaction effects between temperature and food type used have not been explored. The objective of this study was to compare the use of cow's liver agar and raw liver on the development of a forensically important fly, Megaselia scalaris (Loew). This study also determined the interaction between different temperatures and different food types on the growth of this species. A total of 100 M. scalaris eggs were transferred into each of the two media mentioned above. Liver agar was prepared by adding dried ground liver into nutrient agar, whilst raw liver was naturally prepared from the same animal source. This experiment was conducted at 27, 30 and 33 °C in an incubator in a continuously dark condition. Length and weight of larvae, puparia and adult samples were determined. Total developmental times for larvae feeding on liver agar at each temperature were approximately 7-15 h slower than those feeding on raw liver. Survival rates were almost equal in both diets but were lower at 33 °C. Mean larva length in both diets did not differ significantly at all temperatures, but larvae feeding on liver agar had lower mean weight values than those in raw liver at 30 and 33 °C. The effect of temperature was significant in female puparia weight and male adult weight whereas the effect of diet types was significant in both male and female puparia size and weight. Interaction effects of temperature and food type on M. scalaris puparium size and adult weight were significant, indicating that puparium size and adult weight depended on both food type and temperature. This experiment highlighted the use of cow's liver agar as an alternative diet to breed M. scalaris in the laboratory and the importance of considering the interaction effect between temperatures and food types when deciding the most suitable medium in fly larva rearing.
在法医昆虫学中，在受控的实验室环境中使用动物组织来繁殖蝇幼虫是一种常用技术，可用于获取昆虫发育时间以估计死后时间。以前关于生长培养基的研究主要集中在不同饮食对蝇类发育的影响上。然而，尚未探索使用的温度和食物类型之间的相互作用效应。本研究的目的是比较使用牛肝琼脂和生肝对法医重要蝇种 Megaselia scalaris (Loew) 的发育的影响。本研究还确定了不同温度和不同食物类型对该物种生长的相互作用。将总共 100 个 M. scalaris 卵转移到上述两种培养基中的每一种中。肝琼脂是通过将干燥的磨碎肝脏添加到营养琼脂中制备的，而生肝则是从相同的动物来源自然制备的。该实验在 27、30 和 33°C 的黑暗条件下在培养箱中进行。测量幼虫、蛹和成虫样本的长度和重量。在每个温度下，幼虫在肝琼脂上的总发育时间比在生肝上的发育时间慢约 7-15 小时。两种饮食的存活率几乎相等，但在 33°C 时较低。在所有温度下，两种饮食的幼虫平均长度没有显著差异，但在 30 和 33°C 时，在肝琼脂上饲养的幼虫的平均重量值低于在生肝上饲养的幼虫。温度对雌性蛹重和雄性成虫重的影响显著，而饮食类型对雄性和雌性蛹大小和重量的影响显著。温度和食物类型对 M. scalaris 蛹大小和成虫体重的相互作用效应显著，表明蛹大小和成虫体重取决于食物类型和温度。该实验强调了在实验室中使用牛肝琼脂作为饲养 M. scalaris 的替代饮食，并强调了在决定最适合的蝇幼虫饲养培养基时考虑温度和食物类型之间相互作用效应的重要性。
