Slone D H, Gruner S V
USGS Florida Integrated Science Center, 2201 NW 40th Terrace, Gainesville, FL 32605, USA.
J Med Entomol. 2007 May;44(3):516-23. doi: 10.1603/0022-2585(2007)44[516:tilaoc]2.0.co;2.
The growth and development of carrion-feeding calliphorid (Diptera: Calliphoridae) larvae, or maggots, is of great interest to forensic sciences, especially for estimation of a postmortem interval (PMI). The development rate of calliphorid larvae is influenced by the temperature of their immediate environment. Heat generation in larval feeding aggregations (=maggot masses) is a well-known phenomenon, but it has not been quantitatively described. Calculated development rates that do not include internally generated temperatures will result in overestimation of PMI. Over a period of 2.5 yr, 80 pig, Sus scrofa L., carcasses were placed out at study sites in north central Florida and northwestern Indiana. Once larval aggregations started to form, multiple internal and external temperatures, and weather observations were taken daily or every few days between 1400 and 1800 hours until pupation of the larvae. Volume of each aggregation was determined by measuring surface area and average depth. Live and preserved samples of larvae were taken for species identification. The four most common species collected were Lucilia coeruleiviridis (=Phaenicia) (Macquart) (77%), Cochliomyia macellaria (F.) (8.3%), Chrysomya rufifaces (Macquart) (7.7%), and Phormnia regina (Meigen) (5.5%). Statistical analyses showed that 1) volume of a larval mass had a strong influence on its temperature, 2) internal temperatures of masses on the ground were influenced by soil temperature and mass volume, 3) internal temperatures of masses smaller than 20 cm3 were influenced by ambient air temperature and mass volume, and 4) masses larger than 20 cm3 on the carcass had strongly regulated internal temperatures determined only by the volume of the mass, with larger volumes associated with higher temperatures. Nonsignificant factors included presence of rain or clouds, shape of the aggregation, weight of the carcass, species composition of the aggregation, time since death, or season.
食腐丽蝇（双翅目：丽蝇科）幼虫（即蛆虫）的生长发育对法医学极为重要，尤其是在死后间隔时间（PMI）的估计方面。丽蝇幼虫的发育速度受其周围环境温度的影响。幼虫取食聚集物（即蛆团）中产生热量是一个众所周知的现象，但尚未进行定量描述。未考虑内部产生温度而计算出的发育速度会导致对PMI的高估。在2.5年的时间里，80头家猪（Sus scrofa L.）尸体被放置在佛罗里达州中北部和印第安纳州西北部的研究地点。一旦幼虫聚集开始形成，在1400至1800时之间，每天或每隔几天对多个内部和外部温度以及天气情况进行观测，直至幼虫化蛹。通过测量表面积和平均深度来确定每个聚集物的体积。采集活的和保存的幼虫样本进行物种鉴定。采集到的四种最常见的物种分别是绿蝇（Lucilia coeruleiviridis (=Phaenicia) (Macquart)）（77%）、肉蝇（Cochliomyia macellaria (F.)）（8.3%）、红头丽蝇（Chrysomya rufifaces (Macquart)）（7.7%）和黑尾黑麻蝇（Phormnia regina (Meigen)）（5.5%）。统计分析表明：1）蛆团的体积对其温度有强烈影响；2）地面上蛆团的内部温度受土壤温度和蛆团体积影响；3）体积小于20立方厘米的蛆团的内部温度受环境气温和蛆团体积影响；4）尸体上体积大于20立方厘米的蛆团具有仅由蛆团体积决定的强烈调节的内部温度，体积越大温度越高。不显著的因素包括是否下雨或多云、聚集物的形状、尸体重量、聚集物的物种组成、死亡时间或季节。
