| Summary: | 碩士 === 國立臺灣大學 === 昆蟲學研究所 === 101 === Maggot mass, the aggregation of fly larvae, causes obvious changes on the developmental rate of maggots by producing abundant saliva and maggot mass heat. Many previous researches have also mentioned that the temperature in maggot mass is extremely higher than that of ambient surroundings. In these regards, when using the development of fly larvae on corpse to estimate the post-mortem interval (PMI), maggot mass heat is an important parameter which has to be considered. In our experiment, the larval aggregation of a dominant necrophagous blow fly species, Chrysomya megacephala (Fabricius), in Taiwan was examined, and the temperatures of maggot mass were also recorded. The number of larvae in maggot mass used in this study are 1000, 2000, 4000, 6000, 8000 and 12000. Temperatures recorded in this study in maggot mass were higher than that in the previous studies, which used fewer larvae to record the maggot mass heat. Within appropriate range, the temperatures increased with the numbers of larvae in mass. However, the temperature differences between maggot mass and surroundings decreased with the increasing of ambient temperature. When ambient temperature reaching to 40°C, the approximately favorite temperature of C. megacephala larvae in previous study, the temperature of maggot mass was almost equal to that of the surroundings; and there is no temperature raise in maggot mass even the number of larvae increased. The maggot in mass could move in and out the mass to form a looser mass to avoid overheating, or regulate their temperature. According to the results, there is a minimum maggot developmental duration, approximately 64 hours during larvae hatched to postfeeding. Thus, when ambient temperature reached to 40°C, or the minimum developmental duration arrived, the effects on temperature and developmental rate attributed to the size of maggot mass could probably be neglected when using in PMI estimation.
|
|---|
