Studies on two species of blow flies (Diptera: Calliphoridae) with particular reference to their forensic importance

Abstract

The present work deals with the experimental studies on different aspects of biology of two species of blow flies i.e. Chrysomya megacephala (Fabricius) and Chrysomya rufifacies (Macquart) which can be potentially important from forensic point of view. Both of them are forensically important species distributed in many parts of the world and are available throughout the year in tropical regions of India. Larvae of both species have been reported in association with human corpses in several cases. The research work can be summarized under the following headings as follows: Effect of starvation on larval behavior: The postfeeding larval stage in blow flies is generally an irreversible condition when the fully grown third instar larvae stop feeding and give no response towards food. The larvae of most species then disperse away from their feeding medium and pupariate. There are several case reports about the use of postfeeding larvae as forensic evidence. It is a matter of common observation that the postfeeding stage can be reached earlier than the expected time if food becomes unavailable. However, no information is available whether postfeeding stage induced by scarcity of food is also irreversible. Similarly, we do not know what is the minimum period of development required by the larvae of different blow fly species to enable their survival as postfeeding larvae and consequent pupariation in the absence of food. During the present studies, it has been observed that the larvae must feed for at least 35h in order to be capable of reaching the postfeeding stage. This is the period required by the larvae to reach the third instar stage.