The Time between Death and the Discovery of the Corpse - Assignment Example

Entomological evidence Post mortem interval (PMI) is the time between death and the discovery of the corpse and can be estimated by entomological evidence. Estimation of PMI can be done by examining the developmental stage of particular insect species such as blowfly larvae collected from a corpse. PMI determinations are affected by factors that have an effect on the larval size and the growth rate. This study was conducted to explore the competitive effects of larval overcrowding on Calliphora vomitoria reared on the liver, brain and muscle tissue of a pig.

The main hypothesis for the research was the effect of larval overcrowding on the size, rate of development and survival of C. vomitoria. This highlighted the aim of the study to show the importance of considering the effects of larval crowding that could cause PMI errors during casework. It was found out that increased larval crowding resulted in faster development of C. vomitoria and the size of C. vomitoria that could cause oversestimation and undersestimation of PMI respectively if not accounted for during casework.

The major limitation in this research is that the study only explored development during larval stages. This means that further investigations are needed before making direct comparisons with the results. Moreover, comparison with other studies was difficult because the muscle used in each experiment had a different origin and was likely to cause variation in the results. The consideration of space available to larvae within a culture affects competitive interactions would be required.The research had several strengths while conducting the research.

The researchers ensured that food was always in excess so that competitive effects could be ruled out. They also reared the cultures in different pig tissue enabling them to determine the development rate at different larval densities in cultures reared in the brain, liver and muscle while keeping the experimental conditions identical. The effects of larval crowding at three intervals on each of the three tissues were observed for the greatest changes in body tissues. It was found out that the brain was the least nourishing and due to lower protein levels and higher water content, there was rapid consumption compared to the other tissues.

In conclusion, the research was justified because it effectively gave light to how overcrowding during larval stages of development resulted in a competitive feeding environment therefore affecting size, development rate and survival. This affected estimation of PMI and is critical in the forensic investigations. The results indicated that higher temperatures attained and more efficient feeding increased by larval crowding caused faster development of C. vomitoria. This was likely to cause overestimation of the PMI if not considered.

It was also observed that the degrees of crowding differed on each tissue type, suggesting the importance of knowledge of the likely positions of larvae feeding on a corpse. The tendency to produce undersized individuals could lead to underestimation of PMI. It is important to consider factors such as larval overcrowding in estimation of PMI during casework (Ireland & Turner, 2005). BibliographyIreland, S., & Turner, B. (2005). The effects of larval crowding and food type on the size and development of the blowfly, Calliphora vomitoria.

Forensic Science Interantional , 159, 175-181.