Diets of animal origin and their influence on the development of the immatures of Chrysomya albiceps (Diptera: Calliphoridae): implications for forensic entomology

In forensic entomology, the minimum and maximum post-mortem interval (PMI) is estimated on the basis of the developmental stages of necrophagous Diptera larvae on a corpse. The nutritional composition of the decomposing tissue, which can influence larval development rates, may impact the precision of this estimate. We compared the post-embryonic development of Chrysomya albiceps reared on bovine muscle and swine lung. Forty newly hatched fly larvae, per treatment, were placed on 60 g of the following tissues: bovine muscle (control) and swine lung (T1). Each treatment had three replicates. The experiments were maintained under controlled conditions (28 degrees C day/26 degrees C night, 70 +/- 10% RH and 12 h photophase). Flies reared on bovine muscle took significantly longer to complete their larval phase (8.1 days) than did larvae reared on swine lung (6.8 days). The total duration of development in bovine muscle was significantly slower (12.3 days) than in swine lung. Larvae that were reared on swine lungs were significantly heavier than larvae reared on bovine muscle. Total larval viability was high on pig lung (over 49%). The sex ratio was closer to the 1:1 ratio in bovine muscle (rs = 0.55), with a slightly greater proportion of female larvae. The percentage of abnormality remained within the predicted range. The results show that the different tissues influenced larval development. This underlines the importance of considering the type of cadaveric tissue when larval development is used to calculate the minimum PMI in forensic investigations.