Age estimation of forensically important blowfly pupae. Morphological and histological methods

Approximately 50% of the immature development of blowflies takes place in the pupal stage which makes age estimation difficult. This article presents morphological and histological milestones for the pupal development of Calliphora vicina and Lucilia sericata . Rearing was carried out at 25A degrees C. Pupae were sampled every 24 h and either weighed or killed. Puparia were removed and pictures were taken. Additionally for analyzing nuclei volumes, adipocytes and histology, pupae were fixed in formalin, sliced and stained with hematoxylin and eosin (7 A mu m, H&E). Character sheets for external pupal morphology were developed, defining and describing 10 morphological milestones for pupal development. Significant loss of weight was observed during metamorphosis for both species. Larval nuclei showed a reduction of up to 25.3 % of the volume during the first days of histolysis and the number of adipocytes was reduced by up to 52.4 %. The character sheets show that a combination of morphological characters can be used to estimate age (+/- 12 h) for the pupae of the blowflies C. vicina and L. sericata. Histological changes can confirm or even improve these results.