Ocorrência e influência de insetos em lesões pós-morte infligidas em suínos em um fragmento florestal urbano, Manaus, Brasil

Abstract

The activity of insects on cadavers can complicate the interpretation of facts in a criminal investigation. Through feeding, they can produce injuries similar to inflicted wounds or modify pre-existing wounds. The general objective of the present study was to evaluate the occurrence and influence that insects can have on postmortem lesions in pig carcasses. Four experiments were conducted using pigs weighing approximately 15 kg in an urban forest fragment in Manaus. Puncture wounds were inflicted on two pigs and incised wounds on the other two. Two lesions on each animal were isolated for control. Values of length/diameter, width, and area over time were measured, and based on these data, analyses of changes in the size and shape of the lesions were performed. Additionally, insect feeding and oviposition activities were observed. The size analysis showed significant results between the lesions with and without access to arthropods for width, but not for length/diameter and area. In the shape analysis, a significant relationship was found between treatments and the height-to-width ratio for incised wounds in the presence of insects. Oviposition was observed inside two of the eight exposed lesions. Formicidae and Vespidae were present in the lesions until the bloated stage and were recorded feeding on the wounds. Adult Calliphoridae were present in the lesions in all observed stages, but with fewer specimens in the fresh stage. Diptera larvae began activity within the first three days of the experiment in four of the eight lesions with insect access. The presence of insects in postmortem lesions influenced the size and shape of the lesions; however, there also seems to be an effect on decomposition. Information on insect activities in these lesions can assist professionals in conducting investigations.