Arthropod succession on exposed and shaded mammalian carcasses in Nsukka, Nigeria

Abstract

Ten Wistar rats were used as model to study arthropod succession on carcass under shade and exposed conditions. Carcass decomposition took longer periods under shade than on the exposed site. Four decomposition stages (fresh, bloated, decay and dry) were observed. A total of 164 arthropods were collected belonging to three classes: Insecta, Arachnida and Crustacean. Insects formed 95.12 %, arachnids 1.22 % and crustaceans
3.66 %. Large numbers of arthropods were found on the exposed carcass than the shaded carcass. Calliphorids and Sarcophagids were the primary colonizers observed breeding on the carcasses. The most abundant insects include Chrysomya albiceps (13.4 %) and Lucilia serricata (10.37 %). Other dipterans including Muscidae, Phoridae, Sepidae, Fannidae and Anthomyiidae were found during the bloated and decay stages. Families of the coleopterans including; Dermestidae, Silpgidae, Staphylinidae and Histeridae were observed during the bloated to the dry stages and fed on the immature dipterous maggots and carrion remains. Hymenopterans were observed throughout the process of decomposition and played a vital role in carcass decomposition. Other arthropods arrived mostly during the decay stage. Species richness on the carcasses peaked during the decay stage. The rate of decomposition of carcasses is affected by environmental factors such as temperature, relative humidity, precipitation and insect
abundance.

Keywords: Post mortem interval, Carcass decomposition, Insect abundance, Forensic entomology