The feeding behaviour and general histological characteristics of the gastrointestinal tract of South African cave-dwelling amphipods

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dc.contributor.author Van Tonder, Simone
dc.date.accessioned 2008-06-23T10:55:44Z
dc.date.available 2008-06-23T10:55:44Z
dc.date.issued 2008-06-23T10:55:44Z
dc.identifier.uri http://hdl.handle.net/10210/678
dc.description.abstract Amphipods are the most ubiquitous animals, after nematodes, on earth. Although there are several terrestrial amphipod species, most are aquatic. They are familiar animals in the water table exposed in cave environments and boreholes. The food source on which the amphipods depend was not directly observable in the cave environments frequented by the amphipods. In order to establish the role cave-dwelling amphipods play in ecology, the primary purpose of this study was thus to determine what cave-dwelling amphipods feed on. Amphipod, water and sediment samples were collected from five different caves, in the northern part of South Africa, namely Koelenhof Cave, Sterkfontein Cave, Ficus Cave, Peppercorn’s Cave, and Irene Cave. Following collection and transportation, resulting in zero amphipod mortalities, all of the samples were transferred to rectangular fish tanks stored in an environmental room, set up in such a way as to mimic the conditions in the caves as closely as possible. Long term adaptability and survival proved to be a successful undertaking, resulting in the death of only two amphipods per tank. Scanning electron microscopy was used to observe the mouthparts of the amphipods in order to begin establishing their feeding behaviour. Standard microtechniques were carried out to establish the general histological orientation and histology of the gastrointestinal tract. A Histochemical Fluorescent staining method was employed, and a reddish-orange fluorescence was observed, thereby indicating the presence of mucous in the GIT. Several feeding experiments were carried out, and it was established that on average amphipods can survive without a food source for a maximum of sixty ABSTRACT xv days. Through a series of different feeding experiments, it was determined that amphipods ingest bat faeces, leaf litter, sediment and yeast, with leaf litter producing the highest rate of survival. It was also observed that amphipods, regardless of body size, are predators, scavengers, and cannibals, which may provide an explanation as to why amphipods display evasive behaviour. Microbiology plays a vital role in determining what amphipods feed on, and therefore water, soil, and digestive contents of amphipods were studied using a wide array of microbiological analyses: Heterotrophic Plate Counts; Total Coliforms; Faecal Coliforms; Faecal Streptococci; Confirmatory test for Escherichia coli; Detection of Clostridium, Pseudomonas, and Salmonella. According to the South African Bureau of Standards, the quality of the water contained within all four of the caves in this study may not be used for human consumption prior to undergoing various purification processes. Once the role that cave-dwelling amphipods play in ecology has been firmly established it may then be possible to make use of amphipods as biological indicators, because since they inhabit cave streams and groundwater and are sensitive to pollutants, declines in their populations could indicate a decline in the water quality in their streams and surrounding groundwater supply. en
dc.description.sponsorship Dr. J.F. Durand en
dc.language.iso en en
dc.subject Amphipoda feeding and feeds en
dc.subject Gastrointestinal system en
dc.title The feeding behaviour and general histological characteristics of the gastrointestinal tract of South African cave-dwelling amphipods en
dc.type Thesis en

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