Avermectins and milbemycins are commonly used in agro-ecosystems for the control of parasites in domestic livestock. As integral members of agro-ecosystems with importance in maintaining pasture health through dung burial behaviour, dung beetles are an excellent, non-target, bio-indicator taxon for examining potential detrimental effects of pesticide application. The current study uses the dung beetle species, Euoniticellus intermedius (Reiche), as a bio-indicator to test the relative toxicity of four different anthelmintics in dung residues. There have been numerous laboratory and field trials on these four anthelmintics but there has never been a laboratory trial comparing ivermectin, eprinomectin, doramectin and moxidectin under precisely the same conditions. The effects of avermectin and milbemycin toxicity are not confined to parasitic nematodes and arthropods, but also extend to a large variety of beneficial invertebrate species, which use the dung as a microhabitat and breeding resource. Over time, pesticide usage indirectly affects the rate of dung degradation through adverse effects on dung beetles. This potential problem constitutes the main focus of this study. The present and previous studies have indicated no significant effect on the survival of adults but a significant reduction in reproductive rate and reproductive success. Over time, reduced reproductive rate would result in decreased population sizes in the dung beetle community and, ultimately, a decrease in the rate of dung degradation and dung burial. It is, thus, vitally important to create awareness about the importance of dung beetles and sound farming practices for healthy agro-ecosystems. / Dissertation (MSc)--University of Pretoria, 2014. / lk2014 / Zoology and Entomology / MSc / Unrestricted

Recent years have seen a dramatic increase in first generation bio-fuel production, mainly driven by concerns of climate change and rising prices of transportation fossil fuels. Due to significant pressure on the few available food sources, second generation bio-fuels have entered the fray, as a sustainable alternative. This research‟s aim was to search for cellulolytic micro-organisms and enzymes from the gut of the dung beetle, Euoniticellus intermedius, (Coleoptera: Scarabaeida) that can be used in the production of second generation bio-fuels. Dung beetle larvae were dissected and the gut micro-flora cultured in cellulose medium. Bacterial growth and cellulase activity was monitored on a daily basis. DNA isolation was then done on the cellulose medium-cultured microbes and the isolated DNA cloned in E. coli. The clones were screened for cellulase activity using plate assays. A total of 7 colonies out of 160 screened colonies showed positive CMC (endo-β-1,4-glucanase) and MUC (cellobiohydrolase) activities. Sequencing of these positive colonies yielded mostly bacteria belonging to the Enterobacteriaceae family, most of which have not been previously reported to have cellulase activity. This study‟s findings prove that in addition to this dung beetle‟s gut being a fruitful source of microbial biodiversity, it is also a potential source of cellulolytic micro-organisms and enzyme activities that will aid the function and design of future bioreactors for the bio-fuel industry.