Biology of Lechwe flies MUSCA TEMPESTATUM bezzi with emphasis on the Nutritional requirements as provided by the Lechwe Antelope in Zambia

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Muntemba, D. C
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Studies on the feeding behaviour of Musca tempestatum were carried out in order to investigate the biology of the fly and its relationship to the lechwe antelope. This was done by observing the fly's feeding activities on the antelope and its breeding activities on the lechwe faeces on which it oviposits. The larvae hatch out on the faeces and then migrate into the faeces. This is because, due to crust formation on the surface of the faeces, solidification of faeces and loss of water levels, there is left a small moist space in the middle of the faeces, into which the larvae congregate after making tunnels through which their posterior spiracles are exposed for air. The whole larval stage is accomplished within faeces and therefore larvae depend on faeces for food. The composition of the faeces and their variation was studied in the laboratory so as to investigate the effect of these variations on the survival of M« tempestatum dependent upon lechwe faeces. The detailed readings of moisture and nitrogen percent (dry weight percent of nitrogen) per month are tabulated in the appendices. The results showed that there were variations in the composition of faeces according to the months. This could have been due to seasonal changes in the composition of pasture grasses on which the antelopes feed which could have influenced the composition of faeces directly. Qorrod, (1959); Sen and Butterworth and Arias, (1965) c.f. Greenham, (1972) pointed out that differences in protein and fibre iv content between grass species were much less important than the differences between immature and mature grass of the same species. Sizes and weights of emerged flies reared at different nitrogen percentages were taken to soe whether these were affected by the composition of faeces. Results are shown in the dissertation. Experiments were carried out on the effect of food substances such as sugar, fresh liver and fresh faeces with the combinations of water on the survival of M. tempestatum adults. The flies used for the experiments were collected from the field within faeces in the immature forms, (eggs, larvae, pupae) and then reared in the laboratory. The immature stages of the fly are being described for the first time, other works have shown the behaviour of the adult flies, Patton, (1936). The number of the surviving flies fluctuated between the treatments, with the highest being demonstrated by flies fed on sugar and water and the lowest was found among flies fed on fresh faeces and water. Statistical analyses were done on the numbers of flies remaining alive at the end of the experiments to note whether there were any significant differences between treatments. The results of these experiments indicated that some of the foods given to the flies did not promote or increase survival; which meant that the food qualities obtained from these food substances were used for purposes other than survival (purposes such as reproduction). To this effect further experiments were done in the laboratory to investigate the effect of food quality on reproduction. Crude determinations of nitrogen content in the faeces which were done showed that there were variations which ranged from 2.5% to 6,25$, The highest nitrogen content was taken as a high quality and the lowest as a low quality type of food. The experiments started with varying nitrogen content. The effect of quality was interpreted by the number of eggs laid per larva present initially. It has been shown that M. tempestatum oviposits on fresh lechwe faeces and that the faeces are suitable for oviposition only when they are freshjas soon as there is any crust formation the faeces cease to be attractive to ovipositing female flies. It has also been shown that the flies obtain moisture and food directly from the lechwe and so the flies have to be mobile and capable of following the lechwe from place to place and in this order the relationship is maintained between the two.
Biology (Animal)