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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Date
2011-03-31
Authors
Muntemba, D. C
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Abstract
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.
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Biology (Animal)