Effects of habitat fragmentation on food habits, intestinal parasites and aspects of reproduction among praomys delectorum sub-populations in the Taita and Kyulu hills ,Kenya
Gitonga, John Wambugu
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Due to their short life histories, small mammals are useful indicators of environmental health and fauna diversity. Despite this, little or no investigations on the effects of habitat modification on small mammals' diets in Kenya has been done. This study investigated the effect of habitat fragmentation on food habits and litter size of P. delectorum in three sub-populations of the Taita Hills and the Kyulu Hills population. Response of the forestdependant Praomys delectorum to anthropogenic disturbance in different forest patches of the Taita Hills suggests that it is an opportunistic omnivore as its population increases with increase in vegetation intergiditation. Food habits variation was assessed by comparing morphometry of the gastrointestinal tract while foetuses and placental scars were used as litter size indicators. The study also gave some information on intestinal parasites, and the histology of testes and ovary based on routine histological techniques. Total intestinal length was significantly correlated with body mass (r=0.624, P<0.001) and head plus body length (x=0.722, P<0.001), respectively. The linear response of total intestine length to head plus body length was greater ( = 0.642, t = 5.951, P < 0.001) than that of body mass ( = 0.214 t=1.983, P=0.053) suggesting it is a better covariate in removing size erect. A significant difference (F=2.883*, P= 0.043) in the relative length of large intestine was noted among the sub-populations suggesting variation in food quality. There was no significant difference in litter size ( F3,15 = 0.126 ns P =0.943) among the different sub-populations. Prominent nuclei of primary spermatocytes in the seminiferous tubules of both abdominal and scrotal testes were indicative of spermatogenesis though germ cells organization was clearer in scrotal testes. The ovary of female with vagina closed lacked corpora lutea which were nonetheless observed in the ovary of females with vagina open though developing Graafian follicles were observed in both. Thus vaginal condition is a good indicator of reproductive status in this species. Percentage prevalence of intestinal parasite conformed to the trends of anthropogenic disturbance among the Taita Hills sub-populations although Kyulu Hills population had the highest (63.16%) infestation. Information of this kind is essential in building a complete biological picture of Praomys delectorum like litter size and the intestinal parasites that infect it. Praomys delectorum display a digestive tract adaptation suggestive of an opportunistic feeder. This may have been due to change in food habits that could be associated with transformation of natural habitat into fragments.
- MST-Zoological Sciences