SPECIES COMPOSITION AND GENETIC STRUCTURES OF GLOSSINA POPULATIONS IN SELECTED NIGERIAN NATIONAL PARKS
SPECIES COMPOSITION AND GENETIC STRUCTURES OF GLOSSINA POPULATIONS IN SELECTED NIGERIAN NATIONAL PARKS
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Date
2018-10
Authors
SHAIDA, Stephene Saikiu
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Abstract
A study of population genetic structure of tsetse flies (Glossina spp), vectors of Human and Animal trypanosomiasis, was undertaken in order to increase our understanding on the distribution and dynamics of tsetse fly populations in Nigeria. Tsetse flies were collected in selected four Nigeria National Parks/Game Reserve namely, Kainji Lake National Park, Old Oyo National Park, Cross River National Park, Yankari Game Reserve and a highly tsetse infested agropastoral area within the Federal Capital Territory Abuja at ijah Gwari, and examined using Cytochrome Oxidase C SU1 (CO 1), Internal transcribed spacer-1(ITS-1) sequences and geometric wing morphometrics. Flies were sampled using standard biconical traps, while ambient temperature and relative humidity conditions were recorded with a whirling hygrometer and co-ordinates of sampled locations and trapping points were recorded with GPS device for geo-referencing. A total of 1891 tsetse flies were collected comprising, Glossina tachinoides (1050, 55.53%), Glossina palpalis palpalis (568, 30.04%), Glossina morsitans submorsitans (270, 14.23%) and Glossina fusca (3, 0.16%). Analysed data showed significant difference (χ2 (4) = 1375.417, p ˂ 0.001) in the relative abundance of Glossina spp. per sampled location, whereas pairwise comparison showed no significant difference (p = 1.000) in the relative abundance of Glossina spp. between Cross River and Ijah Gwari sampled locations. Apparent densities of Glossina populations were significantly different (χ2 (4) = 20.500, p < 0.001) per sampled location. Pairwise comparison however, showed that Old Oyo, Yankari, and Kainji locations had comparatively high apparent densities of Glossina spp. Male and female fly ratios were significantly different (χ2 (1) = 4.000, p =0.046) with higher proportion of male flies caught than females in some but not all species in all regions sampled. The composition of Glossina species in the sampled locations showed no significant association (χ2 (12) = 2134.106, p > 0.001), as well as no significant difference (t = -1.580, p 0.133 > α = 0.05) in tsetse catches in relation to ambient temperature and relative humidity conditions was observed in Yankari Game Reserve. Significant difference (t = -10.633, p =0.000 ˂ α =0.05) in tsetse catches in relation to ambient temperature and relative humidity conditions was observed in Kainji Lake National Park, (t = -36.290, p = 0.000 ˂ α = 0.05) in Old Oyo National Park, (t = -18.939, p = 0.000 ˂ α = 0.05) in Cross River National Park and (t = -4.613, p = 0.01 ˂ α = 0.05) in Ijah Gwari. No significant correlations between tsetse catches and ambient temperature and relative humidity conditions were observed in most of the trapping locations visited, suggesting that the distribution of flies across the sampled locations were probably influenced by other environmental factors than climatic conditions alone.
Tenerity phenomenon showed significant difference (χ2 (4) = 20.500, p < 0.001) in the proportion of teneral and non teneral flies amongst the four Glossina species caught, with the proportion of teneral flies in each Glossina species being significantly higher than the non-teneral flies, except in G. fusca in which there was no significant difference between the number of teneral and non-teneral flies caught. Pairwise comparison showed that Yankari Game Reserve, Old Oyo and Kainji Lake National Parks had comparable tenerity of Glossina species. Five Glossina spp. for which no information on their COI sequences is available on the Genbank, could not be identified molecularly using phylogenetic analysis. However, the study demonstrated the splitting of G. p. palpalis populations into two major groups, a West African Clade (WAC) and a Central Africa Clade (CAC), with the convergence zone of the two major groups (WAC and CAC) found co-existing sypatrically in the region of Cross River National Park at the Nigerian-Cameroonian border area. While the ITS-1 regions of the G. p. palpalis subpopulations did not show any differences, the geometric wing morphometrics showed a sex dependent shape dimorphism in 41 flies examined from Dodeo region in Cameroon. Since the COI sequences have clearly revealed the splitting of Glossina palpalis palpalis populations into two major groups, the question requiring answer is whether the two groups of G. p. palpalis identified in this study can interbreed and if so are the vectorial capacities of the two groups of flies the same, these need to be investigated. This is even so as the isolation status of flies in the National Parks need to be investigated especially as migration of other flies into cleared areas may hinder the success of tsetse control using SIT, whereas limited migration may lead to success.
It is concluded that information generated from this study, would aid the choice of effective anti-tsetse management approaches in the country’s National Parks using a component of the sterile insect technique (SIT) as being advocated by the Pan African Tsetse and Trypanosomiasis Eradication Campaign (PATTEC).
Description
A THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES AHMADU BELLO UNIVERSITY, ZARIA IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE AWARD OF DOCTOR OF PHILOSOPHY IN ZOOLOGY, DEPARTMENT OF ZOOLOGY FACULTY OF LIFE SCIENCES, AHMADU BELLO UNIVERSITY, ZARIA NIGERIA
Keywords
SPECIES COMPOSITION,, GENETIC STRUCTURES,, GLOSSINA POPULATIONS,, NIGERIAN,, NATIONAL PARKS,