NRU :: Browsing by Author "Malinga, Geoffrey M."

Browsing by Author "Malinga, Geoffrey M."

Now showing 1 - 20 of 29

Active restoration facilitates bird community recovery in an Afrotropical rainforest
(Biological Conservation, 2016) Latja, Pirita; Valtonena, Anu; Malinga, Geoffrey M.; Roininen, Heikki
Active restoration of rainforests is essential in enhancing the recovery of biodiversity in many tropical regions suffering from deforestation. However, the value of actively restored rainforests for birds is still relatively poorly understood because of the short history of active restoration programs. Here, we studied the recovery of bird communities in Kibale National Park, Uganda.Wesampled birds along a restoration gradient consisting of six restoration areas (3–16 years old) and used five primary forests as reference areas. We found that bird community compositions changed in an orderly fashion along the restoration gradient. The abundance of arboreal insectivore frugivores and forest specialists increased, while that of foliage-gleaning insectivores, granivores and forest visitors decreased towards older sites. The similarity of the bird communities of the restored forests to those of the nearby primary forests increased linearly with time. If this recovery rate is extrapolated to the future, the bird communities could reach a pre-disturbance state after only approximately 20 years of active restoration. However, previous studies have shown that recovery is typically a non-linear process, and the time needed for bird communities to recover is more likely longer than this. Nevertheless, our study provides evidence that bird communities benefit from active rainforest restoration after human-induced deforestation.
Apparent density, trypanosome infection rates and host preference of tsetse flies in the sleeping sickness endemic focus of northwestern Uganda
(BMC Veterinary Research, 2021) Opiro, Robert; Opoke, Robert; Angwech, Harriet; Nakafu, Esther; Oloya, Francis A.; Openy, Geoffrey; Njahira, Moses; Macharia, Mercy; Echodu, Richard; Malinga, Geoffrey M.
African trypanosomiasis, caused by protozoa of the genus Trypanosoma and transmitted by the tsetse fly, is a serious parasitic disease of humans and animals. Reliable data on the vector distribution, feeding preference and the trypanosome species they carry is pertinent to planning sustainable control strategies. Methodology: We deployed 109 biconical traps in 10 villages in two districts of northwestern Uganda to obtain information on the apparent density, trypanosome infection status and blood meal sources of tsetse flies. A subset (272) of the collected samples was analyzed for detection of trypanosomes species and sub-species using a nested PCR protocol based on primers amplifying the Internal Transcribed Spacer (ITS) region of ribosomal DNA. 34 blood-engorged adult tsetse midguts were analyzed for blood meal sources by sequencing of the mitochondrial cytochrome c oxidase 1 (COI) and cytochrome b (cytb) genes. Results: We captured a total of 622 Glossina fuscipes fuscipes tsetse flies (269 males and 353 females) in the two districts with apparent density (AD) ranging from 0.6 to 3.7 flies/trap/day (FTD). 10.7% (29/272) of the flies were infected with one or more trypanosome species. Infection rate was not significantly associated with district of origin (Generalized linear model (GLM), χ2 = 0.018, P = 0.895, df = 1, n = 272) and sex of the fly (χ2 = 1.723, P = 0.189, df = 1, n = 272). However, trypanosome infection was highly significantly associated with the fly’s age based on wing fray category (χ2 = 22.374, P < 0.001, df = 1, n = 272), being higher among the very old than the young tsetse. Nested PCR revealed several species of trypanosomes: T. vivax (6.62%), T. congolense (2.57%), T. brucei and T. simiae each at 0.73%. Blood meal analyses revealed five principal vertebrate hosts, namely, cattle (Bos taurus), humans (Homo sapiens), Nile monitor lizard (Varanus niloticus), African mud turtle (Pelusios chapini) and the African Savanna elephant (Loxodonta africana). Conclusion: We found an infection rate of 10.8% in the tsetse sampled, with all infections attributed to trypanosome species that are causative agents for AAT. However, more verification of this finding using large-scale passive and active screening of human and tsetse samples should be done. Cattle and humans appear to be the most important tsetse hosts in the region and should be considered in the design of control interventions.
Artificial diets determine fatty acid composition in edible Ruspolia differens (Orthoptera: Tettigoniidae)
(Journal of Asia-Pacific Entomology, 2018) Rutaro, Karlmax; Malinga, Geoffrey M.; Opoke, Robert; Lehtovaara, Vilma J.; Omujal, Francis; Nyeko, Philip; Roininen, Heikki; Valtonen, Anu
There are increasing interests in rearing edible insects in Africa, but information on how the feeds modify their fatty acids is largely lacking. In this work, the influence of artificial diets on the fatty acid contents and composition in the edible Ruspolia differens (Serville, 1838), in Uganda was assessed. R. differens was reared on the mixtures of six gradually diversified diets of two, three, four, six, eight and nine feeds. The diets were formulated from rice seed head, finger millet seed head, wheat bran, superfeed chicken egg booster, sorghum seed head, germinated finger millet, simsim cake, crushed dog biscuit pellet and shea butter. Fatty acid methyl esters were prepared using direct transesterification method, and analysed using gas chromatography. The contents of saturated, monounsaturated and polyunsaturated fatty acid differed significantly among the diets. The more diverse diets resulted in increased content of the polyunsaturated fatty acids. The n6:n3 ratio differed significantly among the diets and between the sexes, with R. differens fed on the four-feed diet having a higher n6:n3 ratio than those fed on other diets. Also, the fatty acid composition differed significantly among the diets, and diet diversification corresponded with the proportions of polyunsaturated fatty acids, especially linoleic acid. Overall, our results demonstrate that higher levels of essential fatty acids can be achieved by rearing R. differens on highly diversified diets. These findings are important in informing the design of future mass-rearing program for this edible insect
Bottom-up manipulations alter the community structures of galling insects and gall morphs on Neoboutonia macrocalyx trees in a moist tropical rainforest
(Agricultural and Forest Entomology, 2014) Malinga, Geoffrey M.; Valtonen, Anu; Nyeko, Philip; Roininen, Heikki
The effects of bottom-up forces on the community structure of tropical insect gallers and within species variation in gall morphotype assemblages are not well understood. We tested the roles of increased nutritional quality and density of host plants with respect to structuring the galling insect communities and gall morphotype assemblages on Neoboutonia macrocalyx trees in Uganda. Plant nutritional quality and resource concentration were manipulated with four levels of fertilization and the group size of trees, respectively. After applying these treatments in May 2011, gallers established naturally on experimental replicates. Fivemonths later, we sampled gallers and recorded their numbers and the different morphotypes. We analyzed the effects of treatments on the structures of galler communities and gall morphotype assemblages. We recorded 5237 individuals, representing four galler species. One species, Cecidomyiid leaf galler, was represented by three morphologically distinct galls. Fertilization, host tree density and their interactions significantly changed the structures of galler species communities and gall morphotype assemblages. The results of the present study demonstrate the important role of bottom-up factors in structuring galler communities and the gall morphotype assemblages. These changes are likely caused by differential responses of different galler species and gall morphs to plant quality or quantity changes.
Bottom‑up impact on the cecidomyiid leaf galler and its parasitism in a tropical rainforest
(Oecologia, 2014) Malinga, Geoffrey M.; Valtonen, Anu; Nyeko, Philip; Vesterinen, Eero J.; Roininen, Heikki
The relative importance of host-plant resources, natural enemies or their interactions in controlling the population of galling insects and their parasitism is poorly known for tropical gallers. In this study, we assessed the impacts of plant quality and density of host trees in regulating the densities of a galler species, the cecidomyiid leaf galler (Cecidomyiini sp. 1EJV) and its parasitoids and inquilines on Neoboutonia macrocalyx trees in Uganda. We manipulated the nutritional quality (or vigour) and the resource concentration with four levels each of fertilization and the group size of host tree. We then recorded the effects of these treatments on the growth rate and total leaf area of host plants, the density of gallers and their mortality by parasitoids and inquilines. Higher levels of fertilization and host density resulted in significantly higher total leaf area than did ambient nutrient levels, and lowest tree densities, respectively. Fertilization also caused significant change in the growth rate of leaf area. Both higher fertilization and host density caused higher density of gallers. Total leaf area was positively associated with galler density, but within galled replicates, the galled leaves were larger than the ungalled leaves. Although highest levels of fertilization and density of host trees caused significant change in the densities of parasitoids, the rate of parasitism did not change. However, tree-density manipulations increased the rate of inquilinism, but on a very low level. Our results demonstrate a trophic cascade in the tropical galler and its parasitoids as a response to bottom-up effects.
Determinants of smallholder farmers’ adaptation strategies to the effects of climate change: Evidence from northern Uganda
(Agriculture & Food Security, 2021) Atube, Francis; Malinga, Geoffrey M.; Nyeko, Martine; Okello, Daniel M.; Alarakol, Simon Peter; Okello‑Uma, Ipolto
Climate change poses a threat to the sustainability of food production among small-scale rural communities in Sub-Saharan Africa that are dependent on rain-fed agriculture. Understanding farmers’ adaptations and the determinants of their adaptation strategies is crucial in designing realistic strategies and policies for agricultural development and food security. The main objectives of this study were to identify the adaptation strategies used by smallholder farmers to counter the perceived negative effects of climate change in northern Uganda, and factors influencing the use of specific adaptation strategies. A cross-sectional survey research design was employed to collect data from 395 randomly selected smallholder farmers’ household heads across two districts by the administration of a semi-structured questionnaire. Binary logistic regression was used to analyze the factors influencing farmers’ adaptation to climate change. Results: The three most widely practiced adaptation strategies were planting of different crop varieties, planting drought-resistant varieties, and fallowing. Results of the binary logit regression model revealed that marital status of household head, access to credit, access to extension services, and farm income influenced farmers’ adoption of planting drought-resistant varieties as an adaptation strategy while access to credit, annual farm income, and time taken to market influenced adoption of planting improved seeds. Gender of household head and farm income had a positive influence on farmers’ adoption of fertilizer and pesticide use. Farming experience, farm income, and access to extension services and credit influenced farmers’ adoption of tree planting. Household size, farming experience, and time taken to market had positive influence on the use of fallowing, while size of land cultivated significantly influenced farmers’ planting of different crop varieties as an adaptation strategy. Conclusion: Findings of the study suggest there are several factors that work together to influence adoption of specific adaptation strategies by smallholder farmers. This therefore calls for more effort from government to strengthen the provision of agricultural extension services by improving its climate information system, providing recommended agricultural inputs and training farmers on best agronomic practices to enhance their holistic adaptation to the effect of climate change.
Developing Mass Egg-Laying Medium for the Edible Ruspolia differens (Orthoptera: Tettigonidae)
(Journal of Economic Entomology, 2019) Malinga, Geoffrey M.; Lehtovaara, Vilma J.; Valtonen, Anu; Nyeko, Philip; Roininen, Heikki
The edible katydid, Ruspolia differens (Serville), is an economically and nutritionally important insect species that is common and widespread in Africa. Currently, there are aims to develop mass-rearing methods suitable for this species, but a critical first step would require a suitable oviposition medium to ensure economic and easy production of eggs with high hatchability. The objective of the present study was to determine the oviposition preference and egg hatchability in different oviposition media. Based on preliminary testing of a wide range of different materials, two oviposition media, namely, artificial (folded plastic cloth) and natural medium (leaf sheath of Pennisetum purpureum Schumach attached to a stem), were selected for a detailed experiment. A two-choice laboratory experiment was conducted in which R. differens females were able to select between the folded plastic cloth (one side covered with short fleece) and a leaf sheath of P. purpureum (wrapped in polyester fiber). The results show that R. differens laid almost three times more eggs on the plastic cloth (mean ± SE, 169.3 ± 18.0) than on the natural substrate, P. purpurem (69.0 ± 13.9). However, the hatchability (overall mean% ± SE, 56.5 ± 4.7) of eggs in the two media did not differ. Folded plastic cloth, therefore, provided a more effective medium for egg laying by R. differens, and is thus a promising oviposition medium for getting natural populations to start laying eggs in future mass rearing.
The Edible Katydid Ruspolia Differens Is A Selective Feeder On The Inflorescences And Leaves Of Grass Species
(Entomologia Experimentalis et Applicata, 2018) Valtonen, Anu; Malinga, Geoffrey M.; Junes, Petra; Opoke, Robert; Lehtovaara, Vilma J.; Nyeko, Philip; Roininen, Heikki
Ruspolia differens (Serville) (Orthoptera: Tettigoniidae, Conocephalinae) (its common names including ‘African edible bush-cricket’, ‘edible grasshopper’, and ‘nsenene’) is an important source of food for humans in East Africa, but its ecology and biology are poorly understood. We explored the host plants of R. differens with a series of no-choice and multiple-choice laboratory experiments using 18 local common grass and sedge species in Uganda. In no-choice experiments, the degree of acceptance differed significantly among the studied plant species, but in only three species were leaves rejected and in one species were inflorescences rejected. The pattern of acceptance among plant species was different in the local vs. swarming populations. Leaves were generally more accepted by the local population, whereas inflorescences were generally more accepted by the swarming population. Both leaves and inflorescences were more readily accepted by males than by females. According to the multiple-choice experiments, R. differens preferred inflorescences over leaves. Our results demonstrate that R. differens is a facultatively oligophagous grass-specialist, which has a clear preference for certain grass or sedge species (especially inflorescences), but it accepts many host plants if the preferred ones are not available. To preserve viable natural populations of R. differens in East Africa in the long term, our results draw special attention to the availability of grasslands where accepted and preferred host plants are available year-round.
Entry Grades and the Academic Performance of University Students: A Review of Literature
(Education Quarterly Reviews, 2021) Aciro, Rosalba; Onen, David; Malinga, Geoffrey M.; Ezati, Betty A.; Openjuru, George L.
Universities world over mostly base their decisions to admit their new students on the applicant’s pre-university academic results. However, there is yet no concrete evidence that the students’ pre-university academic accolades determine their performances at university level. In this article, we explored the findings of earlier studies that examined the relationships between entry grades and the academic performance of university students. The study was undertaken to collate the literature on the relationships between the students’ entry grades and their university academic performance in order to validate earlier assertions, if any, as well as to identify opportunities for further research in this field. During the study, we carried out a systematic review of 59 articles that we drew from different online electronic databases including, among others, the Free Scientific Publication, the Worldwide Science.org, and the Directory of Open Access Journals (DOAJ). The majority of these reviewed studies were drawn from America and Europe. Only a few of them were conducted in Asia, Latin America and Africa. Of the 59 reviewed articles, only 53 of them met our inclusion criteria and our key findings showed, among others, that out of the 53 reviewed articles, 26, 4 and 13 of them revealed the existence of positive, negative, and mixed correlations respectively between the entry grades and the academic performance of university students. The remaining 10 articles, however, did not reveal any significant correlations between the two variables; instead, they alluded to the existence of difference in these relationships between male and female students; thus, suggesting for the need for affirmative action schemes. Overall, the study revealed that there is yet no consensus over whether preuniversity academic performances of students predict their performances at university level; thus, indicating the need for further research in this field.
An ethnobotanical study of plants used for the treatment of malaria in Budondo sub-county, Eastern Uganda
(Ethnobotany Research and Applications, 2020) Malinga, Geoffrey M.; Baana, Kalori; Rutaro, Karlmax; Atube, Francis; Opoke, Robert; Opika-Opoka, Hector; Oryema, Christine
Malaria is a leading cause of morbidity and mortality in most developing countries, and in Uganda over 95% of the country is endemic with malaria. Given the increasing widespread resistance to current drugs, the use of herbal medicines is seen as a sustainable solution to malaria treatment. This study documented medicinal plants that are traditionally used for the treatment of malaria in Budondo sub-county, Eastern Uganda. Methods: The ethnobotanical survey was conducted between December 2017 to January 2018. A total of 273 household members were interviewed on knowledge and use of anti-malarial plants, using semistructured questionnaires administered in five parishes of Budondo sub-county. Voucher specimen of each plant species were preserved at the Makerere University herbarium, Uganda. Results: Overall, 97.5% of the respondents had knowledge regarding the plants used to treat malaria. A chi-square analysis shows a significant association between respondents’ knowledge regarding antimalarial plants and gender (p-value =0.008) and occupation (p-value =0.025) but not with age (p-value =0.379), educational status (p-value =0.066), average monthly income (p-value =0.419), and religious affiliation (p-value =0.064) of respondents. A total of 37 plant species, belonging to 25 plant families were used to treat malaria. The most cited plant was Vernonia amygdalina Delile (64.8%), followed by Aloe vera (L.) Burm.f. (41.9%), Callistemon citrinus (Curt.) Stapf (29.3%), Mormodica feotida Schumach (22.0%), Cyphostemma adenocaule (A. Rich) wild & Drumm. (16.1%) and Eucalyptus globulus Labill. (15.4%). Among the plant parts, stem bark (99.6%) and leaves (90.8%) were the most frequently used. The habits of the plants encountered were shrub, tree, herb, rhizomes and climber. The commonest modes of preparation included boiling in water, squeezing fresh leaves, crushing and pounding, and chewing. Oral route/drinking was the most common mode of administration, followed by steam inhaling of vapours from the aqueous extracts and skin bathing. Conclusion: The present study shows that the people living in Budondo sub-county traditionally use diverse flora to treat malaria. Further investigations are required to evaluate the potential toxicological effects and to isolate the active components of the reported plants whose antimalarial activities have not been investigated which could be developed into effective, safe and affordable anti-malarial medicines in the future.
Ethnobotanical survey of plants locally used in the control of termite pests among rural communities in northern Uganda
(CABI Agriculture and Bioscience, 2022) Okori, Betty C.; Oryema, Christine; Opiro, Robert; Amos, Acur; Obici, Gilbert I.; Rutaro, Karlmax; Malinga, Geoffrey M.; Sande, Eric
Termites are the most destructive pests in many agricultural and forest plantations in Uganda. Current control of termites mostly relies on chemical pesticides. However, the adverse effects of chemical insecticides necessitate the need to search for and popularize the usage of environmentally safer options. Plants represent one of the most accessible resources available for termite control by communities in Uganda. However, limited documented information exists for their contribution in the management of except through verbal sharing. This study aimed at assessing the communities’ knowledge about plants traditionally used in controlling termites among selected communities in Apac District, northern Uganda. Method: An ethnobotanical survey was conducted between November 2016 and February 2017 in 12 randomly selected villages in the sub counties of Apac and Ibuje of Apac District, northern Uganda. Open-ended questionnaire interviews were used to gather ethnobotanical and sociodemographic data. A total of 381 indigenous people were interviewed [male, 281 (73.8); female, 100 (26.2)]. Data were analysed using descriptive statistics and Informant Consensus Factor (ICF), and the relative frequency of citation (RFC) was determined. Results: Overall, 70.9% of the respondents were knowledgeable about plants used for control of termites. There was a significant association between respondents’ knowledge of pesticidal plants with age and gender but not with education status. A total of 11 plant species belonging to eight families were identified to be in use for control of termites in Apac. Solanaceae, Eurphorbiaceae and Asteraceae were the most represented families with two species each, while the rest of the families had only one species mentioned. According to the relative frequency of citation (RFC), Kigelia africana (Lam.) Benth. (RFC = 0.43), Vernonia amygdalina Delile (0.18) and Tithonia diversifolia (Hemsl.) A. Gray (0.10) were the most used in the control of termites in the study area. Fruits (45.9%) and leaves (29.2%) were the most used plant parts. Squeezing, crushing and chopping of the plant materials were the most popular methods of preparation and water extract was the commonest mode of formulation of plant parts. Conclusions: The study has shown that rural populations of the targeted localities possess indigenous knowledge on anti-termitid plants. However, screening is urgently needed to validate their bioactivity and to determine the bioactive constituents responsible for killing the invertebrates in pest management. Furthermore, simple methods for local propagation and cultivation are needed to ensure a sustainable supply of termicidal plant biomass.
Farmers’ perceptions of climate change, long‑term variability and trends in rainfall in Apac district, northern Uganda
(CABI Agriculture and Bioscience, 2022) Atube, Francis; Malinga, Geoffrey M.; Nyeko, Martine; Okello, Daniel M.; Mugonola, Basil; Omony, George William; Ipolto, Okello‑Uma
Climate change poses severe threats to smallholder farmers’ agricultural livelihoods and food security in Sub Saharan Africa. Understanding long-term rainfall trends of variability and extremes at local scales and perceptions regarding long-term changes in climate variables is important in planning appropriate adaptation measures to climate change. This paper examines the perception of farmers in Apac district regarding long-term changes in climate variables and analyzes the trend of occurrence in seasonal and annual rainfall in Apac district, northern Uganda. A cross-sectional survey design was employed to collect data on farmers’ perceptions regarding long-term changes in climate from 260 randomly selected smallholder farmers’ households across two sub-counties in Apac district by administering semi-structured questionnaires in February 2018. Monthly rainfall data sets from the Uganda Meteorological Authority (UMA) for the period 1980 to 2019 for Apac district were also used to analyze trends of occurrences in seasonal and annual rainfall in the study area. The non-parametric Sequential Mann–Kendall (SMK) tests were employed at a 5% significance level to detect mean seasonal rainfall trends and abrupt change points. Results: The majority of the respondents (87%) perceived a decrease in precipitation over the past 39 years. The plot of forward regression u(ti) values and backward regression u’(ti) values showed interactions indicating rainfall trends, rainfall lower and upper limits and abrupt change points in the different cropping seasons. Analysis of historical series of mean monthly and annual rainfall showed an abrupt change in rainfall in March, April, May (MAM) season in 1982. Although the September, October and November (SON) season did not show a significant abrupt change, there was a significant (p < 0.05) increase in rainfall above the upper limit from 1994 to date. Conclusion: The mean seasonal rainfall for MAM and SON cropping seasons in Apac district were highly variable from different time points within the past 39 years (1980–2019), while June, July, and August (JJA) did not realize a significant change in rainfall within the same study period that the two cropping seasons (MAM and SON) in the district experienced remarkable variations in rainfall. This, therefore, provides a basis for the government to strengthen the provision of an effective climate tailored agricultural advisory service to aid farmers’ adaptation planning at the local level and to assist smallholder farmers and land-use managers in developing effective adaptation management strategies to the effects of climate change.
The fatty acid composition of edible grasshopper Ruspolia differens (Serville) (Orthoptera: Tettigoniidae) feeding on diversifying diets of host plants
(Entomological Research, 2018) Rutaro, Karlmax; Malinga, Geoffrey M.; Lehtovaara, Vilma J.; Opoke, Robert; Valtonen, Anu; Kwetegyeka, Justus; Nyeko, Philip; Roininen, Heikki
Ruspolia differens (Serville) (Orthoptera: Tettigoniidae) is a highly valued edible grasshopper species in Africa. However, the effects of plant diets on lipid content and fatty acid composition of R. differens are not well understood. We tested the effects of four diets on the total lipid content and fatty acid composition of R. differens. Sixth instar nymphs of R. differens were reared on one, and mixtures of two, three, and six natural plant inflorescences. Individuals collected from the field constituted a control treatment.We extracted lipids and analyzed the fatty acidmethyl esters using gas chromatography–mass spectrometry. We analyzed if the total lipid content, body weight, and fatty acid composition differed among diets and between the sexes using two-way ANOVAs and a PERMANOVA model, respectively. The total lipid content and weight of R. differens did not differ among the diets. The nine common fatty acids were palmitic (mean across treatments, 26%), oleic (22%), palmitoleic (18%), linoleic (13%), stearic (7%), myristic (6%), myristoleic (4%), α-linolenic (2%) and arachidic acid (1%). The composition of fatty acids and the proportion of essential fatty acids significantly differed among the diets. The proportion of essential fatty acids was highest in the control treatment (21%) but low in less diversified (one to three feed) diets (12–13%). This study demonstrates that the fatty acid composition in R. differens can be influenced through diet. Thus, with dietary manipulations, using local plants in Africa, it is possible to produce R. differens with preferred high quality essential fatty acids for human consumption.
Fatty acid content and composition in edible Ruspolia differens feeding on mixtures of natural food plants
(BMC Research Notes, 2018) Rutaro, Karlmax; Malinga, Geoffrey M.; Lehtovaara, Vilma J.; Opoke, Robert; Nyeko, Philip; Roininen, Heikki; Valtonen, Anu
To develop successful mass-rearing programs of edible insects, knowledge of the feeds and their influence on nutritional content is critical. We assessed the influence of natural food plants (grass inflorescences) and their mixtures on fatty acid profiles of edible Ruspolia differens. We reared neonate nymphs to adult on six dietary treatments consisting of one, and mixtures of two, three, five, six and eight plants. Results: The contents of saturated, monounsaturated and polyunsaturated fatty acids, omega-6/omega-3 ratio, and adult body weight did not differ among dietary treatments. However, the composition of fatty acids differed significantly among insects fed on six dietary treatments, but only for the rare fatty acids. Our results demonstrate that even if natural diets (grass inflorescences) do not strongly modify fatty acid contents or compositions of R. differens, when reared from neonate nymphs to adults, their n − 6/n − 3 fatty acid ratio is generally low and thus good for a healthy human diet.
Heterogeneity in the prevalence and intensity of bovine trypanosomiasis in the districts of Amuru and Nwoya, Northern Uganda
(BMC veterinary research, 2015) Angwech, Harriet; Nyeko, Jack H. P.; Opiyo, Elizabeth A.; Okello-Onen, Joseph; Opiro, Robert; Echodu, Richard; Malinga, Geoffrey M.; Njahira, Moses N.; Skilton, Robert A.
Livestock trypanosomiasis, transmitted mainly by tsetse flies of the genus Glossina is a major constraint to livestock health and productivity in the sub-Saharan Africa. Knowledge of the prevalence and intensity of trypanosomiasis is important in understanding the epidemiology of the disease. The objectives of this study were to (a) assess the prevalence and intensity of trypanosome infections in cattle, and (b) to investigate the reasons for the heterogeneity of the disease in the tsetse infested districts of Amuru and Nwoya, northern Uganda. Methods: A cross-sectional study was conducted from September, 2011 to January, 2012. Blood samples were collected from 816 cattle following jugular vein puncture, and screened for trypanosomes by HCT and ITS-PCR. A Pearson chi-squared test and logistic regression analyses were performed to determine the association between location, age, sex, and prevalence of trypanosome infections. Results: Out of the 816 blood samples examined, 178 (22 %) and 338 (41 %) tested positive for trypanosomiasis by HCT and ITS-PCR, respectively. Trypanosoma vivax infection accounted for 77 % of infections detected by ITS-PCR, T. congolense (16 %), T. brucei s.l (4 %) and mixed (T. vivax/ T. congolense/T.brucei) infections (3 %). The risk of trypanosome infection was significantly associated with cattle age (χ2 = 220.4, df = 3, P < 0.001). The highest proportions of infected animals were adult males (26.7 %) and the least infected were the less than one year old calves (2.0 %). In addition, the risk of trypanosome infection was significantly associated with sex (χ2 = 16.64, df=1, P < 0.001), and males had a significantly higher prevalence of infections (26.8 %) than females (14.6 %). Conclusion: Our results indicate that the prevalence and intensity of trypanosome infections are highly heterogeneous being associated with cattle age, location and sex.
High prevalence of Pfmdr‑1 N86 and D1246 genotypes detected among febrile malaria outpatients attending Lira Regional Referral Hospital, Northern Uganda
(BMC Research Notes, 2019) Achol, Emmanuel; Ochaya, Stephen; Malinga, Geoffrey M.; Edema, Hillary; Echodu, Richard
To determine the prevalence of Plasmodium falciparum multi-drug resistant gene-1 (Pfmdr-1) N86Y and D1246Y genotypes among febrile malaria outpatients attending Lira Regional Referral Hospital, Uganda. Results: Overall, 92.3% (n = 48/52) and 90% (n = 45/50) of the parasites detected carried the wild type alleles 1246D and N86, respectively. Only 7.7% (n = 4/52) and 10% (n = 5/50) of these P. falciparum isolates carried the Pfmdr-1 mutant alleles 1246Y and 86Y, respectively. Our results show high prevalence of wild type alleles N86 and D1246 in P. falciparum isolates from Lira Regional Referral Hospital, which could translate to a decreased sensitivity to artemetherlumefantrine. Continued monitoring of prevalence of single nucleotide polymorphisms is warranted to timely inform malaria treatment policies and guidelines.
Host plants of the non‐swarming edible bush cricket Ruspolia differens
(Ecology and Evolution, 2019) Opoke, Robert; Nyeko, Philip; Malinga, Geoffrey M.; Rutaro, Karlmax; Roininen, Heikki; Valtonen, Anu
The edible Ruspolia differens (Orthoptera: Tettigoniidae) is a widely-consumed insect in East Africa but surprisingly little is known of its host plant use in the field. We studied host plants used by non-swarming R. differens for 15 months, in central Uganda. In particular, we assessed the use of host plant species with respect to host cover in the field and host parts used by R. differens, also recording their sex, developmental stages, and colour morph. Ruspolia differens were found on 19 grass and two sedge species and they were observed predominantly (99% of 20,915 observations) on seven grasses (namely, Panicum maximum, Brachiaria ruziziensis, Chloris gayana, Hyparrhenia rufa, Cynodon dactylon, Sporobolus pyramidalis, and Pennisetum purpureum). Ruspolia differens was most frequently observed on the most common grass of each study site but P. maximum, and S. pyramidalis were used more frequently than expected from their cover in the field. Furthermore, R. differens were observed predominantly on inflorescences (97% of feeding observations) and much less frequently on the leaves (3.0%), stems (0.1%), and inflorescence stalks (0.1%) of grasses and sedges. Host use was not independent of sex, developmental stage, or colour morph. Panicum maximum was the preferred host of the youngest nymphs of R. differens. Overall, our findings indicate that a continuous supply of diverse grass resources with inflorescences is necessary for the management and conservation of wild populations of R. differens.
Identification of candidate genes associated with resistance to bruchid (Callosobruchus maculatus) in cowpea
(Plant Breeding, 2019) Miesho, Belay; Hailay, Mehari; Msiska, Ulemu; Bruno, Awio; Malinga, Geoffrey M.; Obia Ongom, Patrick; Edema, Richard; Gibson, Paul; Rubaihayo, Patrick; Kyamanywa, Samuel
Cowpea is an important legume crop widely grown in sub‐Saharan Africa for food and feed. However, it is largely challenged by bruchid, a serious storage pest resulting in losses in quantity and quality of grains. Therefore, this research was designed to contribute to the breeding of cowpea resistance to bruchid through the identification of candidate genes associated with resistance to bruchid. A total of 217 mini‐core cowpea accessions were genotyped and phenotyped for their reactions to bruchid. To determine the genomic regions linked with bruchid resistance, 41,948 polymorphic SNP markers were used. Genome‐wide association study identified 11 SNPs linked to the average number of eggs, holes, insect emergence and development period and Dobie susceptibility index. Gene search via Phytozome identified six candidate genes (Vigun08g132300, Vigun08g158000, Vigun06g053700, Vigun02g131000, Vigun01g234900 and Vigun01g201900) associated with the resistance traits. These candidate genes could be incorporated into the farmers preferred but susceptible cowpea varieties to bruchid. The SNP markers associated with the resistance traits can be used in marker‐assisted breeding for accurate and rapid screening of cowpea resistant genotypes to bruchid.
Mixed Artificial Diets Enhance The Developmental And Reproductive Performance Of The Edible Grasshopper, Ruspolia Differens (Orthoptera: Tettigoniidae)
(Applied Entomology and Zoology, 2018) Malinga, Geoffrey M.; Valtonen, Anu; Lehtovaara, Vilma J.; Rutaro, Karlmax; Opoke, Robert; Nyeko, Philip; Roininen, Heikki
Diet mixing is a common feeding habit among polyphagous insect herbivores and is believed to be advantageous for performance-related factors like growth, survival and oviposition. However, relatively little is known about the influence of artificial diet or their mixtures on the performance of edible insects. We examined the effects of artificial diet mixtures on the developmental and reproductive performance (survival, developmental time, fresh adult weight and female fecundity) of an edible grasshopper, Ruspolia differens (Orthoptera: Tettigoniidae). We raised individuals from eggs and reared newly hatched nymphs to adult stage on six different dietary treatments consisting of a single diet, and mixtures of two, three, five, six and eight artificial diets. More diversified diets resulted in shorter development time and greater adult fresh weight and female fecundity compared to the single diet or less diversified diets. Even with slight diet diversification, survival to adult stage was greatly improved. Overall, these results highlight the potential of diet mixtures in achieving maximum adult weights and female fecundity and shortening development time, information which could be used when designing mass-rearing programs for this edible grasshopper.
Performance of the African edible bush-cricket Ruspolia differens on single and mixed diets containing inflorescences of their host plant species
(Entomologia Experimentalis et Applicata, 2020) Malinga, Geoffrey M.; Valtonen, Anu; Hiltunen, Minna; Lehtovaara, Vilma J.; Nyeko, Philip; Roininen, Heikki
The African edible bush-cricket, Ruspolia differens (Serville) (Orthoptera: Tettigoniidae), is an economically valuable insect in sub-Saharan Africa. For its mass-rearing, suitable diets that can sustain its performance need to be identified. This study aimed at finding inflorescence diets of 10 host plant species and their mixtures that result in the highest R. differens production. We reared newly hatched nymphs to adults on inflorescences of single host species, and also on a gradient of five diversifying dietary mixtures consisting of one and mixtures of two, three, five, and seven host plant species. For the single host-plant diets, the developmental time was shortest on Pennisetum purpureum, Chloris gayana, and Brachiaria ruziziensis (approximately 63 days), whereas the fresh weight was highest on B. ruziziensis and P. purpureum (approximately 0.383 g). Survival was highest (>65%) on C. gayana, P. purpureum, B. ruziziensis, Setaria sphacelata, and Sporobolus pyramidalis, and lowest on Panicum maximum, Hyparrhenia rufa, Cynodon dactylon, and Paspalum scrobiculatum (<40%). With respect to diet mixtures, the developmental time was significantly shorter (on average 16 days shorter), and survival was higher, in the most diversified diets compared to the least diversified diets. The contents of polyunsaturated fatty acids (PUFA) and fatty acid composition did not differ significantly among the diets. However, the content of monosaturated fatty acids (MUFA) differed significantly among the diets and there was a significant diet*sex interaction. From the applied point of view, based on our results, for maximal weight and survival plus fast development, we recommend rearing on P. purpureum, C. gayana, B. rizuziensis, and S. sphacelata, and on dietary mixtures of inflorescences. These findings are important in designing large-scale rearing programs for this species.

Browsing by Author "Malinga, Geoffrey M."

Results Per Page

Sort Options