Department of Biology

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Browsing Department of Biology by Author "Malinga, Geoffrey M."

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    Heterogeneity in the prevalence and intensity of bovine trypanosomiasis in the districts of Amuru and Nwoya, Northern Uganda
    (Biomedical Central- 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.; and Skilton, Robert A.
    Background: 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 (χ 2 = 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 (χ 2 = 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
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    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, special issue: insect production, 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 eco nomically 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 and fatty acid composition did not differ significantly among the diets. However, the content of monounsaturated fatty acids 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. ruziziensis, and S. sphacelata, and on dietary mixtures of inflorescences. These findings are important in designing large-scale rearing programs for this species.
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    Recovery of fruit-feeding butterfly communities in Budongo Forest Reserve after anthropogenic disturbance
    (Forest Ecology and Management, 2021-04-07) Oloya, Joseph; Malinga, Geoffrey M.; Nyafwono, Margaret; Akite, Perpetra; Nakadai, Ryosuke; Holm, Sille; Valtonen, Anu
    Understanding of how biodiversity can recover after anthropogenic disturbances, such as selective logging, is important for planning conservation strategies for tropical forests and for more sustainable timber harvest re gimes. However, the knowledge of insect community compositions in regenerating logged forests is still limited, especially in the Afrotropics. Here, we evaluated the recovery patterns of fruit-feeding butterfly communities in four different-aged secondary forest compartments and one primary forest compartment in the Budongo Central Forest Reserve, Uganda. In each compartment, butterflies were sampled monthly for five consecutive months in 2017 using traps baited with fermented bananas. A total of 3,778 individuals, representing 82 species (78 identified at the species level and four morphogroups) were recorded. The fruit-feeding butterfly community composition differed among forest compartments and study months. Fruit-feeding butterfly communities of the oldest 72-year-old secondary forest compartment were similar to the primary forest compartment. In the younger secondary forest compartments the seasonal variation was large; especially the communities of the “core” rainy season months were distinct from the communities in primary and oldest secondary forest. The majority of individuals captured from both primary and secondary forests represented forest-dependent species. Primary forests are irreplaceable for preserving the diversity of tropical forests in the long-term. Nevertheless, our study demonstrates that selective logging can allow fruit-feeding butterfly community composition to recover if enough time (>70 years) is allowed for recovery.