Bottom-up impact on the cecidomyiid leaf galler and its parasitism in a tropical rainforest.

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.

Promoting insect farming and household consumption through agricultural training and nutrition education in Africa: A study protocol for a multisite cluster-randomized controlled trial.

BACKGROUND: Edible insects are a sustainable source of high-quality animal protein. Insect farming is gaining interest globally, particularly in low-income countries, where it may provide substantial nutritional and economic benefits. To enhance insect farming practices in Africa, new farming systems are being developed. However, knowledge on how to best promote uptake of these systems is lacking. This study aims to fill this gap by investigating the effectiveness of educational interventions in promoting insect farming for household consumption in Africa. METHOD: The study is designed as a multi-site randomized controlled trial to evaluate the impacts of agricultural training alone or in combination with nutrition education on the adoption of insect farming in Ghana, Kenya and Uganda. In each of the three countries, ninety-nine villages are randomly assigned to one of three arms: two intervention arms and a control arm with no interventions. Focusing on production (P), the first intervention arm covers agricultural training on insect farming combined with provision of insect production starter kits. Focusing on both production and consumption (PC), the second intervention arm involves the same intervention components as treatment P plus additional nutrition education. The impacts of the interventions are measured by comparing baseline and endline data collected one year apart. Primary outcomes are adoption of insect farming and consumption of the farmed insects. DISCUSSION: Understanding the drivers and impacts of novel agricultural practices is crucial for transitioning to sustainable food systems. The current project is the first to investigate how educational interventions promote insect farming for household consumption in low-income countries. The results will contribute evidence-based knowledge to support sustainable development through insect farming in Africa. TRIAL REGISTRATION: The protocol is registered in the American Economic Association registry for randomized control trials with registration number AEARCTR-0009996. Initial registration date: 02 September 2022, last updated 17 May 2023.

Growth and Reproductive Performance of Edible Grasshopper (Ruspolia differens) on Different Artificial Diets.

Ruspolia differens (Serville) (Orthoptera: Tettigoniidae), also known as the 'edible grasshopper', 'African edible bush-cricket', and 'nsenene', is regarded as one of the most promising edible insect species that can be used for food, particularly in Sub-Saharan Africa. However, there is insufficient information on suitable diets and their effects on survival, adult weight, fecundity, and developmental time of this species, which are preconditions for large-scale production. In this study, we experimentally evaluated the effects of 12 diets (wheat bran, rice seed head, finger millet seed head, soya bran, maize bran, fresh maize comb, millet flour, chicken feed egg booster, simsim cake, sorghum seed head, powdered groundnut, and germinated finger millet), that are known to be accepted by R. differens, on their growth and reproductive parameters. The survival rate, developmental time, and adult weight varied considerably on the various diets. The highest nymphal survival rates, shortest development times, and highest adult weights were recorded for both sexes when fed fresh maize comb and germinated finger millet diet. Lifetime fecundity of females fed on germinated finger millet also was, on average, more than twice higher compared to other diets. The present study demonstrated that relatively inexpensive and locally available germinated finger millet, fresh maize seed (at the silking stage on the comb), sorghum seedhead, and finger millet seedhead could be successfully used to rear and sustain populations of R. differens. Our findings contribute to the future design of an effective mass-rearing system for this economically important edible insect.

Developing Mass Egg-Laying Medium for the Edible Ruspolia differens (Orthoptera: Tettigonidae).

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.

Host plants of the non-swarming edible bush cricket Ruspolia differens.

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.

Physicochemical composition of Tamarindus indica L. (Tamarind) in the agro-ecological zones of Uganda.

The relationships between the physicochemical composition of Tamarindus indica pulp and seeds, and agro-ecological zones and land use types were assessed in Uganda. The objective was to determine the relationship between the physicochemical composition, agro-ecological zones, and land use types. The samples were processed by manually depulping the T. indica pods, sun-drying the pulp and seeds, and grinding into powder. The powdered samples were analyzed for ß-carotenoids, vitamin C (ascorbic acid), calorific value, crude oil, acid, and peroxide values. Data were analyzed using ANOVA in the general linear model (GLM). Principal component analysis (PCA) was used to relate the physicochemical properties to the agro-ecological zones and land use types. There were significant differences (p ≤ .05) in the physicochemical composition variables between agro-ecological zones and land use types. Land use types showed strong correlations with physicochemical properties while agro-ecological zones did not show correlations. The results show that in terms of general properties, T. indica pods provide a valuable, rich, and exceptional source of vitamin C, compared to many widely consumed indigenous and conventional fruits and vegetables. The pods from land use types characterized by natural habitats had relatively more nutrient levels than the land use types influenced by anthropogenic activities.

Fatty acid content and composition in edible Ruspolia differens feeding on mixtures of natural food plants.

OBJECTIVES: 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.

Knowledge, attitudes and practices in tamarind (Tamarindus indica L) use and conservation in Eastern Uganda.

BACKGROUND: Tamarindus indica L is one of the indigenous fruit tree species that traditionally contributes to food security and ecosystem stability in sub-Saharan Africa. We hypothesized that the indigenous people of Eastern Uganda have used T. indica for generations and developed practices that promote its conservation and therefore we expected that they possess an elaborate indigenous knowledge (IK) system and that most of them have planted the species. The aim of this study was to assess the influence of IK, attitudes and practices on the use and conservation of T. indica. METHODS: A cross sectional survey was conducted in two districts purposively selected from the T. indica natural range. Focus group discussions, key informant interviews, semi-structured interviews and observation were used to collect data. Data was processed using qualitative analytical methods. RESULTS: Tamarindus indica was highly valued by the majority of the population. Tamarindus indica was used for food, medicinal, cultural, social, environmental amelioration and income generation purposes. The population possessed a high level of IK about T. indica evidenced by 18 categories of uses and multiple modes of use. Fruit pulp was the most commonly used tamarind product. Relative frequency of citation of the different uses provides insight into usage levels and IK possessed. The communities' food and medicinal uses concurred with scientific reports of health benefits of consuming T. indica. Approximately half of respondents had T. indica on their compounds or homegardens (53%). Fifty two percent of the tamarind population was self-propagated, 45% were planted while the propagation history for the remaining 3% was not known. Constraints towards planting T. indica included limited land, long maturation period and low monetary value. Fifty three percent of those who were growing T. indica did not carry out any silvicultural practices. The majority of T. indica encountered (87%) was intercropped with other crops or trees. Several beliefs and taboos regarding T. indica persist. CONCLUSION: Tamarindus indica has a high use value in the study area evidenced by multiple uses. Indigenous knowledge and uses concurred with scientifically proven nutritional and medicinal attributes of T. indica in literature which is significant given current trends towards affordable functional foods. The high level of IK has not translated into high rates of planting T. indica. There is need to encourage value-addition so as to maximize T. indica benefits and enhance conservation.

Mineral composition of Tamarindus indica LINN (tamarind) pulp and seeds from different agro-ecological zones of Uganda.

Mineral composition of dry Tamarindus indica LINN pulp and seeds was evaluated on samples collected from three different agro-ecological zones of Uganda (Lake Victoria Crescent, and Eastern and West Nile). The objective of the study was to evaluate the mineral composition of T. indica pulp and seed samples from across Uganda's different agro-ecological zones and land use types. Separately grounded samples of T. indica pulp and seeds were analyzed for Zn, Fe, Mg, P, Na, K, and Ca. The univariate analysis of variance in the General Linear Model was used to compare differences in mineral composition. Treatment means were separated using Least Significant Difference (LSD) in Post Hoc Tests. The results showed that there were significant differences (p ≤ 0.005) in mineral composition levels of T. indica pulp and seed samples between the different agro-ecological zones with the exception of P and Na (for pulp). The T. indica pulp and seeds samples from the Lake Victoria Crescent zone and wild land use type had generally higher mineral levels than T. indica samples from other agro-ecological zones and different land use types. As mineral composition levels were generally higher in the seed than the pulp samples, consumption of T. indica seeds should be promoted. There is also need to conserve individual species both on-farm and in the wild population, but T. indica mineral concentrations (both pulp and seeds) were higher in the samples from the wild population, making them good for human and animal diets.

Does farm worker health vary between localised and globalised food supply systems?

Significant environmental benefits are claimed for local food systems, but these biophysical indicators are increasingly recognised as inadequate descriptors of supply chain ethics. Social factors such as health are also important indicators of good practice, and are recognised by the organic and local food movements as important to the development of rounded sustainable agricultural practices. This study compared the self-reported health status of farm workers in the United Kingdom, Spain, Kenya and Uganda who were supplying distant markets with fresh vegetables. Workers on Kenyan export horticulture farms reported significantly higher levels of physical health than did Kenyan non-export farm workers and workers in the other study countries. Mean health levels for farm workers in the United Kingdom were significantly lower than relevant population norms, indicating widespread levels of poor health amongst these workers. These results suggest that globalised supply chains can provide social benefits to workers, while local food systems do not always provide desirable social outcomes. The causal mechanisms of these observations probably relate more to the social conditions of workers than directly to income.

The potential impact on farmer health of enhanced export horticultural trade between the U.K. and Uganda.

The export of vegetables from African countries to European markets presents consumers with an ethical dilemma: should they support local, but relatively well-off farmers, or poorer farmers from distant countries? This paper considers the issue of farm worker health in the U.K. and Uganda, and considers the dilemma facing U.K. consumers if Uganda achieves their aim of exporting more vegetables to the U.K. Self-reported health scores of 1,200 farm workers in the U.K. and Uganda were measured with the internationally recognised SF-36 questionnaire and compared to an international population norm. The age-corrected health status of U.K. farm workers was significantly lower than the population norm, whereas Ugandans scored significantly higher (indicating good health) for physical health and lower for mental health. If Ugandan produce enters U.K. markets, then consumers may wish to consider both the potential benefits that enhanced trade could offer Ugandan farmers compared with its impacts on U.K. workers.