Research Finds Protecting Pollinators is Critical For Food Security in Africa

Agrilinks Team

Nov 06, 2020

This post is written by Sunday Ekesi, Michael Lattorff, Thomas Dubois, International Centre of Insect Physiology and Ecology (ICIPE).

Background

Pollination is crucial for food production, human livelihoods, and the preservation of biodiversity in natural ecosystems. Global crop production is highly dependent on pollinators. Approximately 75% of all crop plants are dependent on animal-mediated pollination and a recent analysis estimated the annual market value of pollinator services at US$235-577 billion. Thus, pollinators and the pollination services they provide serve a crucial function in food security. In many developing countries, agricultural production has become increasingly dependent on pollination services, as the relative number of pollination-dependent crops has increased three times compared to developed countries over the past 50 years. Pollination of crop plants by insects also contributes directly to human nutrition by increasing the availability of critical micronutrients. Animal-pollinated crops contain the majority of the available dietary lipid, vitamin A, C, and E, which are critical for the physical and intellectual development of children, as well as of key importance to other vulnerable groups including pregnant women, populations in disease risk regions (e.g. malaria endemic regions), and immuno-compromised individuals (due to malnutrition or pre-existing conditions). Beyond supporting crop production and human health through a diversified diet, pollinators are also a source of several commercial products (e.g., honey, wax, bee venom, royal jelly and resins) important for cosmetics, medicine, and cultural identity. Yet, despite their importance, pollinators are under increasing pressure and populations are declining worldwide.

Pollination R4D to improve food security: Examples from the International Centre of Insect Physiology & Ecology (ICIPE)

Assessing pollinator diversity

Globally, declines in insect pollinator populations (due to diverse factors including unsustainable agricultural practices, habitat destruction, and climate change) are threatening crop production amidst the growing demand for food driven by human population growth. To conserve and augment the population of pollinators for horticultural crops, we first need a basic understanding of their diversity. In this regard, we have undertaken surveys on avocado along the altitudinal gradient of the Eastern Afromontane region of Taita Hills, Kenya. Diverse pollinators belonging to 28 species in 14 families were observed visiting avocado. Overall, the proportion of honeybee (Apis mellifera) visits were the highest. In Murang’a, Kenya, a richer assembly of flower visitors was observed — including 73 species in 29 families. The most abundant families were Apidae, Calliphoridae, Rhiniidae, and Syrphidae. Honeybees comprised 95.8% of Apidae. Other bee species included Braunsapis sp., Ceratina (Simioceratina) sp. (both Apidae), and Nomia sp., Lasioglossum sp., Pseudapis sp. (both Halictidae). On macadamia, stingless bee species from the genus Hypotrigona and Liotrigona have also been identified as efficient pollinators to enhance pollination and increase the productivity of the crop.

Understanding pollinator deficits and exploring opportunities to utilize pollinators to increase crop yields

Intensification of agriculture is leading to losses of wild pollinator species and hence of pollination services required to increase crop yields. As a result of the threats facing honeybees and other pollinators, ICIPE has been developing tools to utilize alternative managed pollinators (e.g., honeybees, stingless bees, and carpenter bees). In one of the major avocado growing areas of Kenya (Murang’a county), we analyzed the pollination deficit in avocado. This is the decrease in crop yield due to lack of sufficient pollination services. We found a 27% loss of fruits due to suboptimal pollination. However, supplementation of smallholder avocado farms with two honeybee colonies was sufficient to reverse this pollination deficit, increasing avocado yield by 180% and income by US$168 per farmer per season.

The domestication of stingless bees as alternative pollinators is a major component of activity at ICIPE. Through this activity, it has been possible to domesticate 14 species from East, West, and Central Africa; among which 6 have been widely evaluated and promoted with respect to their pollination efficiency. We are currently implementing activities for the use of stingless bee-targeted pollination on specific crops in open fields. In Kakamega, Kenya, research activities implemented jointly with smallholder farmers on pollination showed that stingless bee species, such as Hypotrigona gribodoi, are more efficient in improving green pepper fruit and seed quality in open fields compared to other wild pollinators. We also determined that the stingless bee species Meliponula bocandei and M. ferruginea are more efficient than honeybees in the pollination of sweet melon and cucumber. Recently, we also demonstrated that flower odor learning in stingless bees is species-specific, and that specific vibrational sounds are used to recruit foragers to crop plants. In an ongoing Mastercard Foundation-funded projects (Young Entrepreneurs in Silk and Honey [YESH] and More Young Entrepreneurs in Silk and Honey [MoYESH]) aimed at expanding commercial beekeeping, entrepreneurial and decent employment opportunities for >100,000 youth in Ethiopia, pollination of horticultural crops, especially vegetables using honeybees and stingless bees, along developed watersheds and rehabilitating landscapes, is being promoted as a complementary income generating opportunity while also providing diverse bee forages. Already, a cohort of 16,926 partner youth (59% female) have been recruited at project action sites and organized into 1,263 business enterprises designed to enhance agribusiness and income generation opportunities for rural youth and women in the country. Model beekeeping sites will be used to demonstrate managed beekeeping as an integral component of sustainable ecological farming that promotes healthy food, healthy farming, and a healthy environment.

Bee health R4D in support of pollination services

ICIPE has established the African Reference Laboratory for Bee Health (ARLBH) at its headquarters in Nairobi, Kenya, with four satellite stations in Liberia, Burkina Faso, Cameroon, and Ethiopia, as well as a diagnostic laboratory in Madagascar. This is the first of its kind in Africa. The ARLBH was accredited as a Collaborating Centre for Bee Health in Africa by the World Organization for Animal Health (OIE). Activities in the facility include assessment of environmental stressors like pesticides and habitat deterioration responsible for bee declines, development and establishment of diagnostic tools for pesticide residue analysis, surveillance for bee diseases, and establishing measures to protect them.

Improving habitat protection and restoration

Large-scale land transformation puts insect pollinators at risk, as land use change often results in degraded or fragmented habitats, that can no longer support pollinators due to the lack of nesting or foraging habitats. We have demonstrated that habitat deterioration, which includes natural forest loss, reforestation and afforestation with exotic tree species, negatively impacts species richness and diversity of stingless bees in sub-Saharan Africa. In fact, most stingless bee species are susceptible to habitat degradation since they tend to have very specific nesting requirements and only few species accept a broad range of natural and artificial substrates.

Strengthening pest and disease surveillance and management

Selected pollinator pests have been identified as being a particular concern to pollinator populations, including the wax moth (Galleria mellonella) and large and small hive beetles (Oplostomus haroldi and Aethina tumida) respectively. An initial survey provided high quality data that have been used, in combination with modeling approaches, to predict regions of high pest risk. The chemical and behavioral ecology of these pests has also been studied in detail, with the aim of developing control measures based on using chemical agents as attractants or repellents in traps. In Kenya, small hive beetles have also been identified as a major pest affecting stingless bee Meliponula species. Additionally, we have established that the Black Queen Cell virus that attacks honeybees can also be transmitted to stingless bees. Finally, we have also determined the resistance and tolerance mechanisms of African honeybees to the ectoparasitic mite Varroa destructor, potentially the most severe bee-pest. A plant-based bio-pesticide has been developed that is effective against the Varroa mite and has a repellent effect on the small hive beetle.

Decreasing the risk of pesticide use in crops and foraging plants, and adopting pollinator-friendly agricultural practices

While pesticide residue levels currently remain below international standard norms (e.g. EU standards), ICIPE and partners have observed an increase in pesticide residues in beehive products, which implies that pollinators are picking up pesticides applied to crops that could in turn affect their health. Pesticide use is increasing in sub-Saharan Africa, and ICIPE has piloted the use of ‘integrated pest and pollinator management (IPPM)’ to ensure that crop protection is harmonized with pollination services on pollinator-dependent crops such as avocado and cucurbits. In Kilimanjaro, Tanzania, and Murang’a, Kenya, we are implementing best-bet integrated pest management (IPM) package based on  fungal bio-pesticides, attract-and-kill products, and protein baits that enhance pollinator diversity while reducing pest populations (such as the oriental fruit fly — Bactrocera dorsalis — and the false codling moth — Thaumatotibia leucotreta) on avocado across landscapes. So far, more than 1,400 farmers in Murang’a have been trained on the use of IPPM, and many have adopted the practice to combat avocado pests without negatively impacting pollinators.

Understanding the bee microbiome to improve pollination services

Honeybees and stingless bees harbor diverse gut microbiota, which are critical to a variety of physiological processes — including digestion, detoxification, immune responses, and protection against pests and diseases. Surprisingly, whereas beekeeping has been widely promoted as a tool to mitigate poverty in tropical and subtropical regions of the world, no comprehensive studies of honeybee gut microbiota have been done in sub Saharan Africa where pollen and nectar resources are present year-round. Moreover, Africa hosts a highly significant diversity of bee species that might be associated with significant and uncharacterized gut microbe diversity selected for by different evolutionary pressures. ICIPE’s goal is to increase pollinator fitness and thus the pollination services they provide by investigating gut microbiota-host interactions. With the use of comparative genomics and microbiology tools, we are characterizing the nature of specific beneficial interactions. Results indicate that microbial abundance varies with geographical locations. We are currently investigating the parameters affecting this abundance as well as uncovering novel members of the microbiome that we found to be specific to Africa, in an effort to enhance pollinator health and pollination services.

Modeling climate change impact on pollinators

Climate shocks and land use change increasingly affect the life cycle as well as spatial and temporal distribution patterns of pollinators (e.g., honeybee, stingless bees), their pests, and the flowering plants upon which they depend for food and shelter. These habitat changes and climatic shifts have a trickle-down effect on pollination efficiency and thus food security. We are using replicable analytical methods and novel procedures for assessing the impact of climate and landscape change on the current and future distribution and abundance of honeybees, stingless bees, their pests, and flowering plants. Using long-term climate data with time-series satellite data variables overlaid on actual land surface properties and dynamics (i.e. changes in vegetation chlorophyll activity over time), we have developed accurate and realistic pest risk maps to guide interventions with regard to managing the pests of these pollinators using bio-pesticides without harming bees. Within the landscape mapping context, we have developed a sophisticated algorithm to map floral responses from spectral imagery. This is helping to understand the role of landscape fragmentation and the distribution, abundance, and temporal availability of flowering plants, pollinators, and pollination services. The knowledge on the value of natural habitats for bees within agro-ecological landscapes (using flowering and fragmentation maps) should be an incentive for the protection of these habitats.

Strengthening the capacity of farmers and national systems

Capacity building of farmers and national agricultural extension systems has been integral to building awareness of the important role pollinators play in improving food security. Training activities range from minimizing pesticide use, adopting pollinator-friendly agricultural practices, incentive to communities to support conservation of pollinators, and training of graduate students (PhD and MSc). Over 17,793 farmers and 816 extensionists have been trained across 21 Francophone and 23 Anglophone speaking countries across Africa. A total of 32 graduate students (PhD and MSc) have been trained across different countries (Kenya, Burkina Faso, Belgium, Uganda, Cameroon, Ethiopia, D.R. Congo, South Sudan, Nigeria, Ghana, Tanzania, Madagascar).