Bees and moths, flies and beetles

Identifying Kenya’s vegetable pollinators

Amid Kenya’s spectacular wealth of animal life, it’s easy to overlook the insects. But they are the largest and most diverse animal group of all. The Bayer Bee Care Center is partnering with scientists and local communities in Kenya to identify important insect pollinators for vegetable farming.

Bees and moths, flies and beetles




“With this project, we aim to better understand and manage the diversity of bees and other pollinators, which may increase vegetable yields and quality for farmers in Eastern Kenya.”



Vegetable farming – a vital sector that depends on pollinators

Dr. Esther Kioko, entomologist and coordinator of the vegetable pollination project for the National Museums of Kenya (NMK).

Vegetable farming is a key contributor to Kenya’s economic growth. Much of the produce, both indigenous and non-indigenous varieties, is exported: In 2017, when this project began, the country, for instance, exported 87,240 tonnes1 of vegetables, generating 24 billion Kenyan shillings (approximately 237 million US dollars at the time).

Vegetables are commonly grown in small-scale gardens and the work is labor-intensive, with weeding, seeding, laying and harvesting all largely done by hand. These tasks create an important source of employment, especially for women, and boost household incomes in rural areas where alternative work is often hard to find.

Many vegetable farms are found in the semi-arid Ukambani2 region of eastern Kenya. Here, the focus is on subsistence rather than export, with around 96 percent of the produce consumed locally. This means farming is also a pillar of household food security and a vital source of nutrition: Many of the indigenous vegetables farmed are rich in the vitamins and iron that prevent nutrient-deficiency diseases.

Given the huge role that vegetable farming plays in people’s lives in this region and Kenya’s wider economy, it is essential to understand the inputs that contribute to good harvests. One of these is pollination, and insects play a decisive role. Yet, there is a widespread lack of knowledge about the range of insect species involved in this process.

“Many farmers don’t fully understand pollination,” explains Dr. Esther Kioko, Senior Research Scientist and Head of the Zoology Department at the National Museums of Kenya (NMK). “Some assume that their crops will just yield every year. The role of insect pollinators is a gap in their knowledge.”

To address this, the Kenyan Pollination Project was started in May 2017 to study the diversity and abundance of the insects that pollinate vegetables at two sites, Kabaa in Machakos County and Kikome in Makueni County. It was led by the NMK and Jomo Kenyatta University in Kenya, in partnership with the Bayer Bee Care Center, from where Dr. Juliana Jaramillo, then Global Scientist Bee Care at Bayer, coordinated the study. “The aim was to provide us with the data we need to raise awareness about the importance of insect pollinators,” says Esther, who is leading the project for the NMK. “With this, we can show farmers the yields they get with pollinators, and the yields they will get if they don’t conserve them.”

Dr. Esther Kioko, inspired by making a difference for smallholder women farmers and always ready to learn.

Dr. Esther Kioko, Senior Research Scientist and Head of the Zoology Department at the National Museums of Kenya, coordinates the vegetable pollination project for the NMK. In this role, she mentors MSc student researchers, participates in research work and ensures that specimens (insect pollinators) collected from the field are prepared and deposited for reference in Kenya’s National Repository. She also collates and prepares research findings for different audiences: articles in scientific journals for the research community, posters and brochures for local communities and articles about the importance of insect pollinators for the media.

How did you become interested in bees?

My first interest came from honey: Bees provide it and I love it! As I studied, I became interested in the science of insects and opted for entomology for my undergraduate course, focusing on agricultural pests. But my PhD was my first professional encounter with bees. I had a placement at ICIPE (International Centre of Insect Physiology and Ecology), measuring the value of commercial insects to people and the environment. During this project, I leaned more about insect pollinators: Their role in food and agriculture and the pollination services they provide. I became convinced that there’s something good about bees – more than just honey.

Why was the NMK interested in the vegetable pollination project?

The NMK is mandated by the government to ensure that the country’s natural heritage is understood and conserved, and this is achieved by disseminating knowledge about the natural world. The role played by insect pollinators is a gap in this knowledge and the project helps to address this.

MSc. students, Bayer representative and NMK staff during the 2017 project launch in Nairobi.

How did you choose the project sites?

Four-fifths of Kenya’s land is arid or semi-arid and we needed to reflect this, so we looked in the drier regions. We also wanted sites that were still ‘natural’ – where you have farms but also natural woodland – so we could examine the differences between these habitats and how they interplay in the lives of pollinators. Water was also needed for irrigating the vegetables in the dry season, so we chose sites along the Athi River.

The two project sites are relatively remote, meaning the communities are still ‘together’. There are women’s groups, farmers’ groups, community-based organizations (CBOs) – networks through which we could engage. By working with these groups, we were able to reach more people.

What were the main aims of the project?

Our first aim was to understand the diversity of insect pollinators in the Ukambani region and observe how they contribute to vegetable yields, in terms of quality and quantity. Next, we wanted to understand what people are doing, knowingly or unknowingly, to conserve or threaten pollinators. There are positives and negatives from current practices.

Thirdly, we wanted to build people’s capacity to understand the role of pollinators. We used community workshops to take the data back to farmers and growers; this helps them to understand. It is hard for people to protect what they don’t value, but if you can demonstrate this value in terms of yields, it helps. For example, you can show them: “This is what your cowpea pods are like if you cover the fields, as the insects cannot reach them. But this is what they look like with pollination.”

It’s not just farmers whose capacity we wanted to build, though; we also wanted to reach the research community. For example, we hope our MSc students will go on to be important players in this sector in Kenya.

What are the most interesting and most challenging aspects of your work?

Meeting different people is interesting, you can learn so much. I have worked with many researchers – from Jomo Kenyatta University of Agriculture and Technology, from Bayer – and at the community level, I meet CBO members, county agriculture officers, local government administrators, women farmers …

The biggest challenge has been working in the drylands. Water is an issue: At one site, they closed the canal that brings water from the river – but we needed water for the crops. So, we had to think: Where will we get water from? Luckily, we were assisted by a farmer who had a reservoir and the experiment could go on.

These sites are also remote. There is no mobile network, so we cannot always contact our students when they are there. The reality of working there is hard but, thankfully, we have not had any major challenges.

On-site farmer training workshop sessions were conducted in the field.

How do you think we can support small-scale farmers better, in terms of improved pollination?

At present, the project sites are pollinated by wild bees – even the honey bees are mainly from the wild. Managed beekeeping and beehives could improve crop pollination and provide an income for women farmers in particular. Another option would be planting fruit trees to support the bees, provide household food and nutrition and supply an income source. There is the opportunity to do so much more for small-scale farmers.

Which pollinators visit which plants?

MSc. student Susan Njeri Dan assessing bagged and unbagged cucumber plots at Kitise.

The project’s research team examined a number of variables related to insect pollinators and how these influenced the yields (in terms of quantity and quality) of spider plants, green peppers, cowpeas, cucumbers and squashes. The factors studied included the seasonal diversity of different pollinator species; their abundance at different times of day and night and their abundance during the blooming period. The team also investigated how the habitats surrounding vegetable gardens affected the composition and abundance of pollinators, as well as the effects of local pest management strategies.

“We found real diversity in the insect pollinators of the target vegetables.”

Dr. Esther Kioko

Over the course of the project, the team observed 77 species visiting the vegetables. These included 8 species on cowpea, 12 on cucumber, 14 on squash, 30 on spider plant and 13 species on green pepper plants (see Table 1, pg. 6). These pollinators included honey bees, non-apis bees, wasps, moths, butterflies, flies, beetles, bugs and ants.

Hummingbird moth

Carpenter bee


The data collected show that honey bees (Apis mellifera) are the most abundant pollinators in all the crops studied, except for squash, for which sap beetles were the leading species. The study identified a range of wild bee species visiting these crops, including carpenter and stingless bee species. And it is not just bees; hummingbird moth species were found to be nocturnal pollinators for African spider plants. Hoverflies were also recorded pollinating flowers of both spider plant and green peppers. “We found real diversity in the insect pollinators of the target vegetables,” confirms Esther. “Now, we want to understand their roles better and create a checklist of all the insect pollinators for indigenous African vegetables, as well as the commonlygrown, non-indigenous varieties.”

Figure 1:

Mean number of insect pollinators with time of the day in cucumber

during the short rain season from November 2017 to March 2018 (I) and the long rain season from April to July 2018 (II).

Understanding the contributions that different insect pollinators make to vegetable yields will help to guide the management of vegetable gardens. For example, the project’s in-depth analysis provided details and new insights into insect pollinator visiting patterns during the growing season. With cucumber we saw a gradual increase in the number of honey bee visits per plant, peaking between days 16 and 20 after the first flowers open. From this point on, there is a marked drop in visits. Also the numbers of honey bees (A. mellifera) and non-apis bees at different times of the day were recorded (see Figure 1).

Comparison of green pepper unbagged (l.) and bagged (r.) fresh fruit weights.

Figure 2:

Mean fresh fruit weight of green peppers (Capsicum annuum)

Experiments in the field also showed the importance of insect pollinators to crop yields. Open-pollinated plots were compared to plots in which flowers were bagged to prevent insect pollinators from accessing them. In these experiments, African spider plants and green peppers saw significantly better results across all parameters measured (pod length/weight, seed weight and number of pods) when unbagged. The mean green pepper fruit weights are shown in Figure 2. Cowpeas and cucumbers also saw heavier pods and higher numbers of fruits and seeds when the plots were open. These data provide clear evidence that insect pollinators play a leading role in improving yield quantity and quality.

Cucumbers saw heavier pods and a higher number of fruits and seeds when the plots were open to pollinators.

Small, curved, non-pollinated cucumber fruit

Pollinated (TB3r1) and non-pollinated (CB3r1) cucumber seeds

Large, straight, pollinated cucumber fruit

Laboratory analysis of seed quality

MSc. student Susan Njeri Dan bagging crops during field studies

A place to call home: protecting pollinator habitats

Information about the specific insect pollinators of different crops is useful, but to ensure that insects continue to provide this vital pollination service, it must be shared with farmers. This provides them with the knowledge they need to instigate conservation measures to protect insects. The next step for the project team, therefore, was to share the findings and build local conservation capacity.

Two MSc students, Eva Wanza Soli and Susan Njeri Dan, were trained to reach out to the communities near the project sites. Over two years, they reached 224 farmers (149 women) through training workshops for self-help and farmers’ groups. Through these, they were able to share information about the importance of insects to vegetable production and provide farmers with practical solutions to maintain a healthy, pollinator-friendly environment. These efforts had a significant impact (see Table 2).

´In Eastern Kenya, smallholder women farmers, who play a critical role in food production for their families, will be able to evaluate their farming practices and improve the availability of forage for pollinators, necessary for improved crop quality and quantity, thanks to this project.´

Table 2:

Farmers knowledge and awareness of insect pollinators

Status on key issues at project start and status change after project implementation

Knowledge and awareness of insect pollinatorsFarm management practicesRole of natural habitats in sustaining insect pollinators

Before project outreach activities, farmers:

Initial status

// thought mainly of honey bees as insect pollinators

// disregarded insect pollinators’ inputs to vegetable production

// were misinformed that most insects found on vegetable crops are pests/disease vectors

// were burning areas to ‘clean’ farms, thus destroying the breeding, foraging and nesting sites for insect pollinators

// were indiscriminately using chemical pesticides that killed insect pollinators

// were leaving farms exposed to soil erosion

// cut down trees to support their livelihoods

// overgrazed land, reducing food sources for insects and destroying their nesting sites

Outreach activities // The project:

// provided evidence on the importance of insect pollinators in vegetable production, such as posters to share information on yield differences between bagged and unbagged plots

// offered practical on-farm demonstrations

// provided knowledge through training workshops and discussions

// discussed Integrated pest and pollinator management (IPPM) strategies

// provided data about how surrounding natural habitats can support insect pollinators

After project outreach activities, farmers:

Status after project

// recognize insect pollinators other than honey bees

// understand the effect of insect pollinators on yield quality and quantity

// are aware of the use of pheromone traps for pests, like fruit flies

// have knowledge on cultural practices that can enhance their vegetable crops

// are creating terraces to tackle soil erosion using conservation agriculture practices, such as leaving hedgerows in place and planting grasses

// are trained in the use of environmentally-friendly pest control products; they now see more pollinators on their farms and have higher yields, improving nutrition and food security

// are engaged in agroforestry using zero-grazing practices

// now avoid slash-and-burn methods to clear forests for farmland, retaining intact woodland patches

“Farmers now have a better understanding of which pollinators visit their crops and appreciate their role in improving yields and quality,” says Susan Dan. “We are seeing more positive attitudes towards pollinators and the application of appropriate conservation measures.”

Diversified farm system view in Machakos County, Kenya.

Importantly, many more farmers now understand that food security is dependent on how the environment is managed. As a result, they are shifting towards integrated pest and pollinator management (IPPM), an approach that must be applied to both vegetable farms and the surrounding habitats as these are an essential source of food for pollinators when a crop is not in flower. These habitats, mostly non-vegetable farms and forest, contain a rich diversity of life: Surveys outside the experiment plots identified 189 different insect species, while a survey at Kikome revealed 182 different plant species. “Just like humans, insects need a place to call home,” says Susan. “Creating and managing the habitats around farms, where insects can nest, breed and feed, is a useful pollinator-friendly measure.”

Conservation measures which are proving popular with farmers include planting a diversity of native flowers in and around the vegetable gardens. “Different insect pollinators are attracted to flowers of varying height, shape and color,” explains Susan. “Gardens with this variety attract diverse insect pollinators.” Diversity of plant species also helps to maximize the blooming period, as various pollinator-friendly species bloom at different times throughout the year.

In addition, the project provided useful guidance regarding the best approaches for engaging with farmers. “Exhibitions that explain the positive outputs gained from insect pollinators – namely bigger, more marketable seeds and fruits – are one way,” says Susan. “Reading materials that explain the principles of managing and conserving insect pollinators are also useful for farmers – if they are in local languages.”

Even though the project ran for just two years, the results speak for themselves in terms of the species identified and the farmers reached. And the people living in and around Kabaa and Kitise can look forward to more varied and nutritious diets, thanks to the vegetable farmers – and thanks to the insects that pollinate their crops.

Carpenter bee (Xylocopa flavorufa)

foraging on a legume flower in a mixed farming system in Machakos County.

Honey bees:

The most recognized insect pollinator.

A typical smallholder mixed-crop farm in Kabaa, Machakos, is adjacent to natural woodland which serves as a reservoir for insect pollinators.

A brighter outlook for Kenya’s smallholder farmers

Scientists, farmers and beekeepers are striving to discover, use and share new knowledge about bees and other insect pollinators. Knowing more about the many different species that visit their crops will help farmers make the right choices about how to manage their farms, and also underpin efforts to ensure that pollinators are protected and conserved. Above all, the project has deepened the understanding and appreciation of these pollinators – for their benefit, and ours.

By Esther Kioko

Bees and people – an ancient Swahili connection

Swahili language is rich with proverbs and riddles; they are a way to pass on messages. And many are linked to bees.

Fuata nyuki ule asali:

“Follow the bees and you will eat honey.”

Most people associate bees with honey and people value honey in Kenya. In traditional marriage ceremonies, a man must bring honey or he will not have a wife.

I would like to dig deeper, to understand the cultural relationships between people and bees in Kenya. Cultural beliefs are another way to engage people with pollinators. And yet often these proverbs focus on the negatives.

For example:

Bila kumshinda nyuki hupati asali:

“You must confront and defeat the bees to get the honey.”

Children are often told this – it can be understood that, if you want to succeed, be ready to deal with challenges. But this idea of ‘defeating’ the bee needs to change.

Some sayings are more sympathetic to bees, though, and appreciate what they give us:

Fadhili ya nyuki ni moto:

“Despite its hard work, the reward for the honey bee is fire.”

This phrase acknowledges that bees work hard, yet all they get in return is fire and smoke (people harvest honey by smoking out bees*). I would like to understand how people came up with this saying, and find new ways to give bees the rewards they deserve – food and a better environment. Bees do not just give us honey: They contribute to much of the food we eat. Can we give them better rewards?

* Honey was in some instances harvested from hollow tree trunks or crevices by using twigs with fire as a means of chasing off the honey bees to access the honey. In many of the cases, the bees were oversmoked and often, unfortunately, burnt to death.

Stingless bees: alternative pollinators for African crops

Dr. Nkoba Kiatoko, postdoctoral fellow at ICIPE, leading the multi-stakeholder stingless bee project.

Elsewhere in Kenya, scientists are concentrating their efforts on increasing our knowledge about one particular group of pollinators: stingless bees (Meliponini). The potential of this group is exciting because most species possess traits similar to honey bees, which makes them suitable for rearing by farmers. For example, they produce honey; they live in colonies, with queens, workers and drones; they recruit foragers and they show floral constancy (prefer large quantities of flowers of the same species).

Perhaps most significantly, being stingless means they are a ‘friendly’ species. “Many farmers have lost goats or cattle to bee stings and so are not always keen to keep them,” says Dr. Nkoba Kiatoko, a postdoctoral fellow at ICIPE (International Centre of Insect Physiology and Ecology) who leads this project to improve the understanding and knowledge concerning pollination efficiency and honey production. “Stingless bees can be a better option for the many farmers who combine agriculture with livestock-keeping.”

The high quality of stingless bees’ honey is another attraction, as this is important in many African cultures for medicine, food and rituals. “Their honey can be worth ten times that of honey bees,” confirms Kiatoko. “For example, when they forage on medicinally-important plants, these qualities are transferred to the honey – adding to its value.”

Run by the African Reference Laboratory for Bee Health at ICIPE, with the Bayer Bee Care Center collaborating in many of its research strands, the project will run until June 2022. A future update will provide further insights into this exciting project.

“Stingless bees can be a better option for the many farmers who combine agriculture with livestock-keeping.”

Dr. Nkoba Kiatoko

A project partner in Ethiopia shows trainees study colonies of stingless bees (Meliponini) so they can learn how to manage them (above and below).

1 According to the Fresh Produce Consortium of Kenya. See: and search “Kenya vegetable exports 2017”

2 The name means ‘land of the Kamba’ or Akamba people, and it comprises Makueni, Kitui and Machakos counties.

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Bees and moths, flies and beetles Identifying Kenya’s vegetable pollinators
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