Stingless Bees - can these pollinators save our crops?
Tetragonula, Melipona, and other stingless bees are the modern descendants of hunting wasps who gave up hunting and became vegetarians living on nectar and pollen. The oldest known bee fossil evidence is the 100 million year old Patagonian example of Halictidae underground nests, linking bees to their wasp ancestors. Traditional ancestors to Apis mellifera (the Western Honeybee that most people are familiar with) may have been around this early, but so far the fossil evidence only begins 25 million years ago in Germany.
Pollinators and their Benefits
Pollinators are absolutely vital to our ecosystem because, through their activities, many diverse aspects are supported. It is not only bees, of course, but they do shoulder a lot of that burden, and people recognise them as the main pollinators for most of our crops.
Though many plants can self-pollinate when there are no pollinators around, this can lead to endogamic depression (like marrying your cousin) resulting in less durable progeny and lowered nutritional value. Stingless bee can solve this problem by making sure plants are getting pollen from multiple plants. Melipona and Trigona (Tetragonula) make crops healthier and more productive by providing this diversity.
Interestingly, some crops, like tomatoes, are best fertilised by "buzz" pollinators like bumblebees that shake the pollen loose. Few bees behave this way, but the Melipona stingless bees most certainly do. Better pollination equals better crops!
In the U.S., the fascination with plant-based almond milk has led to repeated doubling of the almond farming industry. Bees are brought in from all over the country to pollinate the Californian crop, supplying up to 80%of the annual income for pollinating beekeepers in that country. Honey comes in at a surprising second place in the money-picture.
The problem is that monoculture is not good for honeybees nutritionally. About nine times the human population of our planet, around 50-60 billion translocated honeybees, die each year during the almond operation in California. Worse yet, they bring infections and parasites back to their home hives which can cause colony collapse.
Stingless bees produce as little as 1.7% the amount of honey compared to Western honeybees. A. mellifera can produce 60 kilograms per hive annually compared to one kilogram for the smaller hives of stingless bees. Some larger stingless hives (still comparatively small) can produce up to three litres of honey per year. However, since honey production is not the main purpose here, substituting or supplementing with stingless bees could see a significant decrease in honeybee mortality.
Almond farms now cover more than 501,000 hectares (1,240,000 acres) as the industry seeks to quench the thirst for almond milk and other products. Depending on locale, 35% of our food relies on pollinators – and let's not forget the honey, which is nutritious, antibacterial, full of minerals, and delicious.
In a broad parallel, hummingbirds are pollinators, too, and are so extremely specialised that dozens of varieties can coexist in a small, yet non-competitive, space. Each type has its own preferred (or essential) thin-necked, long, tubular flowers that others cannot use.
Similarly, bats are important pollinators. They feed on pollen, nectar, and insects hiding inside flowers. Consequently bats pollinate over 300 different kinds of fruits.
We rely on all pollinators to fertilise many of our crops, not just for food, but for medicines, flowers, trees, edible oils, fibres, and much more. It does not end with humans, however, since as a direct consequence of their activity, there are whole habitats reliant on that biodiversity to spawn places in where animals can live, and to provide food which they can eat.
Virtually all species are interdependent because they interact in the same ecosystem. It is the relationship to the plants themselves that allows the coexistence of types. Both Tetragonula (Trigona) and Melipona bees are known to visit the flowers of around 90 crop species, and are particularly useful for tomatoes, cucumber, eggplants, cherry, coffee, canola, guava, passion fruit, the oil palm, and more. Typically anything found or growable in tropical or subtropical climes benefit in some way from their presence.
Threats to Pollinators
Bees even have a collection of foes that target them. The Israeli Acute Paralysis virus is a significant threat to bees, often connected to colony losses. As well, there is the Varroa destructor mite that spreads viruses to the colonies, killing them off, too.
Due to a variety of reasons, 17% of all pollinators are currently threatened by extinction, and 40% more are on the verge. It can be a self-perpetuating loop as fewer pollinators can maintain fewer habitats, and more species wane due to habitat loss.
Habitat loss is a massive threat to our biodiversity. Some countries, such as Brazil, in a bid to develop economically, have clear cut or burned down swaths of rainforest to raise (currently) 200 million head of cattle. Eradicating 45 million hectares of rainforest (just in Brazil) for ranching means there is less space for pollinators and other species. This amplifies the effect further away from the pastures themselves.
Fragmentation of the pollinator nesting sites is problematic, but it is worsened for migratory pollinators. The North American Monarch butterfly travels 5,000 kilometres each way every year. When stopover sites are too widely spread, many individuals do not survive the trip.
We also often see pesticides being used indiscriminately, too, because people are not trained properly. Applied on a schedule instead of "as needed" ends up costing more money, kills pollinators indiscriminately, and harms the environment. Learning to use the right kind of pesticides, smallest amount, and only where needed, would be a big step in the right direction.
Lastly pollution is intrinsically harmful to our pollinators. We have the capability to control, collect, repurpose, or reprocess our leftovers. Failure to do so does not only threaten them but all other life on the planet. It also threatens billions of dollars, pounds, or euros in productivity, and millions of livelihoods, according to a 2016 report by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services.
Are they dangerous?
Most bees don't sting. Only 10% of bees are social; the remainder are solitary, live in underground tunnels or in tree trunks rather than hives, and are non-honey-producing. Less than 5% of all bees produce honey, instead relying on nectar and pollen loafs that provide their young with nutrition until they mature. They have mandibles and can bite; some can even produce a burning substance (compare: Fire Ants, a relative) for defence.
Honeybees sting—or so many believe—and that is true for one variety that we cultivate, A. mellifera, aka the Western or Italian Honeybee. In the wild, they do need to defend against honey-thieves because these bees are producing truly massive quantities of a valuable and desirable resource to get them through the winter and feed their young when there is no other food available. Even so, unless they are Africanised, they are generally docile away from their hives.
Stingless bees (Melipona and Tetragonula), on the other hand do not sting. Stingers are modified egg-laying tools, and thus are present only on females, but on stingless worker-bees they are vestigial and mostly non-functional. Their defence in the wild is in their nest placement, and being essentially inaccessible.
Are they invasive?
Beyond that there is the issue of whether they are an "invasive species". With A. mellifera, in just one instance, despite a massive, concerted, decades-long effort by German beekeepers, they could not replace indigenous species with superior honeybees—the effort failed. The native populations continued to thrive.
Do stingless bees like Melipona and Tetragonula supplant native species? Evidence shows they do not, because they are too small to wander far from their hives. When used outside of their normal tropical or subtropical environment they are incapable of adapting to the cold weather.
Do bees cause harm to human interests?
On the contrary, honeybees of all varieties are a great benefit to human interests, forming the basis of an industry built on moving them from location to location to pollinate seasonal crops.
Do bees destroy biodiversity?
Evidence indicates that their presence enhances biodiversity, allowing more plants to thrive, increasing genetic transfer, and particularly in fragmented ecosystems. An isolated patch of vegetation still receives external pollen, where this might not otherwise be possible, allowing it to spread, enhancing its survival chances.
Diversity of Bees Aids Crop Pollenation
Using honeybees to pollinate in retail hot houses, glasshouses, and greenhouses can be problematic if they are of the A. mellifera variety. Although the Western Honeybee is generally docile, there are too many opportunities for stinging behaviour problems when interacting with humans. Both Tetragonula and Melipona bees are safe enough to have in a public retail greenhouse, and their size does not inspire fear in most people. They are often mistaken for houseflies by the uninitiated.
Stingless bees are much easier to manage. Since they are of small to medium size, frequently less than 4 mm long, they tend to stay within a maximum of 500 metres of their hive. Several small hives in each large greenhouse can maintain the whole facility with no problem.
Safe for Native Species
Japan (for example) uses the Tetragonula stingless bees' susceptibility to cold as a form of control. They can only thrive in tropical (or greenhouse) environments, and cannot survive a cold winter. This allows Japanese growers to maximise food production without threatening their indigenous bee populations. There are far too few apiarists (beekeepers) in Japan to manage the whole country, so these small, low-maintenance bees are perfect for smaller farming operations.
Generally, when used in temperate climates, Tetragonula stingless bees cannot invade outside the closed environment. They do not build temperature controlled nests because, unlike their Apis honeybee cousins, they lack the ability to use water to condition the air and regulate temperature within their hives.
More importantly, stingless bees are easy to handle for those with little experience. Instructions for maintaining temperature ranges, humidity, and light levels can come with each colony, species-tuned to the predominant crop and conditions. There are many different kinds of stingless bees that can fit in your desired environment.
In fact, of the 20,000 species, there are over a 130 varieties of the genusTetragonula, and over 50 varieties ofMeliponabees in the world.Like other bees, they serve a vital purpose in the plant world.Without them, many flowers that are too small for conventional honeybees to service would go ignored and the plants would die off.
Essential for Certain Crops
Stingless bees are noted as essential in over 18 commercial crops, and contribute in about 60 more. For example, in Australia, they have been shown to be the best pollinators of crops such as lychees, mangos, watermelons, coconuts, and macadamias. They also benefit strawberries, citrus, avocados, potatoes, squash, and tomatoes.
Melipona are particularly useful to replace or supplement buzz-pollinators like the bumble bee. Honeybees simply cannot perform buzz-pollination. Consider the crops of potatoes, assorted peppers, blueberries, and tomatoes. These plants do not produce nectar to attract insects. Instead they have hidden pollen bearing stamens with poricidal anthers to protect their pollen from non-pollinating visitors. These hold on to the pollen tightly.
By grasping the flower quite firmly and vibrating their wing muscles, the stingless Melipona can cause the release of a lot of pollen. This benefits the plant with increased fertilisation and biological gene sharing through a bee that will definitely visit other flowers of its species and transfer the pollen. The plant, in turn, rewards the bee, with increased food.
Both Melipona and Tetragonula stingless bees are good for field pollination when warm temperatures prevail for part or all of the year. If there is a cold winter, hives can be moved indoors to greenhouses so they can maintain their year-round pollination activities. When Apis honeybees are quiescent during the winter, Trigona and Melipona are still hard at work, ceaselessly pollinating year-round to enhance commercial crop production.
Alternatively, they can be transported to other areas where seasonal warm temperatures prevail. At any given time a hive can pollinate a one kilometre circle around its location since that is about the limit to which they wander. These smaller hives are fine outdoors, and any "escapees" perish in winter, if they leave the hive attempting to live outdoors.
Indoor Urban Agriculture on the Rise
Melipona and Tetragonula stingless bees are almost ideal for indoor urban agriculture. Companies on the rise, like the United States' Gotham Greens, Bowery Farming, and even Jeff Bezos' Plenty, are massive enclosed facilities designed for local, low-impact food production close to, or within, urban centres.
They're not alone—there are 25 large-scale operations in Israel, Dubai, the Netherlands, and several other countries, too. The year-round environmentally controlled operations will need year-round pollinators like stingless bees to keep them in constant production and feed a hungry world.
Melipona can handle just about anything you can grow indoors including peppers, tomatoes, potatoes, strawberries, macadamia, mango, squash, avocados, or virtually anything with a flower. In fact, indoor horticulture is predicted to be a US$700 billion industry by 2030, five times greater than current levels.
Melipona and Tetragonula stingless bees can fill a significant gap in areas where ordinary pollinators are in short supply. More importantly, these hives do not hibernate—they run all year long—never ceasing, and grow year over year, allowing for splitting, and making them self-sustaining and self-replacing.
Even for self-pollinating crops, research clearly shows that productivity is greatly enhanced when plants are pollinated by bees rather than on their own. Genetic diversity increases; plants get stronger and hardier; crop output increases by several tens of percentage points. It is simply better to let natural pollinators do the job they evolved to do.
Ultimately it is up to you to pay attention to all the buzz and look into better field crop or indoor crop management. You can get more for less, simply by learning to manage your own pollinators. Stingless bees pay for themselves—now let them pay for you, too!