When the bees are gone
above The long-term viability of hand pollination is being challenged by rising labour costs and declining fruit yields right Heavy pesticide use on fruit trees in the area has caused a severe decline in wild bee populations
Doing the work of bees
In China’s mountainous Maoxian region in Sichuan Province, there are almost 6,500 hectares of pear and apple orchards. Every year, villagers descend on the farmlands to begin the monumental task of pollinating every single fruit blossom – by hand.
Apple production in the Maoxian Valley began in 1946 with 400 trees. By the 1980s, the region had over 200,000 trees, with apples being the county’s leading crop yield. By the late 1990s, Maoxian was producing over 30,000 tonnes a year to the value of USD6.4 million. With this burgeoning commercial success came the increased use of pesticides, overtaking the more traditional organic fertilisation methods. The 1990s saw overall apple productivity decline by half, attributed to the mysterious disappearance of bees.
The pollination of apples in Maoxian has to be completed within five days in order for the trees to bear fruit. When the trees blossom, the villagers go out en masse, armed with small paint brushes. They use homemade pollination sticks made from chicken feathers and cigarette filters and dip them into a pot full of purchased pollen, and then rub the end of the stick to the pistils of the tree flowers. Children clamber up to pollinate the higher parts of the tree. One person can pollinate between five to 10 trees in a day.
In a village in Nanxin, farmers have been using hand-pollination – also called “mechanical pollination” – for the past two decades to ensure their trees yield fruit. However, the long-term viability of hand pollination is being challenged by rising labour costs and continuously declining fruit yields.
Bioprofit conducted an investigation into the declining bee issue in the Sichuan Valley in 2001. Unable to identify one exact cause of their disappearance, scientists put it down to several factors. Pesticide was one significant influence, as was over-farming, resulting in the destruction of the bees’ natural habitat. They also found that commercial bees had been introduced to the area to counteract the deficit in the numbers of indigenous bees, but, according to Bioprofit, the overuse of pesticides subsequently killed them all.
Surely, then, there should be some form of pesticide regulation in place? As it turns out, there is. China’s Ministry of Agriculture has set out standards for use, but implementing them is another story. While there are natural pesticides available, they cost far more than the chemical equivalents, and so, the budget-conscious farmer will go for the cheaper, albeit more environmentally harmful, option.
The 1990s saw overall apple productivity decline by half, attributed to the mysterious disappearance of bees
The planting of polliniser trees, such as the crabapple tree – which are introduced to the orchard to provide pollen for the bees to fertilise with – may have been another contributing factor. The Maoxin farmers were planting less than 10 percent polliniser trees, thinking that it would not be commercially viable to have more.
Climate change is the other major contributor to the problem. The Maoxin farmers reported unusual changes in weather patterns, such as rain and hailstorms uncharacteristic for the blossoming season. Rapid temperature changes were reported, too. And then there is the huge pollution problem in China.
In 2011, Bioprofit returned to the region. They found that many farmers had substituted their apple plantations with other crop varieties that didn’t require bees for pollination. The once lucrative Maowen apple industry operates at a fraction of its previous productivity.
The bigger picture
For most of us, the buzzing of bees amongst the flowers is a quintessential part of a summer atmosphere, the sound of lazy picnics in a sun-drenched meadow or of relaxing afternoons sipping cold drinks lounging in a deckchair in the garden. We should not take this sound for granted, for there are now places in the world, such as the Sichuan Valley, where this hum can no longer be heard – where the bees are gone.
Bees are perhaps the most important insects on the planet, for they pollinate our crops; about three quarters of all the types of crops we grow to eat need pollination by insects to give a full crop yield. Without bees, we would not have raspberries, runner beans, courgettes, tomatoes, chilli peppers or coffee, to name just a few. About a third of all the food we consume by weight depends upon pollinators. Without bees, our diet would consist largely of produce from windpollinated plants: rice, maize, wheat and barley. In short, without bees our diets would be more than a little dull.
It is a common misconception that more or less all pollination is done by honeybees, the familiar bees kept by beekeepers from which we get honey. This is, however, a very long way from the truth. There are some 20,000 known species of bee in the world, plus other insects such as hoverflies, butterflies and beetles that also pollinate.
About three quarters of all the types of crops we grow to eat need pollination by insects
Different insects tend to visit different flowers, and are better suited to pollinating some than others. Tomatoes and blueberries, for example, are best pollinated by bumblebees, while mason bees are excellent at pollinating apples. We have tiny flies to thank for giving us chocolate, for it is they that pollinate the cacao tree.
Disturbingly, however, many of these pollinators are in decline. Some species, such as Franklin’s bumblebee ( Bombus franklini), once found in the western US, are now extinct. Others cling on to existence, but are far less common than they once were. Populations of insects such as the Monarch butterfly ( Danaus plexipus) in North America, or the great yellow bumblebee ( Bombus distinguendus) in Europe have dropped by about 90 percent.
This is a matter of the utmost concern, for we cannot feed a growing global human population without our insect allies.
What has happened to our pollinators? The answer is complex, and there is no one villain to blame; humans have created a hive of problems for pollinators.
The biggest driver of pollinator declines is a lack of wild flowers. Farming has changed enormously in the last 100 years, from an age of low-intensity farming of small fields to an era of vast crop monocultures, fields that stretch to the horizon, with not a weed or wildflower to be seen. Some crops, such as oilseed rape or sunflowers, provide food for bees, but only for a week or two, and for the rest of the year there is nothing for them to eat. Maintaining these fields free from weeds is greatly aided by modern herbicides such as glyphosate, which allow farmers to grow perfect monocultures of crops.
To make matters worse, humans have inadvertently spread bee diseases and parasites around the globe with domestic honeybees, and also with commercially-reared bumblebees that are used for tomato pollination. For example, the careless movement of bees has spread the Varroa mite – a tiny bloodsucking parasite which attacks honeybees – to almost every country in the world. Similarly, wild Japanese bumblebees now have to cope with attacks of European tracheal mites, which infest their breathing airways.
To add to these problems, the modern world is full of insecticides that are directly toxic to bees. Farmers spray their crops with organophosphates, pyrethroids and neonicotinoids, all chemicals intended to kill pests, but which inevitably cause collateral damage. The neonicotinoids are particularly insidious, for they are persistent and systemic, getting into plant tissues and then into their nectar and pollen. In gardens and towns, a similar barrage of chemicals is used to kill garden pests, mosquitoes, flies, ants, or fleas on domestic animals.