As the first shoots and blooms appear, Clare Bryden welcomes the returning buzz of bees, and takes a year-round look at the complex threats to these and other pollinators so necessary to the interconnected web of creation.
Spring is on its way. The sun is returning after another northern hemisphere winter. The days are getting longer, temperatures are rising erratically, and it is time for beekeepers to discover whether their hives have survived the winter or succumbed to weather or disease.
Honeybees have one overarching job in the winter: to take care of their queen. So as the weather cools, the worker bees form a winter cluster around her with their bodies. The cluster is in constant flux. The bees flutter their wings and shiver to maintain its core temperature, and continually rotate in from the outside so no individual gets too cold. When the weather becomes colder, the cluster becomes tighter. As winter progresses, it moves through the hive to reach the stored honey that the bees need for energy.
WINTER TO SPRING
Enough food should be left in the hive to build its strength in time for the main nectar flow. If not, beekeepers may need to feed the colony to avoid starvation. Honeybees are susceptible to disease and other problems all year round. Some die-off is expected during winter. But extended cold weather periods increase the risk of dysentery and Nosema disease as bees are unable to leave the hive to eliminate faecal waste. Then as brood laying begins again in early spring, wet weather brings the hazard of chalkbrood.
As temperatures rise, bees start to venture out again to feed on pollen and nectar. Pussy willow is among the first plants to blossom, sticky buds exploding into soft catkins tipped with bright yellow pollen grains, and pulsing with the hum of foragers.
The well-ordered activity of the hive is in full swing now. There are resonances of the Body of Christ, with worker bees ‘appointed’ for service in caring, feeding, cleaning and fighting. But for all that bees are social insects, Laline Paull’s novel “The Bees”, depicting an alien totalitarian state, is a warning against drawing too close a parallel.
HONEY & BUMBLE
Brood laying increases further; it is about a six-week period from the beginning of rapid colony build-up to the beginning of the spring nectar flow. Monthly inspections of honeybee hives on milder days are generally sufficient in winter. March and April can be unpredictable in weather and scarce in pollen, so during spring build-up, weekly inspections of food levels are needed. But the hive must not be opened for too long on cooler days, or the nurse bees clustered over the brood to keep it warm will be disrupted and the brood will chill.
Meanwhile, the queen bumblebee sits on her brood to keep them warm. Although honeybees and bumblebees are closely related, their winter behaviour is very different. Bumblebees do not maintain colonies throughout the winter. The last bumblebee brood of the summer contains a number of queens, who mate and find a nest in which to hibernate.
In the spring, the queen builds a ‘honey pot’ from wax to store honey. She collects pollen and mixes it with more honey to make a pile of ‘bee bread’. Here she lays her eggs and nurtures developing bumblebees, while eating her stored honey. The first brood will be mostly workers, who can take over foraging while the queen continues to lay eggs.
There are at least 1,500 species of insect pollinators in the UK: a few species of selectively-bred honeybees, almost all managed in hives with very few colonies in the wild; and mostly native species of bumblebees, solitary bees, moths, butterflies and hoverflies.
Honeybees are not essential pollinators for the maintenance of natural biodiversity; the main problems are the pressures on these wild pollinators. Most concerns relating to honeybee health are veterinary or husbandry problems. If their foodstocks are low, they can be fed on sugar water. If they are badly managed, their diseases like Nosema can spread to wild bees. But pesticides are a threat to all pollinators.
Pesticides are certainly a focus among campaigning groups. Spring, after the frosts are past, is the time for sowing maize and soybean. In the US most of the seeds are coated with neonicotinoids, insecticides which were introduced in the mid-1990s as a less toxic replacement for the mass spraying of organophosphates and pyrethroids.
Neonicotinoids applied as seed coatings or as granules to the soil are effective. The questions under debate are: how toxic they are for pollinators; and whether their use should be limited. Although it is not much of a debate with campaigners shouting on one side, big chemical companies lobbying on the other, and researchers caught in between.
In January 2013, the European Food Safety Authority (EFSA) reported on the risks of the three main neonicotinoids.1 In response, the European Commission recommended a restriction of their use across the European Union, and 15 of the 27 EU Member States voted for a two-year embargo on coated seeds starting on 1 December 2013.
There was a mixed reaction from scientists: some hailing a victory for the precautionary principle,2 which should underlie environmental regulation; others concerned that the ban could overshadow other risk factors.
The science is complicated by the glorious complexity of bee colonies and biodiversity in the field, and the divergence between lab studies and the ‘real world’, such as whether the dosages studied are representative of those applied in practice.
It seems fairly clear that, despite the emotive messages of the campaigns in the run up to the ban, neonicotinoids do not kill either honeybees or wild bees directly. However, it is less clear whether they have an effect on other behaviours and attributes: vulnerability to pathogens; foraging behaviours, such as navigation; colony development, such as ability to produce queens and overall number of births; or overwintering success.
So for example, a critical analysis of research into the interactions between pesticide exposure and pathogen infection, published in July 2015, stated that these remain unclear. On the other hand, in what they claim was the first ‘real world’ experiment on the effects of neonicotinoids in bees, published in April 2015, scientists from Lund University in Sweden found reductions in wild bee density, solitary bee nesting, and bumblebee colony growth and reproduction. They found no effect on honeybees, which are at lower risk as they are able to metabolise neonicotinoids more quickly.
FRYING PAN OR FIRE?
What is clear is that if the ban continues, farmers must not be permitted to revert to using the even more harmful organophosphate and pyrethroid pesticides, but turn instead to integrated pest management3 involving preventive cultural practices, and mechanical and biological controls.
It also seems clear that pesticides are not the most important driver of decline. The main threat to pollinators and pollination is habitat loss as a result of agriculture intensification, urban development, increased frequency of fires and climate change.
Bees fly two miles in any direction in search of pollen and nectar, but under US-style crop monoculture, bees have only one pollen source then face starvation. So colonies are trucked across states, leading to the occasional amazing news story of crashes involving millions of bees. These bees still have poor nutrition and are stressed, making them more vulnerable to pesticides and diseases. Transporting the hives can also spread the pathogens to local bee populations.
In England and Wales, according to the “State of Nature” report from the RSPB in 2013,4 the area of lowland meadow plummeted by 97% between the 1930s and 1984. Three-quarters of the bumblebees’ preferred food plants have declined over the past 80 years.
Climate change adds to the pressure in the spring and summer. Temperature increases are triggering wild bees to emerge 7-10 days earlier in the year per decade, while flowering is shifting by only 4-5 days. The disjunct between activity and food could tip species over the edge. In Illinois in the US, for example, half the bee species have become locally extinct as the pattern of which plants were pollinated by which bees altered over 120 years.
Bumblebees evolved in a cool climate and are intolerant of heat. In warmer southern habitats, they are being killed outright by extreme temperatures, and indirectly by the effects of heatwave and drought on their food sources. But to the mystification of researchers they are not shifting north to cooler climes.
In the UK the summer heyday is next, the season of heavy humblebees and drowsy dumbledores. Plants are desperate to reproduce and are pumping out pollen. Bees gently potter from flower to flower; no need to hurry as there is plenty to go round. As Emily Brontë describes in Wuthering Heights, “[T]he pleasantest manner of spending a hot July day was lying from morning till evening on a bank of heath in the middle of the moors, with the bees humming dreamily about among the bloom, and the larks singing high up overhead…”.
There is a contentment, perhaps the remembrance of a lost golden age or a sense of time slowing to a standstill: “yet / Stands the Church clock at ten to three? / And is there honey still for tea?” (Rupert Brooke, “The Old Vicarage, Grantchester”).
Honey never spoils, and is a marvellous gift in its sweetness and healing properties. But its production requires intensive resources; it is only a small hop from daydreaming amidst the heather to hard economics. The average worker honeybee produces only one-twelfth of a teaspoon of honey over her lifetime. She lives about six weeks, and the queen must continually lay eggs to replenish the hive. To make a one pound jar of honey, bees must visit 2 million flowers.
Yet honey is only a tiny part of bees’ contribution to our diet. According to the UN, some 70% of the 100 crop species that provide 90% of the world’s food are pollinated by bees. The value of insect pollination depends on the reliance of crops on pollinators to grow and fruit, and the contribution of the sale of these crops to the economy. Bees contribute $200-500 billion to the global economy each year.
In the UK, bees contribute £650m (about $1 billion), £150 million more than the Royal Family contributes through tourism, and provide us with most of our carrots and cabbages, apples and pears, raspberries and strawberries. Just 2% of bee species in Britain do 80% of the crop pollination. We are unlikely to run out of food if pollinator populations decline, but it will be more difficult and expensive to produce. It is in our interests to conserve all our pollinating insects in case they are needed as the climate warms and crop varieties change.
Just as importantly, insect pollination supports biodiversity and healthy ecosystems, helping plants to produce fruit and seeds for birds and animals. They are truly a wonder of God’s created web of life. They have a priceless value as part of our natural world, of which we are also part, and as such they contribute to our well-being.
Around the world, bumblebees and other wild bees are declining in both diversity and abundance. Some 9% of the nearly 2,000 species on the European Red List of Bees are threatened with extinction.5 Of our 178 bee species, the RSPB have found that more than half are decreasing or strongly decreasing in number.
Colony collapse disorder has meanwhile struck managed hives. It is not unusual for beekeepers to experience losses particularly over the winter, but CCD can strike at any time and doubled the expected rate of loss between 2006 and 2013. Also known as disappearing disease, spring dwindle, May disease, autumn collapse, and fall dwindle disease, the majority of worker bees disappear and leave behind a queen, food and a few nurse bees to care for the remnant.
Scientists disagree on the cause. The main candidate is the parasitic varroa mite attacking a colony already under stress, but proposals also include emerging diseases, pesticides, stress of transportation, habitat changes, poor nutrition, exceptionally severe winters, or a combination of factors. The lack of understanding means CCD is still a concern, even though colony loss was lower in 2014-15.
PLANS FOR POLLINATORS
Our lack of complete understanding should not stand in the way of wisdom, and applying what we do know in caring for the future of bees. There is value in the UK response, even though it is bound by national boundaries while biodiversity is not. Defra has a ten-year National Pollinator Strategy in England6 and the Welsh Government has an Action Plan for Pollinators,7 but there are no strategies thus far in Scotland or Northern Ireland.
The National Pollinator Strategy aims to: support pollinators on farmland, in cities and the countryside; enhance the response to pest and disease risks; raise awareness of what pollinators need to survive and thrive; and improve evidence on the status of pollinators and the services they provide. The outcomes would be: more flower-rich habitats; greater resilience to climate change and severe weather; no further extinctions; and enhanced corporate and public awareness.
Defra also launched a Bees’ Needs in 2014, a public call to action: grow more plants that provide pollen and nectar; leave patches of land to grow wild; cut grass less often; avoid disturbing or destroying nests; think carefully about whether to use pesticides.
As late summer turns to autumn, bumblebee queens will be laying eggs that become the next generation. The new queens would appreciate a nest from an upturned pot stuffed with straw, and other pollinators a homemade hotel. Beekeepers will be checking the health of their queens. They live five years, but vitality decreases with age and many are replaced every other year. Requeening can be done in autumn if there is a dependable nectar flow. It is also the time to check for broken combs and evidence of disease, and sufficient food stores to see the winter through.
And so when the streets buzz with Christmas shoppers once again, honeybees will form their winter cluster around their queen, and bumblebee queens will go back into hibernation.