Plants and bees; a 100 million-year-old love affair

Before around 100 million years ago, plants and trees had been limited to wind-borne pollination, which is relatively inefficient. It requires the generation of vast amounts of pollen to be then released by the plant to guarantee reproduction.

Around this time a few plants evolved flowers containing pollen and nectar to entice insects to visit them to feed. The trade-off for the plants in generating this food was to use the insects as vectors, exchanging pollen between flowers and thus facilitating sexual reproduction in a much more efficient manner.

Plants and their pollinators have evolved together over the last 100 million years, establishing complex relationships in almost every land-based ecosystem. Plants and trees have developed complex flowers with a vast variety of designs and colours as well as moving in the wind to attract passing pollinators to visit. Many also produce nectar at particular times of the day so that insects can stay within an area for long periods pollinating many different plant and tree species.

The tarantula hawk wasp is one of many other insects that feed on pollen and nectar.

Bees are the largest and most important group of pollinating insects and are present in almost all continents across the world. There are over 25,000 species ranging in size from 2mm to 4cm big and can be broadly split into two groups, solitary bees and social bees including Bumblebees and Honeybees.  All exist solely on a diet of pollen and nectar gathered from local plants and trees.

Different pollinators have different flower preferences which they like to feed on, and this is determined by their tongue length and time of year they are active. Long-tongued bees prefer long tubular-shaped blooms or trumpet-shaped flowers, often flowers which hand like bells such a Fox Glove, Penstemon and Comfrey. Short tongued bees prefer simple open flowers with easy to access nectar such as orchard tree blooms, Dandelion and Daisies. Honey bees are generalists, having short-ish tongues, being active most of the year and therefore can feed on a wide range of flowers.

Short tongued bees prefer simple open flowers with easy to access nectar.

They also developed a sophisticated use of pheromones to indicate when a particular flower has been visited and emptied to make foraging more effective.

The relationship between plants and pollinators has reached the point where over 90% of all plant-life across the planet reproduces through pollination by insects (and occasionally animals).

Pollen is a rich source of protein, fats and vitamins and is particularly important for bees and other insects when raising young but also used for body repair, gaining weight prior to winter and for entering breeding conditions. Nectar is a source of high energy carbohydrates in the forms of various sugars. Bees use nectar to fuel their bodies, power their flight muscles and other metabolic functions. Many bees also consume nectar and convert it into wax for use in nest construction, forming cells or comb to raise their offspring or store food for later consumption.

Honey bees collect vast quantities of nectar, over 500 lbs per colony per year and turn some of this nectar into honey which they store to eat during the winter months when the weather is too cool for them to fly and flowering plants are in scarce abundance.

When do bees need access to flowers?

Pollinators are most active from March to October and require pollen and nectar throughout this active period. Some species such as the Buff Tailed Bumble Bee are active all year round in southern parts of the UK and rely on winter flowering plants such as Mahonia, Viburnum tinus and Winter Honey Suckle for forage during the cold months of winter. These bees rely almost exclusively on exotic garden plants for survival during the winter months when our native plants are mostly dormant.

Do bees discriminate between native plants and exotic flowers?

The majority of adult insects, including most bees, do not care whether or not a plant is native or non-native as long as its pollen and nectar are produced freely and they are of good quality. For nectar, this means a high sugar content and for pollen, it means a high protein content and presence of fatty acids and oils.

For many years conservationists and wildlife gardeners have advised that natives are best planted to attract and provide food for pollinators in our gardens, but recent research increasingly supports the opinion that mixtures of native and non-natives are actually better. This is because the majority of our native flowers are short-lived and flower in spring and early summer while many non-native plants help to fill the late summer and autumn gap, extending the flowering season and providing food for pollinators at a time of year when they struggle the most to meet their nutritional needs.

How much forage does a bee hive need?

This is a difficult question to answer but estimates suggest that a typical colony of honey bees requires around 500lbs of nectar and 100lbs of pollen annually just to meet their own reproductive and winter survival needs. This is more than a bathtub’s worth of nectar, and is made from billions of flower visits by the thousands of workers that make up the colony.

And this is before the bees make any surplus honey for the beekeeper to harvest!

To make a lb jar of honey it is estimated that the colony will visit between 2-4 million flowers and fly up to 55,000 bee miles – that is twice the distance around the globe. In addition to the nectars which go into producing honey, the bees also need to consume a lot of nectar themselves for the energy needed to generate heat and circulating air currents within the hive. This drives off the water content within the nectar and transforms it into honey. Thus the amounts of nectar gathered in production of the surplus honey the beekeepers take as a honey crop are astronomical and beyond the comprehension of most people.

To gather this vast quantity of nectar and pollen the bees must visit many billions of flowers and spread themselves over a large area. A colony will typically forage within a 3km radius from the hive but when forage is in short supply they will fly as far afield as 12km to find rewarding patches of flowers.

There can never be enough flowers to support our pollinators!

How can I best help bees?

Honey bees are currently faring well in the UK thanks to the efforts of an increasing number of amateur beekeepers who tend to their needs. Colony numbers are once again increasing with around 225,000 hives registered in the UK and numbers of beekeepers have risen from around 8,500 to over 25,500 in less than a decade.

Whilst honey bees have beekeepers to help them stay fit and healthy, finding sufficient forage and in sufficient variety to provide them with a balanced diet is a constant challenge, so planting the right sort of flowers for them in our gardens is a great way to help them.

Many of our 274 species of wild bees, such as the Bumble and other solitary bees are in serious decline in the UK.

Many of our 274 species of wild bees present in the UK, for instance the Bumble Bees and Solitary Bees, are however in serious decline and don’t have the luxury of beekeepers to tend to their needs. Again the best way to help them survive and prosper is by planting the right kind of flowers for them. Plant a variety of flowers in your garden to cater for a variety of different bees, accommodating different tongue lengths and choose a succession of flowering plants that will provide forage throughout a long season. You can further assist solitary bees by erecting nesting houses for them to rear their young in. These are available to buy from many good retailers, but you can also make your own for little or no money.

Here are some fact-sheets showing you how to help bees.

Guide to creating homes for Solitary Bees.

You can help provide solitary bees with valuable nesting sites by creating easy to make bee hotels or artificial nesting mounds.

Guide to planting for bumble bees.

Guide to planting for solitary bees.

Trees for bees.

Shrubs for bees.

The Knaphillian extends huge thanks to our friend Simon Cavill, an experienced beekeeper for over 15 years, for writing and contributing this article. Simon keeps a number of hives to the highest standards in old orchards surrounding his home in Hampshire. As a champion of British beekeeping, Simon is an ex Trustee of the British Beekeeper’s Association and is studying to become a “Master Beekeeper”.  You can read the latest tales of his bees in his blog.

Simon and Caroline Cavill.

Simon and his wife Caroline started an independent British skincare company, Bee Good, in 2008 that harnesses the potent properties of honey bee ingredients and expertly blends them with naturally active botanicals to create a range of gentle yet effective skincare for women and men of all ages and all skin types. You can visit their website here.

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