bees role in the environment
It is through pollination that plants are fertilised and able to produce the next generation of plants, including the fruit and crops we eat.
Since plants can’t move, they have to employ other tactics to ensure pollen is carried from flower to flower.
Around 75% of crop plants require some degree of animal pollination, including many of our everyday fruit and vegetables. Of all the different animals and insects that serve as pollinators, the most important are bees.
In the past we relied on wild bees to pollinate our crops but wild bee populations are now in decline due to disease, extreme weather, competition from invasive species, habitat loss and climate change.
To make up for the decline in wild pollinators, farmers buy in commercially bred bees and put them on farmland hoping that the bees will forage on the crops they want pollinated. This method is expensive, but the farmers crops would not be pollinated without it.
The video below shows a short documentary on the relationship between beekeeping and food production:-
Flowers and Pollination
Flowers may look very pretty, and are most of the reason that we have them in our homes, but the flowers serve a really important role to the plant; they are the plant's reproductive system.
When a living thing makes a new individual like itself, this is called reproduction. To reproduce, most organisms produce special sex cells called Gametes.
In an animal, the male gamete is the sperm cell and the female gamete is the egg cell.
In a plant, the male gamete is Pollen and the female gamete is the Ovule.
To reproduce, the male sex cell must meet and join with the female sex cell.
Flowers come in thousands of different colours shapes and sizes, but all flowers have the same basic structure:-
Parts of a flower and their function:-
Sepal - Green cover that protects the flower as it develops.
Petal - Brightly coloured to attract Insects for pollination.
Stamen and Anther - The "male" part of the plant; the stamen supports the anther, where the pollen is produced.
Stigma, Style and Ovary - The "female" part of the plant; the sticky stigma collects pollen, which passes down the style to the ovary, where fertilisation takes place.
The parts of a flower shown above all work together as the plant's reproductive system. However, the plant cannot just reproduce on its own, they need help. When Pollen is transferred from the male to female parts of a flower, it is known as Pollination.
Plants can be pollinated by two methods:-
Wind Pollination - The pollen is light enough for the wind to blow the pollen onto other flowers.
Insect Pollination - The pollen is sticky, insects (or other animals) feeding on the nectar in the flower carry the pollen from one flower to another.
In this course, we will obviously be focusing on Insect Pollination.
Insect Pollination is the process of pollen being transferred between plants by insects or other animals (such as birds or bats). In order to get carried by an insect, the pollen must be very sticky.
As the plant needs insect to carry its pollen between flowers, the flow has to be very attractive to insects. A plant does this by making lots of sugary nectar that the insect will feed on, as well as having bright colours and sweet smell.
Plants that are pollinated by insects include:-
The differences between insect pollinated and wind pollinated plants are shown in the table below:-
Pollination occurs when pollen from the anther of a flower was transferred to the stigma of another flower.
Once the pollen reaches the stigma, the process of fertilisation can begin:-
Once fertilisation has occurred, the flower changes completely. The ovary swells in size to form a fruit and the fertilised ovule becomes a seed.
The video below gives an overview of pollination:-
Bees and Pollen
Bees don't just visit flowers and gather pollen by accident to help with pollination, however. The Pollen is of vital importance within the Hive. The Pollen is stored within the comb and used to produce "Bee Bread". Bee Bread is the main food source for Worker Bees and Larva (apart from Queen larvae).
Bee bread is a mixture of pollen and nectar or honey. The exact composition of the bee bread varies depending on the plants that the bees forage from. This not only changes at different locations but also with the seasons and even at different times of the day.
Scientists have found that the bees add extra secretions and micro-organisms (such as bacteria and mould) to the bee bread. These additions help break down some of the pollen and release amino acids and other nutrients from the pollen (and has similarities to sour dough bread making).
The colour of the Pollen brought back to the colony will depend on the flowers that the Bees have been foraging from. If the foragers visit only one pant species, the pollen will be of similar colour but if they visit a range of plant species the pollen stores will be multicoloured:-
Pollen from one flower source
Pollen from multiple sources
Bees carry the pollen in specially evolved areas of their hind legs called the Pollen Basket. The Bee uses the fine hairs on the lower section of the leg to brush the pollen into the long curved hairs on the tibia, creating a secure store for the pollen.
Nectar, after foraging, is transported to the hive in a forager bee's honey stomach (or crop). The crop doesn’t digest nectar and can hold up to 70mg, weighing almost as much as the bee itself. As soon as the nectar enters the crop, enzymes begin to break down complex sugars into simple sugars (glucose and fructose).
Once the forager bee arrives at the hive she unloads the collected nectar to a house bee through mouth to mouth contact (trophallaxis). The house bee ingests the nectar and her own enzymes further break down the sugars. The nectar gets passed between multiple house bees and as it does the water content reduces to about 20%. The nectar then gets deposited into a cell for storage.
The bees fan the nectar and this action, along with the natural temperature of the hive helps to evaporate the remaining water content. As this happens the sugars thicken into a substance that is known as honey.
The honey is stored unsealed until the cell is full at which point the bees will seal the cell with beeswax in order to protect the stores for later.
The video below shows the process of Honey production from flower to jar:-
Due to the Nectar sources changing with the seasons, so does the colour and flavour of the Honey that is produced.
The flowers available to Bees varies across the country, depending on what can grow in that area.
The table below shows how the foraging flowers change over the year, local to Stirling:-
The poster below shows more generalised foraging from across Scotland:-
The Honey produced by Nectar from mainly one plant are known as varietal Honey. The image below shows the range of colours these can be:-
Along with the differences in colour, there is also a large range in flavours within varietal Honey. The diagram below shows a simple tasting guide covering some common plants and trees that Bees forage upon:-
To read the above diagram, start at the edge and read in towards the center. For example:-
Blackberry nectar gives Honey that has flavours that are Vanilla, Berry and Fruit.
Buckwheat nectar gives Honey that has flavours that are Earthy, Molasses and Confection.
How to taste honey
Varietal Honey shows complex flavours and Beekeepers around the world hold Tasting sessions for their Honey, just like Wine or Whiskey tastings. Below is a short procedure for Honey Tastings:-
Pour a small amount of Honey into a glass.
Observe the colour and clarity of the Honey.
Warm the glass in your hands and smell the honey, taking note of any scents you notice.
Taste a small amount of the Honey, letting it sit on your tongue, taking note of any flavours you notice.
Finally, take note of how long the the flavours last. Some Honey flavours are short whereas some linger and change.
Between each tasting, eat unsalted crackers and sip room temperature water to reset your palate.
The video below shows an example of a Honey Tasting:-