Bee Blog May 2016
The BC weather site is already issuing pollen warnings along with their forecasts and all those who suffer from hay fever will be diving for the nasal spray and various others of the manifold reliefs for the menace of pollen. It’s called hay fever because the main culprits are grasses. It may be a nuisance to over a million people in the UK each year, but pollen is what enables plants to reproduce, and without it we would be sunk.
A lot of plants are pollinated by insects, but hay fever is caused mainly by pollen which is borne on the wind. Wind pollination is a very chancy affair indeed. Within each male flower, or cone of the yew tree, there are approximately 50,000 grains of pollen, and on a large yew tree there are hundreds of thousands of these cones. The female flowers of the yew tree produce a small droplet of liquid which will trap the pollen grain provided the pollen finds its way to that female flower. The chances of it doing so are far less than one in a million, and then it has to land the right way up.
Self pollination is a minority way of ensuring reproduction and, in this case, the flowers contain elements of both sexes; but the method of pollination that we all know most about is insect pollination, and everybody automatically thinks of honey bees. The truth is that honey bees are only one of many species of insects including flies, beetles, butterflies, wasps and moths that play a part in the pollination, or fertilization, of plants. As insects visit many flowers in order to gain nectar, or pollen, or both, they pass pollen from one plant to another, because plants that rely on insects have made their pollen so that it will stick to the bodies of their visitors, and if you look at the picture you will see that some of the pollen grains have prongs to facilitate this. When bees, in particular, find a good source of food, they tend to pass the word around, and all their friends will be visiting that one species of plant, and the chances of a perfect pollination are increased dramatically.
Pollen is so widespread that it is reckoned that every square centimeter of the UK has at least 5000 pollen grains on it. So when you dust the sideboard next, remember that you have probably moved about 36 million pollen grains. That’s a tremendous amount of pollen.
Pollen has been with us for a long time and scientists who study it (palynologists) are frequently asked to identify traces of dust from the clothes of crime victims, or suspected perpetrators. As pollen grains vary so much in their shape and size, it is often possible to tell exactly where the pollen came from, but also at what time of year it was acquired. That way criminals can be associated with a particular place, at a particular time.
Pollen deteriorates very slowly indeed and archaeologists studying the pattern of habitation in Shetland thought that the only fuel for fires was peat, but, as charred wood was found in old fire pits, they realised that some of the first settlers de-forested the islands and used the wood to keep warm. Only then did they turn to peat, but they also cleared the land of trees so that they could grow wheat. They know this from pollen found at certain depths in the soil and around human settlements. As the quality of soil was depleted, they grew a crop that needed less nourishment, and turned to barley, which was also realised as a result of finding the pollen. Unfortunately, barley isn’t a very good food product. It is much better known for brewing beer. So we have absolute proof that the inhabitants of Shetland took to drink a very long time ago. Carbon dating allowed them to tell that one set of remains dated from 1149, but pollen samples found in the nasal area of the skeleton told them that the person died in July of that year.
Pollen can also be used for identifying the origin of honey, but a lot of commercial honey producers filter out as much of the pollen as they can to stop the honey from setting. This masks the origin of the honey, but some unscrupulous companies, far, far away from the UK, add pollen from a favourable source and then claim that the honey comes from another part of the world altogether. Even more unscrupulous people simply add pollen to corn syrup, claiming it to be the one thing that it isn’t – honey. There is one easy test to foil them though. Light shone through honey will bend (refract) in one direction, and through corn syrup will deflect in entirely the other direction.