October 11, 2016

A Look at Pollen and the Role of Bees in Pollination

Pollen is the yellow, white, or brown powder-like substance that is produced in the stamens (or male parts) of a flower, pollen grains come in a wide variety of sizes and shapes although most are spherical. Each species of plant pollen has its own unique surface marking and each grain has a thick protective coating to protect the male gamete, or sperm. Pollen can be either light and dusty and easily blown in the wind or heavier and stickier.

The wind or air-borne type is called Anemophile (wind loving) pollen and it is this that gives you hayfever. The heavier stickier type is called Entomophile (insect loving) pollen and it is this type that bees collect.

Pollination

Pollen is used to fertilize the plant by the process of pollination. There are three different types of pollination, self-pollination, pollination from a different flower within the same plant and pollination from a different plant (known as cross-pollination). Cross-pollination is essential for the long-term genetic diversity of the plant and the future success of the species. Pollen produced in the flowers’ stamens is transferred to the pistils or female plant parts. Depending upon the weight of the pollen grain, pollination is either wind or creature borne. For example grasses and wheat are examples of wind pollinating plants, whilst fruit trees, having heavier stickier pollen require the help of insects or birds. Each tiny grain in the pistil grows into a long tube called a pollen tube, growing until it reaches the plant’s ovary.The male gamete is then released into the ovary. Pollination produces fruits and seeds and the pollen also contains the plant`s genetic code.

Bees and their role in plant pollination

Bees are without doubt the most abundant pollinators of flowering plants in our environment. 70% of all flowering plants only survive as a result of bees and other pollinators and fruits and seeds from insect pollinated plants account for over 30 percent of the foods and beverages that we consume. Beyond agriculture, bees are a vital part of most of our ecosystems as fruits and seeds derived from insect pollination are a major part of the diet of approximately 25 percent of all birds and mammals, ranging from the smallest mouse to the largest grizzly bear. However it is not just our honey bees that are having problems many of our native bee pollinators are at risk. Habitat loss, pesticide use and human-introduced diseases are all contributing to the decline in bee numbers.

As a result of the problems with commercially managed honey bee colonies, many species of bees which were until recently considered to be wild bees are now being bred commercially for crop pollination. These include bumble bees, leafcutter bees, mason bees, sweat bees and many other species. There is growing concern however that intensive farming of these species is now leading to some of the problems found in honey bee colonies, in particular diseases and to make matters worse these are unfortunately being transferred from the managed bees to the wild members of their species. Perhaps we just need to learn to leave nature alone to carry out the job she has been performing well for millions of years, without the help of man or pesticides.

Honey bees and pollen

As well as collecting nectar, honey bees collect pollen, storing it as they go from flower to flower in specially designed sacs on their back legs. It is this efficient collection method which makes honey bees less effective pollinators than some of their messier relations, who trap pollen in hairs on their body and transport it that way, dropping plenty as they go.

Honey bees unlike ants and wasps are vegetarians and rely on pollen for protein, which is essential for a healthy body and for the development of their young, in particular bee larvae. Pollen can contain up to 35% protein, in addition it also contains vitamins, enzymes and starch. Back at their hives the honey bees store it in special cells, adding a small amount of honey which prevents it from going off.

By Maggie Roberts

For more information about Beekeeping see http://www.beekeepingbeesandhoney.com