Why bees are critical for growing your own

The concern for declining bee populations is driving home gardeners to attract pollinating insects including bees, and become backyard beekeepers. But why are bees so critical that they need our special attention?

The bottom line is that bees are vital for pollination of flowers on many food plants. Indeed, around 35 percent of global food production is dependent on bees and other pollinators. Without bees, we’d have no chocolate or honey, but we’d also have a lot less fruit and a dearth of some vegetables.

Food plants that require cross pollination (that is the movement of pollen from one flower to another) and rely on bees include most apples, some pears and cherries, blueberries and many other fruits that are rich in vitamin A and folates such as rockmelon and citrus. Some edible seeds and nuts such as quinoa, sunflower and almonds need bee pollination, as do some ‘fruiting’ vegetables including beans, peas, tomatoes and capsicum.

Even plants that don’t need bees to produce the parts we eat (such as lettuce, spinach and asparagus) need pollination to produce seeds to grow new plants or develop new varieties.

 Bee pollinating passionfruit flower.

About pollination

Pollination is all about reproduction. Pollination describes the transfer of pollen (the male part of the equation) to the stigma (the female part of the flower). Successful pollination leads to fertilisation, which in turn means seeds and fruit.

As bees fly from flower to flower, they are carrying pollen. If you look at a bee buzzing about in your garden you may notice yellow or white grains packed around their legs or dusted on their bodies.

Many plants can only reproduce (that is, produce seeds which are often encased in fruits we eat) if they receive pollen from another compatible plant. This mechanism evolved to prevent self-fertilisation and increases genetic diversity. In some plants, such as kiwi fruit, male and female flowers are even carried on separate plants. Pumpkins, zucchini and squash also have separate male and female flowers, and so rely on bees for cross-pollination and the formation of fruit. Without bees, we must hand-pollinate to get fruit to form.

As well as being required for pollination, research shows that many fruits have better size and shape if they are bee-pollinated. Strawberries in particular have been shown to produce larger fruit with good bee pollination.

 Bee pollinating strawberry plant.

Factors in bee decline

There is no one single factor causing bee populations to decline. Disease, pests, starvation, weather extremes and chemicals are some of the factors that are combining to weaken and kill bees. A condition called Colony Collapse Disorder was first highlighted in the United States 10 years ago when beekeepers were noticing previously busy hives completely empty of worker bees.

Even when bees are healthy, as they are in Australia, extremes of heat and cold, drought (bees need water to drink and to keep their hives cool), lack of food and the widespread use of pesticides (insecticides and fungicides) all reduce bee numbers. Even chemicals sold as organic or ‘safe’ can be toxic to bees.

If it is necessary to use a garden chemical that could be harmful to bees and other beneficial insects, avoid applying it when bees are foraging or look for bee-safe chemicals such as Bt (Bacillus thuringiensis) or Dipel, which kills caterpillars only.

 Bee flying towards a plum blossom.

To learn more about attracting bees to your garden and plants bees like, click here.

The Wild Pollinator Count occurs in spring each year. To find out how you can take part, click here.