By Fiona Hodge

In order to reproduce plants need to get their sperm, contained in pollen grains, to the eggs in the base of another flower. The vast majority of plants rely on insects as a pollen messenger. Insects such as flies, beetles, butterflies and bees visit flowers for nectar and in the process transport the pollen grains. The delivery of pollen is called pollination, and successful pollination results in seeds, fruit and eventually offspring.

Scientists have found declines in both the diversity and abundance of these insect pollinators. Scientists attribute their declines to the loss of insect friendly habitat, a result of intensified agriculture, and the wide spread use of insecticides. This is bad news for all insect pollinated plants.

The declines of wild pollinators may have been masked by the industrialisation of pollination in agriculture. Hives of honey bees are now loaded onto trucks and driven miles following the flowering crops. Crops as diverse as kiwifruit, cashew nuts and broccoli are pollinated by these travelling honey bees. The scale of this is incredible. Over one million hives were brought to California to pollinate the almond crop alone last month.

There is also concern over the health of these honey bees. Worker honey bees have been disappearing, leaving their hives to collapse (Colony Collapse Disorder). Over a third of American hives were lost this way in the winter of 2008, and collapsing hives have been found all over the world. Scientists are yet to pin down the cause of this but suspect a variety of interacting factors. These include the invasive Varroa destructor parasitic mite, the viruses this mite spreads, pathogens, insecticides, and stresses from the diet and travel in industrialised bee keeping.

The collapsing hives have prompted researchers to look into the efficiencies of wild pollinators in agriculture. Researchers found wild pollinators, including bumble bees and flies, were just as efficient at pollinating New Zealand Pak Choi crops as the honey bee. Why spend money trucking bees when, with a bit of land and a bit less insecticide, nature could do it for free?

Flowering plants aren’t the only ones that rely on other species for services often considered invisible. Wild and domesticated insects pollinate our crops, riverside plants keep our whitebait eggs damp while they wait for a full moon, forests protect from erosion and slow flooding, and estuaries purify our water. We need our biodiversity more than we often realise.