Different insects tend to visit different flowers, and are
better suited to pollinating some than others. Tomatoes and
blueberries, for example, are best pollinated by bumblebees,
while mason bees are excellent at pollinating apples. We have
tiny flies to thank for giving us chocolate, for it is they that
pollinate the cacao tree.
Disturbingly, however, many of these pollinators are in
decline. Some species, such as Franklin’s bumblebee (Bombus
franklini), once found in the western US, are now extinct.
Others cling on to existence, but are far less common than
they once were. Populations of insects such as the Monarch
butterfly (Danaus plexipus) in North America, or the great
yellow bumblebee (Bombus distinguendus) in Europe have
dropped by about 90 percent.
This is a matter of the utmost concern, for we cannot feed
a growing global human population without our insect allies.
Collater al Da mage
What has happened to our pollinators? The answer is
complex, and there is no one villain to blame; humans have
created a hive of problems for pollinators.
The biggest driver of pollinator declines is a lack of wild
flowers. Farming has changed enormously in the last 100 years,
from an age of low-intensity farming of small fields to an era
of vast crop monocultures, fields that stretch to the horizon,
with not a weed or wildflower to be seen. Some crops, such as
oilseed rape or sunflowers, provide food for bees, but only for
a week or two, and for the rest of the year there is nothing for
them to eat. Maintaining these fields free from weeds is greatly
aided by modern herbicides such as glyphosate, which allow
farmers to grow perfect monocultures of crops.
To make matters worse, humans have inadvertently spread
bee diseases and parasites around the globe with domestic
honeybees, and also with commercially-reared bumblebees
that are used for tomato pollination. For example, the careless
movement of bees has spread the Varroa mite – a tiny blood-
sucking parasite which attacks honeybees – to almost every
country in the world. Similarly, wild Japanese bumblebees
now have to cope with attacks of European tracheal mites,
which infest their breathing airways.
To add to these problems, the modern world is full
of insecticides that are directly toxic to bees. Farmers
spray their crops with organophosphates, pyrethroids and
neonicotinoids, all chemicals intended to kill pests, but
which inevitably cause collateral damage. The neonicotinoids
are particularly insidious, for they are persistent and systemic,
getting into plant tissues and then into their nectar and pollen.
In gardens and towns, a similar barrage of chemicals is used
to kill garden pests, mosquitoes, flies, ants, or fleas on
domestic animals.IMAGE © GETTY IMAGES