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"If somebody asked you what bees do,
you'd probably imagine a little insect in your
garden going from flower to flower,
collecting nectar to make into honey to
put on your toast. But of the 20,000 or
so species of bee, only seven of them
produce honey. But many of the others play
a key role in producing the food that we eat
– for example, oranges to make into juice,
strawberries for jam, or beans for coffee."
Bees and other insects such
as flies and wasps help us grow food
by pollinating flowers. When they do this
they transfer pollen from one flower to
another, which fertilizes the flowers and
means they grow into fruit and seeds.
Insect pollination is vital to the
production of many crops, and improves
the quality and yield of others. As the
world population grows, we're going to
need to produce more food – which means
we'll need more pollinators. But around
the world we're seeing a general decline
in insect numbers – exactly the opposite
of what we need.
So in our team here at the University of
Cambridge Department of Plant Sciences,
researchers including Jake Moscrop are
trying to uncover what insects like
about flowers. "I want to find out if we
can make crop flowers easy for insects
to find, more efficient at being
pollinated, and more rewarding for the
insects which visit them. If we can identify
characteristics which help insects find
flowers faster, and and interact with them
quicker, then we can make better use of
insects visiting our plants. Plus, if we
can make those flowers more rewarding
for the insects by increasing the amount
of pollen and nectar, we can help to
support wild insect numbers."
Plants including strawberries, broad beans
and coffee are pollinated by insects,
and flowers are the plants' advertising
display. They're there to be as
attractive as possible to those insects.
They do this with a remarkable array of
features – not just size and colour, but
pattern and smell too. Once an insect has
landed on a flower, the advertising
continues close up. Some plants have
nectar guides, which show the way to the
reward, or textured petals which help
insects hold onto a flower in just the
right way.
To be able to tell plant breeders what
they should be looking for if they want
to select plants which are more
appealing to pollinators, Jake needs to
know what insects think about flowers
from varieties which already exist.
Working with bean flowers, he
painstakingly looks at their size and
shape, along with how big the petal spots
are. He also looks at how much nectar and
pollen each flower produces, to see how
rewarding the flowers are for the
insects that visit them. "Once I've found the
limits of flower features which already
exist, I can use our bumblebee lab to ask
the bees what they think. We use bumblebees
because they're really easy to work
with, and you can buy small colonies
commercially. They're actually what some
farmers use in their greenhouses to
supplement wild insect numbers. I use
plastic models of flowers to test the
bees' reaction to just one thing – in this
case it's the size of spots on the
petals. On the flowers which have big
spots we've put a sugary liquid, which
the bees like, and on the flowers with
small spots we put water, which the bees
like less. This experiment tests whether
the bees can tell the difference between
the big spots and the small spots. If
they can then we'd expect the bees to
learn over time that the sugar can be
found in flowers with big spots and to
ignore the flowers with small spots. Once
we know this we can move on to
experiments seeing which size spot helps
bees move between flowers faster – and
spot size is only one of a number of
features of the flower we can test, so
there's lots to find out."
All this knowledge means we can work with
plant breeders to produce crops which use
pollinating insects more efficiently –
meaning the same number of insects can
pollinate more flowers per day – and this
will help us to grow more food. "I love
the fact I get to do research with both
plants and bees – two of my favorite
things. While these experiments are quite
simple to do, it's amazing to think they
could have such a profound impact on the
crops we'll be using to feed ourselves
in the future."
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"In the past crops have been bred for
things like disease resistance and
shelf-life or yield, with no regard for
features which are attractive to
pollinators. But in the context of a
rising world population and global
pollinator decline, work like we're doing
here at Plant Sciences is becoming more
important. If we can breed crop plants
which are more attractive to insects and
which are easier for them to use, then
we'll be another step along the road to
being able to feed everyone
in the years to come."
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