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Honeydew: There have been some concerns that
the sugary sap may contain harmful
Photo: Rowland Janes fast food for to be good at avoiding things that
toxins, however bumblebees tend
are toxic to them and will generally
bumblebees?
avoid flowers that might harm them.
This interesting behaviour has likely
been going on for millennia, so even
By Darryl Cox, Senior Science
and Policy Officer if the secretions do contain toxins,
bumblebees might have already
evolved the ability to tolerate them,
One of our most common enquiries prompted by the warm weather last year as they have with some plants.
this month has been related to some and a relatively mild and wet winter,
peculiar behaviour. Many people have which are ideal conditions for them. One thing that honeydew cannot
got in touch to ask why they are seeing What is really interesting is that many replace however, is pollen, which
bumblebees visiting curled up leaves on of the gardens that people witness this provides the essential protein for
flowerless hedges and trees like beeches behaviour in are full of bee-friendly growing larvae into adult bees. It
and apple trees. flowers, which essentially means is therefore unlikely we will see
Photo: Bumblebee feeding on
These plants have fallen victim to sap- bumblebees are not resorting to bumblebees switching from flower honeydew by Rowland Janes
sucking aphids, the winged adult forms feeding from honeydew due to a lack foraging to aphid farming any time soon.
of which are familiarly known as blackfly of food availability, but are choosing to
or greenfly. These plant-fluid-feeders consume the honeydew over nectar.
happily consume the lifeblood of the Bumblebee colony success is all down
plants and excrete volumes of sugary to energy-economics and bumblebees
liquid waste, known as honeydew. It naturally attempt to collect food as
doesn’t take long for aphid populations efficiently as possible, so it may be that
to explode and as a result there are during these aphid booms there is an
swathes of other animals that gather to easier, larger or more energy-rich fast-
either consume the aphids themselves food on offer in the form of honeydew
or their sugary secretions. The best that bumblebees can take advantage of.
example are ants, which go as far as to
protect aphids from other predators and
essentially farm them for the sweet liquid
they produce.
Bumblebees will also opportunistically
feed on the sugar-rich honeydew, which
provides them with carbohydrates, in a
similar way to nectar. We often receive
at least a couple of reports of this
fascinating behaviour each year, but this
year we have been receiving many more
reports than usual. It seems to be a bit
of a bumper year for aphids, probably
Photo: Bumblebees feeding on
20 honeydew by Susan Haines 21

Photo: Martin Lines, Nature
Friendly Farming Network