compared to current alternatives”.
for example. Scientists exposed
honeybees to the spider venom
molecule at a range of concentrations, ranging from minute doses
to doses so high that they would
never be seen in a field setting.
After completing the research the
team found that the new biopesticide did not pose a significant risk
to honeybee health. In fact, the
spider venom molecule was about
as harmless to honeybees as a nontoxic control substance, Nakasu
said: “The fact it can selectively kill
insect pests, but not bees, was actually surprising”, he went on to say:
“we consider the molecule to be
relatively safe to bees, particularly when
the new biopesticide did
not pose a significant risk
to honeybee health
56
The exact reason why this new
biopesticide is harmless to bees
and toxic to other pests is not completely clear. But it seems to be
related to the spider venom molecule’s effect on ion channels, which
are proteins found in the lining of
all cells. These proteins control the
flow of charged ions in and out of
the cell, and are vital for many
important physiological processes.
It appears that the spider venom
molecule targets and inhibits a
particular type of ion channel in
the cells of the pest insect, causing mortality. This process doesn’t
seem to happen in honeybees and
this may be because they have a
slightly different version of the ion
channel found in pest species.
This different type of ion channel may not be susceptible to
the spider venom molecule,
making honeybees resistant
to the molecule. The lab
group at the University of
Newcastle is currently completing research to confirm
this theory.