The humble bumblebee --
fuzzy, adorable, yet a vital player
in our ecosystem, responsible
for pollinating crops across the country.
But what happens when these critical pollinators
come in contact with widely used pesticides?
Researchers set out to answer this question by
testing the behavioral effects of a popular insecticide
imidacloprid -- on colonies of bumblebees.
They chose bumblebees
due to the size of their colonies
which are much smaller than honeybee colonies,
making it easier to observe individual bees.
To track their behavior,
each bee was outfitted with its own
small, waterproof 2D barcode
that would allow a robotic camera to record
the movement of each bee individually.
The colonies were separated into
different tracking arenas, each consisting
of a nesting area and a foraging area.
The bees were given access to nectar
with varying concentrations of imidacloprid,
similar to what they might ingest out in the wild.
The scientists used a camera mounted on a
custom robotic chassis to periodically check
in on each colony.
Their findings were striking -
within 24 hours, colonies that were
exposed to the pesticide
exhibited a range of behavioral changes.
The bees were lethargic
and had fewer social interactions.
The bees also foraged less
and spread out from the center of the nest
towards the periphery of the colony.
The researchers also wanted to test the insecticides
effects under more realistic conditions,
so they set up 6 colonies outdoors
equipped with thermal sensors.
Each colony was given access to either pure nectar
or nectar containing imidacloprid.
The researchers measured the surface temperature
of the colony, and the air temperature inside
and outside the colony.
They found that colonies that had ingested
the imidacloprid had trouble regulating the
temperature of the nest, especially as
temperatures outside began to dip.
These colonies were also less likely to construct
a protective wax canopy around the developing young
than colonies that had eaten only pure nectar.
These behavioral changes may seem small,
but when combined they can have drastic effects
on the nest as a whole.
Researchers believe that this study highlights the need
for a better understanding of how insecticides and
other agricultural chemicals
can negatively impact ecosystems.
