<html>
<body>
<font size=2>David, A., et al. (2016). "Widespread contamination of
wildflower and bee-collected pollen with complex mixtures of
neonicotinoids and fungicides commonly applied to crops."
<u>Environment International</u> <b>88</b>: 169-178.<br><br>
<dl>
<dd><x-tab> </x-tab>There
is considerable and ongoing debate as to the harm inflicted on bees by
exposure to agricultural pesticides. In part, the lack of consensus
reflects a shortage of information on field-realistic levels of exposure.
Here, we quantify concentrations of neonicotinoid insecticides and
fungicides in the pollen of oilseed rape, and in pollen of wildflowers
growing near arable fields. We then compare this to concentrations of
these pesticides found in pollen collected by honey bees and in pollen
and adult bees sampled from bumble bee colonies placed on arable farms.
We also compared this with levels found in bumble bee colonies placed in
urban areas. Pollen of oilseed rape was heavily contaminated with a broad
range of pesticides, as was the pollen of wildflowers growing nearby.
Consequently, pollen collected by both bee species also contained a wide
range of pesticides, notably including the fungicides carbendazim,
boscalid, flusilazole, metconazole, tebuconazole and trifloxystrobin and
the neonicotinoids thiamethoxam, thiacloprid and imidacloprid. In bumble
bees, the fungicides carbendazim, boscalid, tebuconazole, flusilazole and
metconazole were present at concentrations up to 73 nanogram/gram (ng/g).
It is notable that pollen collected by bumble bees in rural areas
contained high levels of the neonicotinoids thiamethoxam (mean 18 ng/g)
and thiacloprid (mean 2.9 ng/g), along with a range of fungicides, some
of which are known to act synergistically with neonicotinoids. Pesticide
exposure of bumble bee colonies in urban areas was much lower than in
rural areas. Understanding the effects of simultaneous exposure of bees
to complex mixtures of pesticides remains a major challenge.<br><br>
</font>
</dl></body>
</html>