gavin
27-03-2013, 11:10 PM
Well, you wait awhile for an interesting report on neonicotinoids, and three come along at the same time. Buses must be like neonic reports. This one should set the conspiracy theorists into melt-down. Defra are showing their hand. I wonder what pose the Scottish Government is going to strike?
An assessment of key evidence about Neonicotinoids and bees (http://www.defra.gov.uk/publications/files/pb13937-neonicotinoid-bees-20130326.pdf)
March 2013
Executive summary
Three recent studies in which bees were dosed with neonicotinoids showed sub-lethal
effects on bees [1-3]. The results from these studies contrast with a growing body of
evidence from field studies that has failed to show an effect of neonicotinoids when
bees are allowed to forage naturally in the presence of crops treated with
neonicotinoids [4-8]. The evidence suggests the reason for this difference is over-
dosing of bees in the dosing studies; in all cases there is evidence that the doses of
neonicotinoids presented to bees under laboratory or semi-field conditions were
unrealistically high. The dosing studies therefore represented the extreme case in a
field situation. In the only study in which dose was measured [1] the dose was much
greater than would have ever been experienced in a field situation.
A concentration of 1-5 μg/l of neonicotinoid in nectar appears to be the threshold below
which an effect tends not to be observed [9] and most residue measurements in the
nectar and pollen of treated crops are normally at or below this level [4,6,7,10,11]. In
addition, examination of bee foraging shows that they tend not to feed exclusively on
treated crops [7], thus diluting any effects of neonicotinoids. Consequently, the
evidence of effects of neonicotinoids on bees come from studies [1-3] in which doses
were likely to have been at least 2-10 times above this threshold.
There is a possibility that field studies did not have the statistical power to show effects
but the accumulated evidence across several independent studies suggests that this is
unlikely and, any effects that are present are likely to be small and not biologically
significant. Moreover, oilseed rape (OSR) requires insect pollinators to support its
productivity [12-18]. The fact that OSR treated with neonicotinoids has been a
productive crop for over a decade in the UK is itself evidence that pollinator
populations, including bees, are not being reduced by the presence of neonicotinoids.
Conclusion: While this assessment cannot exclude rare effects of neonicotinoids on
bees in the field, it suggests that effects on bees do not occur under normal
circumstances. This assessment also suggests that laboratory based studies
demonstrating sub-lethal effects on bees from neonicotinoids did not replicate realistic
conditions, but extreme scenarios. Consequently, it supports the view that the risk to
bee populations from neonicotinoids, as they are currently used, is low.
An assessment of key evidence about Neonicotinoids and bees (http://www.defra.gov.uk/publications/files/pb13937-neonicotinoid-bees-20130326.pdf)
March 2013
Executive summary
Three recent studies in which bees were dosed with neonicotinoids showed sub-lethal
effects on bees [1-3]. The results from these studies contrast with a growing body of
evidence from field studies that has failed to show an effect of neonicotinoids when
bees are allowed to forage naturally in the presence of crops treated with
neonicotinoids [4-8]. The evidence suggests the reason for this difference is over-
dosing of bees in the dosing studies; in all cases there is evidence that the doses of
neonicotinoids presented to bees under laboratory or semi-field conditions were
unrealistically high. The dosing studies therefore represented the extreme case in a
field situation. In the only study in which dose was measured [1] the dose was much
greater than would have ever been experienced in a field situation.
A concentration of 1-5 μg/l of neonicotinoid in nectar appears to be the threshold below
which an effect tends not to be observed [9] and most residue measurements in the
nectar and pollen of treated crops are normally at or below this level [4,6,7,10,11]. In
addition, examination of bee foraging shows that they tend not to feed exclusively on
treated crops [7], thus diluting any effects of neonicotinoids. Consequently, the
evidence of effects of neonicotinoids on bees come from studies [1-3] in which doses
were likely to have been at least 2-10 times above this threshold.
There is a possibility that field studies did not have the statistical power to show effects
but the accumulated evidence across several independent studies suggests that this is
unlikely and, any effects that are present are likely to be small and not biologically
significant. Moreover, oilseed rape (OSR) requires insect pollinators to support its
productivity [12-18]. The fact that OSR treated with neonicotinoids has been a
productive crop for over a decade in the UK is itself evidence that pollinator
populations, including bees, are not being reduced by the presence of neonicotinoids.
Conclusion: While this assessment cannot exclude rare effects of neonicotinoids on
bees in the field, it suggests that effects on bees do not occur under normal
circumstances. This assessment also suggests that laboratory based studies
demonstrating sub-lethal effects on bees from neonicotinoids did not replicate realistic
conditions, but extreme scenarios. Consequently, it supports the view that the risk to
bee populations from neonicotinoids, as they are currently used, is low.