One of the major arguments used by the agrochemicals industry
against the independent scientific evidence highlighting the danger of
neonicotinoids to bees, is their claim that independent studies are laboratory
studies, and that such studies represent unrealistic exposure scenarios in comparison with regulatory field studies.
Elsewhere on this website, I refute the
arguments that the agrochemical regulatory field tests are more realistic and
reliable (they are not), that independent lab tests lack value (they absolutely
do have value), and in fact, there are many independent field trials
highlighting the danger of neonicotinoids to bees.
On 30th June 2017, a large field experiment was published in Science.
Study title: Country-specific effects of neonicotinoid pesticides on honey
bees and wild bees
Authors: Woodcock et al., Science 356, 1393–1395 (2017) 30 June 2017
Overall, ability to reproduce was negatively affected, for both wild bees and managed bees. For example, in Hungary, negative effects on honey bees (associated with clothianidin) persisted over winter and resulted in smaller colonies in the following spring (24% declines).
However, the authors note that results were inconsistent across countries. This is of no surprise to me. Growing conditions will vary across countries, along with general species abundance, availability with local forage, and past profile of chemical usage. In one sense, this illustrates the value of laboratory testing as forming part of the overall picture, since they allow conditions of research to be controlled.
Interesting, although not surprising that when oil seed rape is considered a forage crop for managed honey bees, disease in hives is higher. Multiple studies have indicated that neonicotinoids increase vulnerability to disease, through various means.
Indeed, increased susceptibility to disease following exposure to the toxin is a sub-lethal effect Bayer CropScience have openly referred to as the key factor in their (neonic) Premise 200SC product’s efficacy against termites.
One of the biggest criticisms of regulatory testing for agrochemicals is their failure to take account of sub lethal effects on bees. For example, a toxin may not have immediate or rapid (acute) effects (e.g. mortality - death) through exposure to a large dose, but instead, teeny tiny amounts of the chemical (quite within the regulatory limits) can inflict harm on a bee colony or on individual bees, which may not be immediately visible, but slowly ensure the ultimate demise of the colony.
In other words, if parts of a honey bee colony are affected, this will impair the whole colony in its entirety, since the bees behave collectively as a ‘Super-organism’, wherein all individuals play a crucial role to ensure the survival of the whole. A small number of losses are to be expected and natural, but larger, sustained losses or impairment will ultimately harm the colony.
Due to the long life cycle of honey bee colonies, these effects may take months to manifest (note that even Bayer CropScience admit their neonic product Premise 200SC takes about 3 months to kill a termite colony – termites being another Super-organism, so effects are not always immediately visible). It’s no surprise then, that some months after exposure to the poisons, a beekeeper is baffled by the demise of the honey bee colony, when the bees seemed to forage happily on neonic treated fields months before, and with apparently no immediate ill-effects.
With wild bees, we certainly have tremendous cause for concern. No-one is managing them, they have shorter life cycles and smaller or no colonies, and the effects pass largely unscrutinized and below the radar of general awareness among the public.
The authors of the study state:
You can read the study from this link (opens a new window).
It really is high time we moved away from using damaging poisons which harm bees, other pollinators and the environment, and instead worked with nature to produce food.
Because at the end of the day, we never produced food without bees and other pollinators, but we did produce food without neonicotinoids.
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