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Thread: Second trial replicating CCD with neonicotinoids.

  1. #91
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    Quote Originally Posted by Jon View Post
    Working out how pesticides damage bees is based on field studies which look at field realistic doses of the toxins involved.
    This study tipped way over field realistic doses of pesticide into cells containing larvae and noted some damage and developmental aberrations.
    Anyone really surprised?
    This is a totally unnatural situation and like several previous studies only manages to demonstrate that insecticide is toxic to insects and insect larvae especially at high dosage.
    Poor design. Poor study.

    The best bit was where it mentioned queens spawning. Wish I had one of those in my pond.
    PLOSone is a nice journal so I'm surprised at some of the assumptions made in this paper and some of the statements in the introduction about the gaucho incident....it contains many maybes and could haves.

    This was of interest: "The relatively high residue of imidacloprid was observed in the honeycomb and propolis of depopulated beehives [42], indicating that the insecticide could be accumulated in these materials, resulting in the larvae of the colonies being continuously exposed to the contamination before the hives were depopulated."
    It could well be that it accumulates but although I am only a first season beekeeper I dont recall seeing many of the larvae in my hive eating the wax. In fact this lipophilic property was one of the big selling points of apistan (tau-fluvalinate) in that it would keep out of the honey and stay in wax away from harm. Pesticide from farmers = bad but pesticide from beekeepers = good ??? Seems to be flawed reasoning.

    I have to say that the difference between 0.04ng and 0.004ng is actually pretty big in terms of insecticide exposure to larvae, especially when ingested. Someone with more knowledge than might be able to answer what is the biochemical mode of action of the hypopharangeal glands of bees ? If foragers feed on nectar then feed this to the developing brood or add it to brood cells could insecticide in the nectar be broken down in the glands and reduce exposure even further ? I would think it could be relatively simple to test the level of pesticide in the brood cell food directly and get an idea what the "field" level dose of pesticide the larvae are actually getting. From there you could then carry out the experiments put forth in this paper with a bit more confidence in the interpretation of results ?

    I've no idea if this particular pesticide has subtle sub-lethal effects on bee larvae and bee behaviour but the lack of significant bee mortality across the UK in areas where bees are exposed, and have been for some time, along with the literature so far (and thats a caveat!) suggest not. In the case of precautionary principle I think that that ship, rightly or wrongly, sailed a long time ago and I would be extremely worried about going back to some of the pesticides that used to be commonplace. In an ideal world pesticides would not be required at all but an ideal world does not have 8 billion mouths to feed.

    I am willing to be convinced if plausible and significant evidence arises but then thats just good science.

    By the way - I hear all the field level dose stuff being banded about - surely thats not hard to find out and then replicate in both acute and accumulative toxicity studies ? This must have been carried out hundereds of times before on a multitude of pesticides across many countries ?

  2. #92
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    ps: Does Australia use OSR with seed coatings ? How do their bees get on in the absence of Varroa but the presence of seed coating pesticides ? Anyone using this big laboratory to test it ?

  3. #93
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    Quote Originally Posted by greengumbo View Post
    ps: Does Australia use OSR with seed coatings ?
    Yes

    How do their bees get on in the absence of Varroa but the presence of seed coating pesticides ? Anyone using this big laboratory to test it ?
    The Americans import most of their package bees from Australia to make up losses.

    EDIT. I got a PM to say the Yanks stopped importing from the US at the start of 2011 due to the risk of novel pathogens originating in asia
    Last edited by Jon; 14-12-2012 at 10:03 PM.

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