Treatments against Varroa mite are increasingly found to be ineffective, and it is often said that the mites may have developed a resistance to the chemical treatments available.
However, a key natural defence for honey bees against Varroa is for the bees to become “hygienic” – this means, the bees are able to groom and remove the mites from larvae and their bodies. In fact, there are currently efforts to breed “Hygienic bees” that are more likely to engage in this crucial grooming behaviour.
Watch how the honey bee deals with the Varroa mite once it has been removed on this video;
But, given the mode of action of neonicotinoids, is it surprising if these insecticides hinder the ability of bees to develop this grooming ability?
Actually, Bayer Cropscience advertises the mechanism by which sub-lethal doses of imidacloprid, one of their neonicotinoids, kills colonies of Termites, which like bees, are social insects. The key is that disoriented social insects stop grooming and thus get infected with natural pathogens. Here is the quote from the Premise 200SC leaflet (download can be slow, and opens new window). Premise 200SC, is a Bayer product for Termites, which like bees, are social insects. The leaflet reads:
“The termites are susceptible to diseases or fungi found in soil. A principle part of their defence mechanism is their grooming habits, which allows the termites to get rid of the fungal spores before these spores germinate and cause disease or death. Premise 200SC interferes with this natural process by lowering defence to nature’s own weaponry.”
"What is Premise 200SC plus Nature?
Low doses of imidacloprid such as the edge of the Treated Zone, disoriented the termites and caused them to cease their natural grooming behaviour. Grooming is important for termites to protect them against pathogenic soil fungi. When termites stop grooming, the naturally occurring fungi in the soil attack and kill the termites. Imidacloprid makes fungi 10,000 times more dangerous to termites. Nature assists imidacloprid in giving unsurpassed control. This control is called Premise 200SC plus Nature."
Could it be, then, that neonicotinoids interfere with grooming behaviour in honey bees, making them more likely to succumb to Varroa mites and the diseases they carry?
As stated, although this leaflet is particularly concerned with termites and not bees, nevertheless, termites, like bees, are social insects.
Imidacloprid is a neonicotinoid, and it is used on farmland, as well as being available for use in gardening and lawn care products. In view of this information, I would like to know whether regulatory approval bodies (such as DEFRA or the CRD in the UK), considered the impact of these pesticides on crucial natural insect behaviours such as these.
Have they even requested data from Bayer Cropscience investigating the impact on grooming behaviour in honey bees? Did Bayer submit such data, and if so, what steps are the regulatory bodies taking to ensure the data is independently scrutinised? Are they requesting visibility of independent data?
Further evidence of the effects of neonicotinoids on grooming behaviour has also been witnessed in beetles, including having an impact on their larvae. This published study, titled Synergism of imidacloprid and entomopathogenic nematodes against white grubs: the mechanism; by Albrecht M. Koppenhöfer et al in 2000, states:
"The major factor responsible for synergistic interactions between [LOW DOSE!] imidacloprid and entomopathogenic nematodes appears to be the general disruption of normal nerve function due to imidacloprid resulting in drastically reduced activity of the grubs. This sluggishness facilitates host attachment of infective juvenile nematodes. Grooming and evasive behavior in response to nematode attack was also reduced in imidacloprid-treated grubs."
"Brushing (legs or mouth parts swept across body)……and chewing ….occurred significantly more often in grubs not treated with imidacloprid in the presence of nematodes and this response was reduced by 42--70% after imidacloprid treatment."
It seems to me that unless it is proven that neonicotinoids do not impair crucial grooming behaviour in honey bees and non-target insects, then this is further justification for a precautionary suspension, in line with the request from Invertebrates charity, Buglife.
It has also been demonstrated that the interaction between the microsporidia Nosema and a neonicotinoid (imidacloprid), significantly weakened honeybees. This study by Alaux et al was published in Environmental Microbiology 2009: Interactions between Nosema microspores and a neonicotinoid weaken honeybees (Apis mellifera)
UPDATE
In a feature in the Independent newspaper, it is reported that in response to the question of whether Bayer had tested for the effects of neonicotinoids on grooming in honey bees, the reply was 'no':
Quote from the newspaper:
"Dr Julian Little, Bayer's UK spokesman, said: "We do a lot of tests of the effects of insecticides on bees, and impairment of grooming has never shown up."
Specific tests to see whether or not bees' grooming ability was impaired by neonicotinoids had not been carried out, he added."
Further information HERE
Bee Poisoning
- Pesticide Companies Must Be Held To Account
"Pesticide firms must be held to account for bee poisoning" was the title of a recent blog post in The Guardian newspaper, written by Alison Benjamin.
"There is an overwhelming body of evidence pointing the finger at the sub-lethal impact of pesticides on bees" - it continues.
During a three day public tribunal organised by Pesticide Action Network (the Permanent People's Tribunal (PPT)), cases are being brought against the big six pesticide companies; Monsanto, Dow, BASF, Bayer, Syngenta and DuPont, which control 74% of the global pesticide market. You can read more here (opens new window). (The trial is about more than bee poisoning incidents, it is also about general crimes against humanity, such as the disaster in Bhopal, India).
Alison concludes the blog: "My opinion, and that of others, is that there is an overwhelming body of evidence pointing the finger at the sub-lethal impact of pesticides on bees, isn't it time that their creators were held to account?"
While we are on the subject, let's just go over a few misunderstandings and inadequacies regarding our regulatory system:
1. Bee poisoning incidents - where are they actually adequately monitored and reported? It seems to me that any sincere effort to do anything meaningful in the area of government body monitoring, is lacking. You can read more about the UK scenario on my page:
Honey Bee Pesticide Poisoning Incidents (opens a new window), where you will see that honey bee poisoning incidents are not properly monitored (and I wonder if the equipment to test for such incidents would be sufficiently sensitive anyway).
In the USA, Tom Theobald quotes similar frustrations with regard to bee poisoning events, and enforcement of correct application by farmers (which in any event, ignores issues such as toxic build up, but anyway....):
"...let’s talk about foliar treatments and the bee hazard statements since they bring the subject up. Enforcement is a sham, an illusion, there is little or no enforcement. Right here in Boulder County we had a spray incident with a non-systemic pesticide, (one of the foliar treatments they are talking about) in 2008 where we took our own samples and the pesticide level was several hundred times the LD50 for honeybees. The EPA is responsible for enforcement, but delegates that authority to the states. It took 5 weeks of constant prodding before the state would come up and take samples and even then the pesticide level was still several times the LD50. The outcome? The applicator was given a slap on the wrist, a $400 fine with no admission of guilt and still complained about it. How many thousands or tens of thousands of dollars were lost by surrounding beekeepers and what damage was done to the environment by this outrageous level of overspraying? It happens all the time and is seldom challenged, and when it is, it gets the same evasion, doublespeak and non-performance you see in this letter. Enforcement? Hardly. And what purpose does the bee hazard warning on labels serve with systemic pesticides. Are we expected to remove our bees from the area for the next 100 years?"
(Note: with the last comment, Tom is referring to the fact that neonicotinoid pesticides like Clothianidin remain in the soil for many years without degrading, and indeed, they can build up with successive applications!).
2. Where do the regulatory procedures adequately take account of pesticide build up, toxic soup effects, plus mobility of the chemicals in soil and water? I can't find any regulatory (authorising) body or monitoring system which does this with any integrity if at all. And so the idea that pesticides are assessed for 'acceptable risk' to the environment prior to marketing authorisations being granted, is an appalling joke.
3. Where does the regulatory system allow for public scrutiny prior to marketing authorisations being granted?
4. Where are the adequate testing procedures for sub-lethal effects of pesticides on bees (i.e. effects that may not immediately kill, but due to impairment of functioning, usually cause harm and death)?
Here is one example of what to me, seems like gross negligence on the part of the regulatory bodies (they cannot plead ignorance in the UK - the issue has been raised with them repeatedly, and they have ignored it):
Bayer Cropscience market a termite killer, whose active ingredient is the neonicotinoid, Imidacloprid. On their leaflet, Bayer outline how a sub-lethal effect (in this case, impairment of grooming) in termites, makes fungi 10,000 times more deadly to these insects. The Bayer leaflet says: "Grooming is important for termites to protect them against pathogenic soil fungi".
....And don't they realise that grooming is important for bees too? Might grooming be important to help bees defend themselves from pathogenic fungi such as nosema? And of course, grooming is an important natural defence against Varroa. You can read more in my page: Varroa Mite And Neonicotinoids.
I wonder......when public servant, Helen Thompson of FERA was investigating "The relevance of sublethal effects in honey bee testing for pesticide risk assessment", and when she worked with Christian Maus of Bayer Cropscience to produce this "paper", did they discuss the Bayer termite killer, and any possible implication for bees? I have put this question to Lord Henley the government minister responsible at the time - the question has thus far been ignored.
You can read more about honey bee poisoning incidents here.
Source - Buzz About Bees
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