Neonicotinoids And Disease In Bees And Other Non-Target Invertebrates
Bayer Cropscience market a product for Termites called Premise
200 SC. Previously, I have outlined some
of the ways in which the company’s marketing literature is revealing in its description
of how the neonicotinoid Imidacloprid, works to kill insects, and thus parallels
are drawn between the claims made for effects on termites versus potential effects
This page can be found How do neonicotinoids work?
The following is a continuation of the information, looking
at not only bees, but some other insect species.
Why it matters
Termites are social insects, ant live in colonies even larger than honey bees – as many as a million or
more, and have many behaviours in common with other non-target species.
Bayer CropScience describe ways in which their neonicotinoid kills termite colonies. A wide range of realistic field and lab studies
indicate similar effects on bees and other invertebrates. So how credible is
it for industry to claim these independent field and lab trials on bees are
credible that imidacloprid conveniently kills termites in the ways outlined by Bayer
Cropscience, yet conveniently has no such negative effects on bees and other non-target
I think this uncomfortable question needs to be asked continually of our politicians, regulators, the media and farmers. And if you have not read it already, please see my page about non-target insects and patents for pesticides.
CropScience Marketing & Product Claims And Their Relevance To Bees And Other Invertebrates
Product Claim Premise 200SC (imidacloprid) leaflet:
200 SC is a systemic insecticide which acts as a contact and stomach
poison. When termites come in contact
with this non-repellent product in the treated zone, the stop tunnelling, stop
feeding, grooming and they become disoriented, they will be infected by soil
fungi and die”.
termite are susceptible to disease and fungi found in soil. A principle part of their defence system is
their grooming habits, allows the termites to get rid of the fungal spores
before these spores germinate and cause disease of death. Premise 200SC interferes with this natural
process by lowering defence to nature’s own weaponry.”
These marketing claims confirm that low doses of Imidacloprid hamper the termite’s ability to groom itself, and
this ultimately kills termites, because it increases susceptibility to
pathogenic soil fungi. It also therefore confirms that ‘low doses’ are
ultimately therefore effective at killing – even at the edge of a treated zone).
- Read more about neonicotinoids and grooming in bees (called hygienic
behaviour) as a method of self-defence against diseases and fungi, as well as mites here.
- Although other insects do not suffer from
Varroa attacks, they do nevertheless have their own mites and diseases to
contend with, such as different strains of nosema in bumble bees.
- Countless studies confirm high prevalence of various bee diseases in cases of 'colony collapse disorder' (or CCD).
- The relationship between neonicotinoids and disruption to
grooming in insects and invertbrates, and their resulting vulnerability to disease,
has been noted in published studies such as:
et al, 2012: Imidacloprid Inhibits Behavioral Defences of the Leaf-Cutting Ant
Acromyrmex subterraneus subterraneus (Hymenoptera:Formicidae) (Ants are in the same insect order as bees –
From the Abstract:
ants have evolved a range of defensive strategies which complicate the use of
entomopathogens for their control. One of these behavioural strategies is
self-grooming, which increases when ants detect the presence of fungal conidia
on their integuments. We have previously shown that insecticides, when used at
ultra-low concentrations, can be synergists of entomopathogenic fungi. It is possible that certain insecticides could
modify ant behavior in a way that increases the chances of a fungal infection
From the conclusion:
modification by exposure to low concentrations of insecticide could render
leaf-cutting ants more susceptible to infection by entomopathogenic fungi as
they fail to eliminate the conidia from their integuments, which under normal
circumstances are quickly removed by efficient self-grooming”.
- Santos et al 2006:
Selection of entomopathogenic fungi for use in combination with sub-lethal
doses of imidacloprid: perspectives for the control of the leaf-cutting ant
Atta sexdens rubropilosa Forel (Hymenoptera: Formicidae).
“Insects treated with
10 ppm IMI [Imidacloprid] were observed to have reduced locomotor activity 24 h
after exposure to the insecticide.
The LC50 of IMI was 154.3 ppm. Subsequent
tests were carried out to evaluate the combination of a sub-lethal dose of IMI
(10 ppm) and infection by CG24 (1 · 107 conidia ml–1).
Mortality due to fungal infection
alone was 43.3%. Mortality of insects treated with IMI followed by exposure to
the fungus was 64.3%. These results indicate that IMI significantly increases
the susceptibility of ants to infection by B. bassiana CG24”.
M. Koppenhöfer et al in 2000, Synergism of imidacloprid and entomopathogenic
nematodes against white grubs: the mechanism:
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
"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
insects, from butterflies to flies and beetles, all engage in grooming. In addition to which, insects other than
termites naturally make contact with soil.
Various bees, flies and beetles nest in the soil and of course, insects
will land, rest or drink from puddles on the surface of soil, and hence may,
like termites, have the opportunity to come into contact with pathogenic soil
There Is Evidence Linking Neonicotinoids
With Bee Diseases
number of studies have highlighted relationships between neonicotinoid
pesticides and mortality in bees due to pathogenic nosema:
- Cédric Alaux et al: Interactions between Nosema microspores and a neonicotinoid
weaken honeybees (Apis mellifera) – Published 2009; Environmental Microbiology.
- Cyril Vidau et al: Exposure to Sublethal Doses of Fipronil and Thiacloprid
Highly Increases Mortality of Honeybees Previously Infected by Nosema ceranae -
Published 2011; PLoS ONE
- Jeffery S. Pettis et al: Pesticide exposure in honey bees results in increased
levels of the gut pathogen Nosema – Published 2011; Naturwissenschaften.
The EFSA Panel on Plant
Protection Products - EFSA Journal 2012; 10(5):2668 commented:
“Indeed, it has been shown that low
levels of some pesticides may have synergic actions with diseases such as Nosema. Finding diseases in test
colonies, which were healthy before the experiment, and not finding such
diseases in control colonies, can imply a synergic effect of pesticides and
of Nosema In The UK
In 2008, the UK National Bee Unit has conducted some study into nosema. You can read more about it national bee unit and nosema here.