[Pil-pc-oceania] FW: Bees and Insecticides

[Cecile]

FYI a contribution to the bee question.
Cheers
Cecile

  _____  

From: Arnold Ward [mailto:arnold1 at chariot.net.au] 
Sent: Wednesday, 25 April 2007 11:12 AM
To: Undisclosed-Recipient:;
Subject: Bees and Insecticides


Greetings:
 
Here is more information on possible causes of bee deaths.
 
With my regards
 
Arnold
 

ISIS Press Release 24/04/07 


Requiem for the Honeybee


Neoniccotinoid insecticides used in seed dressing may be responsible for the
collapse of honeybee colonies  <http://www.i-sis.org.uk/contact.php> Prof.
Joe Cummins


Neonicotinoid insecticides are harmful to the honeybee


There has been a great deal of concern over the decline of the honeybee
across the US, Europe and Australia [1] (The Mystery of
<http://www.i-sis.org.uk/MysteryOfDisappearingHoneybees.php> Disappearing
Honeybees, this series). The United States National Research Council (USNRC)
Committee of the Status of Pollinators in North America report [2] focused
on the impact of parasites, fungi, bacteria and viruses, but did not pay
much attention on the impact of pesticides and genetically modified (GM)
crops, which may have lethal or sub-lethal effects on the bee's behaviour or
resistance to infection. There have been strong responses to the report on
that account. On the other hand, any suggestion that GM crops and pesticides
may be causing the decline of honeybees is met with heated denial from the
proponents.

Certainly, honeybees are declining both in areas where GM crops are widely
grown, and in other areas where GM crops are released in small test plots.
Is there a common thread that links both areas?  Yes there is, the universal
use of systemic pesticide seed dressing in GM crops and conventional crops;
in particular, the widespread application of a relatively new class of
systemic insecticides - the neonicotinoids - that are highly toxic to
insects including bees at very low concentrations. Systemic pesticide seed
dressings protect the newly sprouted seed at a vulnerable time in the
plant's development. Seed dressings include systemic insecticides and
fungicides, which often act synergistically in controlling early seedling
pests. 

The neonicotinoid insecticides include imidacloprid, thiamethoxam,
clothianidin, and several others. Imidacloprid is used extensively in seed
dressing for field and horticultural crops, and particularly for maize,
sunflower and rapeseed (canola). Imidacloprid was detected in soils, plant
tissues and pollen using HPLC coupled to a mass spectrometer. The levels of
the insecticide found in pollen suggested probable delirious effects on
honeybees [3]. For several years since 2000, French and Italian beekeepers
have been noticing that imidacloprid is lethal to bees, and the insecticide
is suspected to be causing the decline of hive populations by affecting the
bee's orientation and ability to return to the hive. 


Confused and disoriented bees


A team of scientist led by the National Institute of Beekeeping in Bologna,
Italy, found that pollen obtained from seeds dressed with imidacloprid
contains significant levels of the insecticide, and suggested that the
polluted pollen was one of the main causes of honeybee colony collapse [4].
Analysis of maize and sunflower crops originating from seeds dressed with
imidacloprid indicated that large amounts of the insecticide will be carried
back to honey bee colonies [5]. Sub-lethal doses of imidacloprid in sucrose
solution affected homing and foraging activity of honeybees. Bees fed with
500 or 1 000 ppb (parts per billion) of the insecticide in sucrose solutions
failed to return to the hive and disappeared altogether, while bees that had
imbibed 100 ppb solutions were delayed for 24 h compared with controls. [6].
Imidacloprid in sucrose solution fed to the bees in the laboratory impaired
their communication for a few hours [7]. Sub-lethal doses of imidacloprid in
laboratory and field experiment decreased flight activity and olfactory
discrimination, and olfactory learning performance was impaired [8]..

Bayer corporation scientists reported that neither honeybees exposed to
imidacloprid in sunflower seeds dressed with the insecticide [9] nor maize
seeds dressed with the insecticide or released from the seeds during
planting [10] were detrimental to honeybees. The Bayer studies did not deal
with sub-lethal behaviour of intoxicated bees. An independent study found
that imidacloprid was released to the environment from treated maize seeds
during seed planting [11]. Bayer eco-toxicologists directed harsh criticisms
at reports showing lethal or sub-lethal toxic effects of imidicloprid seed
dressing and concluded that imidacloprid does not pose any significant risk
to honeybees in the field [12], without, however, disproving the findings.
It is simply yet another case of the anti-precaution principle being applied
[13] (Use and Abuse of the  <http://www.i-sis.org.uk/prec.php> Precautionary
Principle, ISIS News 6)

Turning to GM crops such as maize, canola, cotton and soybean it is clear
that all of these GM crops, with or without Bt genes, use seeds most of
which are coated with neonicotinoid pesticides highly toxic to honey bees.
For example, Herculex maize with Bt genes to control rootworm, like
Yieldgard corn borer resistant maize, is planted with seeds dressed with a
neonicotinoid insecticide and a fungicide. Furthermore, the GM planting
requires setting aside plots of non-GM maize making up 20 percent of the
planted area as a "refuge" to discourage the evolution of resistant insects.
But the "refuge" is sprayed with neonicotinoid pesticide to protect its
yield [14], and is more like a death camp for insects. Monsanto's US Patent
6,660,690 provides for coating GM seeds with chemical pesticides [15].


Toxicology known


The toxicology of neonicotinoid insecticides is well known. The insecticides
are inhibitors of acetycholine receptors (i.e., they are nerve poisons).
They have low toxicity for mammals, birds and fish, and are used to control
fleas on dogs and cats [16]. The nicotinic acetylcholine receptor gene
family of the honeybee has been studied; it has 11 subunit members, a larger
number than the fruit fly or mosquito. The genes for the subunits employ
alternatively spliced transcripts to increase receptor diversity, and the
messenger RNAs are edited to replace specific A bases with I bases.
Information on the receptor should allow for development of insecticides
that are not harmful to bees [17].

In conclusion, the US NRC Committee did not deal with the heated debate over
neonicotinoid pesticides and honeybee decline. Instead, that it seemed to
suffer from tunnel vision and to be overcautious about matters that threaten
large corporations. 

We urgently need a thoroughly independent committee to consider the full
range of factors that may be contributing to the decline of bees, including
pesticides, GM crops and electronic devices, before the bees become extinct.


References


1. Ho MW and Cummins J. The mystery of disappearing honeybees. Science in
Society 34 <http://www.i-sis.org.uk/isisnews/sis34.php>  (in press)

2. Committee on the Status of Pollinators in North America American National
Research Council   Status of Pollinators in North America  2006
ISBN:978-0-309-10289-6

3. Bonmatin JM, Moineau I, Charvet R, Fleche C, Colin ME and Bengsch ER.
A LC/APCI-MS/MS method for analysis of imidacloprid in soils, in plants, and
in pollens. Anal Chem. 2003 May 1;75(9):2027-33.

4. Bonmatin JM, Marchand PA, Charvet R, Moineau I, Bengsch ER and Colin ME.
Quantification of imidacloprid uptake in maize crops. J Agric Food Chem.
2005 Jun 29;53(13):5336-41.        

5. Rortaisa A, Arnolda G, Halmbm M and Touffet-Briensb F. Modes of honeybees
exposure to systemic insecticides: estimated amounts of contaminated pollen
and nectar consumed by different categories of bees Apidologie 2005, 36 ,
71-83 

6. Bortolotti L, Monanari R, Marcelino J and Porrini P. Effects of
sub-lethal imidacloprid doses on the homing rate and foraging activity of
honey bees. Bulletin of Insectology 2003, 56 (1),: 63-67

7. Medrzycki P, Monntanari L, Bortolotti L, Sabatinin S and Maini S. Effects
of imidacloprid administered in sub-lethal doses on honey bee behaviour.
Laboratory tests. Bulletin of Insectology 2003, 56 (1): 59-62

8. Thompson H. Behavior effects of pesticides in bees-their potential for
use in risk assessmernt. Ecotoxicology 2003,12,317-30

9. Schmuck R, Schoning R, Stork A and Schramel O. Risk posed to honeybees
(Apis mellifera L, Hymenoptera) by an imidacloprid seed dressing of
sunflowers. Pest Manag Sci. 2001, 57(3), 225-38.

10.  Schnier H, Wenig G, Laubert F, Simon V and Schmuck R. Honey bee safety
of imidacloprid corn seed treatment Bulletin of Insectology 2003, 56 (1),
73-75.

11.  Greatti M, Sabattini A, Barbatiini R, Rossi S and Stravisi A. Risk of
environmental contamination by the active ingredient imidacloprid used for
corn seed dressing. Preliminary results. Bulletin of Insectology 2003, 56
(1), 69-72.

12.  Maus C, Cure G and Schmuck R. Safety of imidacloprid seed dressings to
honey bees:

a comprehensive overview and compilation of the current state of knowledge.
Bulletin of Insectology 2003, 56 (1), 51-57.

13.  AgriGold Hybrids  Insect Resistance management  2007
http://www.agrigold.com/index.cfm?pageId=35

14.  Saunders PT. Use and abuse of the precautionary principle. ISIS
submission to US Advisory Committee on International Economic Policy
Biotech. Working Group 13 July, 2000, also ISIS News 6, September 2000,
http://www.i-sis.org.uk/prec.php

15.  Asrar J and Kohn F. Seed treatment with combinations of insecticides.
2003 United States Patent 6,660,690.

16.   Tomizawa M and  Casida JE. Neonicotinoid insecticide toxicology:
mechanisms of selective action. Annu Rev Pharmacol Toxicol. 2005; 45, 247-68

17.  Jones AK, Raymond-Delpech V, Thany SH, Gauthier M and Sattelle DB.
The nicotinic acetylcholine receptor gene family of the honey bee, Apis
mellifera. Genome Res. 2006, 16(11), 1422-30.

 

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