Bt insect protection of crops and honey bees.

First some updates to reposition this blog page in the context of rapidly changing news reports.

This post started as a safety assessment of Bt Crops as a possible factor in honey bee deaths due to colony collapse disorder (CCD).

Bee deaths in largely GM-free Europe had been mentioned in an earlier GMO Pundit post, but some people still question whether Bt crops are the cause of CCD, as it also occurs in the US.

Fortunately a good overview of the whole issue is recently provided by Klaus Ammann at Myth busters.

He includes examples of news stories linking GM crops to bee deaths, plus background discussion showing that mysterious bee deaths are not new, and occur in places where there are few or no GM crops. Another GMO Pundit post made after this current one provides further safety evidence on this issue.

But further very different late breaking stories broke after bees got in the news, provide extra credibility to the argument that GM crops are not affecting bees:

• Are mobile phones wiping out our bees? (see end of this post)
• Warm winters cause damage, reported in Maryland (see end of this post too
  

And now, that the preamble is done, here is the original item of this post:

Should we worry that Bt (GM) crops may be killing bees?

For this we must consider safety assessment:


Safety Assessment of Bt Crops for Adult and Larval Honeybees

- by Eric Sachs, Yong Gao and Jian Duan, Presented March 29, 2007, Public Hearing, Subcommittee on Horticulture and Organic Agriculture, via Agbioview

Summary

--Entomologists have not been able to determine the cause of CCD (colony collapse disorder) in honey bees. While the cause is not yet clear, there is strong evidence that the production of specific insecticidal proteins from the soil bacterium Bacillus thuringiensis (Bt) in crops to control targeted caterpillar pests and beetles does not pose a risk to honeybees.

--There is extensive information on the lack of non-target effects to diverse groups of beneficial insects including honey bees and other pollinators from Bt microbial preparations that contain Bt proteins.

--Bt proteins are ideal for use in organic production and in Bt crops because they bind specifically to receptors on the mid-gut of sensitive caterpillar pests and have no deleterious effect on beneficial/non-target insects under the conditions of use, including predators and parasitoids of targeted caterpillar pests and honeybees.

--Scientists perform extensive honeybee safety assessments on all insect-protected crops, including Bt corn and Bt cotton. The Bt proteins in these crops have been shown to have no adverse effect on the honeybee.

--EPA risk assessments have demonstrated that Bt proteins expressed in Bt crops do not exhibit detrimental effects to non-target organisms in populations exposed to the levels of Bt proteins produced in plant tissues.

--Specific studies involving Cry1Ab provide strong evidence of the safety of MON 810 Bt corn to the honeybee (similar studies have been conducted with other Bt proteins in genetically modified crops).

--The EPA concluded that based on the weight of evidence there are no unreasonable adverse effects of the Cry1Ab protein expressed in MON 810 Bt corn to non-target wildlife or beneficial invertebrates.

Colony Collapse Disorder in Honey Bees

Because honey bees play such a crucial role in agriculture, the recent news that large areas of the U.S. were experiencing a wide-spread sudden loss (or disappearance) of honey bee colonies caused alarm across the country. This phenomenon has been described by honeybee experts as Colony Collapse Disorder (CCD). Groups critical of the widespread adoption of biotech crops in the U.S. and globally have recently begun a campaign alleging that CCD may be caused by crops expressing one or more Bt proteins. Unfortunately, entomologists have not been able to determine the cause of CCD. While the cause is not yet clear, there is strong evidence that the production of specific insecticidal proteins from the soil bacterium Bacillus thuringiensis (Bt) in crops to control targeted caterpillar pests and beetles does not pose a risk to honeybees.

Safety of Commercialized Bt Proteins in Corn and Cotton

There is extensive information on the lack of non-target effects to diverse groups of beneficial insects including honey bees and other pollinators from Bt microbial preparations that contain Bt proteins. The Bt proteins produced in Bt corn and Bt cotton are present in microbial products used in agricultural systems to control targeted pests. Bt proteins are extremely selective and are toxic only to specific pests . A generalized mode of action for Bt proteins includes ingestion of the protein crystals by insects, solubilization of the crystals in the insect midgut and proteolytic processing of the released Bt protein by enzymes, and binding of the partially digested "activated" protein to specific high-affinity receptors on the surface of the midgut epithelium of target insects . Bt proteins are ideal for use in organic production and in Bt crops because they bind specifically to receptors on the mid-gut of sensitive caterpillar pests and have no deleterious effect on beneficial/non-target insects, un

Safety Assessment of Bt Crops

Scientists perform extensive honeybee safety assessments on all insect-protected crops, including Bt corn and Bt cotton. The Bt proteins in these crops have been shown to have no adverse effect on the honeybee. EPA evaluated studies of potential effects on a wide variety of non-target organisms that might be exposed to the Bt protein, e.g., birds, fish, honeybees, ladybugs, parasitic wasps, lacewings, springtails, aquatic invertebrates and earthworms. Such non-target organisms are important to a healthy ecosystem, especially the predatory, parasitic, and pollinating insects . These risk assessments demonstrated that Bt proteins expressed in Bt crops do not exhibit detrimental effects to non-target organisms in populations exposed to the levels of Bt proteins produced in plant tissues.

To illustrate how the different Bt proteins produced in Bt crops are evaluated for safety to the honeybee, two representative studies are described below for the Cry1Ab protein produced in MON 810 Bt corn. These studies with Cry1Ab protein were conducted with the trypsin-resistant core because this is the insecticidally-active portion of the Cry1Ab protein. Specific studies designed to assess the potential for adverse effects to developing larval and adult honeybees are described below.

Honeybee Larva.

The primary route of exposure for honey bee larvae to the Cry1Ab protein is ingestion of pollen collected by foraging adults from genetically modified plants. Therefore, honey bee larvae were exposed to Cry1Ab protein in their natural diet by including a maximum hazard dose (20 parts per million in distilled water mixed with honey) in developing brood cells. This maximum nominal concentration of 20 ppm was approximately 100 times greater than the maximum expected Cry1Ab protein level in MON 810 pollen. In addition to this treatment group, a negative control group was treated with distilled water. Another control group was treated with heat-attenuated (inactivated) Cry1Ab protein (20 ppm), and one set of larvae received no treatment (untreated control). At least 50 bees (1 to 4 days old) were in each replicate, and there were three replicates for each group. The treatments were administered to each larval cell through an electronic micro-applicator, which delivered 5 microliters (?L) of the test diet.

There were no statistically significant (P>0.05) differences in honeybee larval survival to adult emergence among the four treatment groups. The mean adult survival rates after emergence ranged from 91.7% to 96.0% across all groups, including the controls and Cry1Ab-treated groups. This study demonstrates that honeybee larvae were not adversely affected after being exposed to Cry1Ab protein at a concentration of 20 ppm in their diet.

Adult Honeybee.

Adult bees reared in bee hives were immobilized using CO2. The test diet was prepared by mixing the appropriate amount of the insecticidally-active Cry1Ab protein with a honey-water (50-50) syrup to a concentration of 20 parts per million (?g protein/g diet; ppm). The negative control group was fed the same diet with the exception that no Cry1Ab protein was added to the honey-water mixture. A second control group was fed heat-attenuated (inactivated) Cry1Ab protein at the same concentration (20 ppm) as the treatment group. A fourth test system was an empty cage to measure the amount of diet loss due to evaporation. All diets were presented to the bees in a 6 ml shell vial inserted through a cork in the holding cage lid. Three replicates of four test groups of at least 40 adult honeybees were selected and placed in each holding cage. Two observations were made the first day and were made daily for the duration of the 9-day study. At the time of the daily observation, the test diets were replaced with fre

Adult honeybees exposed to the Cry1Ab protein in a honey-water solution for 9 days at a concentration of 20 ppm showed no signs of treatment-related mortality or toxicity. At the end of the testing period, the mortality percentage was calculated for each group. Mortality in the treatment and the negative control groups was 16.20% and 22.28%, respectively. The heat-attenuated control group mortality was 32.59%. Mortality showed a sharp increase in all three groups from days 6 through 9. At the termination of the test, the highest mortality was observed in the group that was fed the heat-attenuated Cry1Ab protein diet, while the lowest mortality was observed in the group that was fed the Cry1Ab protein diet. The mortalities in the treatment group are not considered to be treatment-related because the two control groups showed a higher percentage of mortality over the same time interval. There was no significant statistical difference (P>0.05) in mortality patterns between any of the groups.

The EPA concluded that based on the weight of evidence there are no unreasonable adverse effects of the Cry1Ab protein expressed in MON 810 Bt corn to non-target wildlife or beneficial invertebrates . They reported no measurable deleterious effects were observed in submitted studies of the Cry1Ab protein administered to honey bee larvae, honey bee adults, parasitic wasps, Ladybird beetles, green lacewings, Collembola (springtails), and Daphnia.

---------

1. Wolfersberger et al., 1986; Hofmann et al., 1988a; Hofmann et al., 1988b; Van Rie et al., 1989; Van Rie et al., 1990
2. Dulmage, 1981; Klausner, 1984; Aronson et al., 1986; Whiteley and Schnepf, 1986; MacIntosh et al., 1990
3. Hoffman et al., 1988a, Hoffman et al., 1988b; Van Rie et al., 1989; Van Rie et al., 1990; Wolfersberger et al., 1986 ; English and Slatin, 1992
4. Wolfersberger et al., 1986; Hofmann et al., 1988a; Hofmann et al., 1988b; Van Rie et al., 1989; Van Rie et al., 1990
5. Cantwell et al., 1972; Krieg and Langenbruch, 1981; Flexner et al., 1986; EPA, 1988; Vinson, 1989; and Melin and Cozzi, 1990
6. US EPA. Bt Plant-Pesticides Biopesticides Registration Action Document. http://www.agbios.com/docroot/articles/2000264-A.pdf
7. US EPA. Bt Plant-Incorporated Protectants October 15, 2001 Biopesticides Registration Action Document. http://www.epa.gov/pesticides/biopesticides/pips/bt_brad2/1-overview.pdf

See previous post Bees disease.
and at Reason Magazine The Plight of the Bumblebee

But wait, this just in:

Are mobile phones wiping out our bees?

Scientists claim radiation from handsets are to blame for mysterious 'colony collapse' of bees
By Geoffrey Lean and Harriet Shawcross, The Independent UK
Published: 15 April 2007

It seems like the plot of a particularly far-fetched horror film. But some scientists suggest that our love of the mobile phone could cause massive food shortages, as the world's harvests fail.

They are putting forward the theory that radiation given off by mobile phones and other hi-tech gadgets is a possible answer to one of the more bizarre mysteries ever to happen in the natural world - the abrupt disappearance of the bees that pollinate crops. Late last week, some bee-keepers claimed that the phenomenon - which started in the US, then spread to continental Europe - was beginning to hit Britain as well.

The theory is that radiation from mobile phones interferes with bees' navigation systems, preventing the famously homeloving species from finding their way back to their hives. Improbable as it may seem, there is now evidence to back this up....


The alarm was first sounded last autumn, but has now hit half of all American states. The West Coast is thought to have lost 60 per cent of its commercial bee population, with 70 per cent missing on the East Coast.

CCD has since spread to Germany, Switzerland, Spain, Portugal, Italy and Greece. And last week John Chapple, one of London's biggest bee-keepers, announced that 23 of his 40 hives have been abruptly abandoned.

Other apiarists have recorded losses in Scotland, Wales and north-west England, but the Department of the Environment, Food and Rural Affairs insisted: "There is absolutely no evidence of CCD in the UK."

The implications of the spread are alarming. Most of the world's crops depend on pollination by bees. Albert Einstein once said that if the bees disappeared, "man would have only four years of life left".

No one knows why it is happening. Theories involving mites, pesticides, global warming and GM crops have been proposed, but all have drawbacks.

German research has long shown that bees' behaviour changes near power lines.

Now a limited study at Landau University has found that bees refuse to return to their hives when mobile phones are placed nearby. Dr Jochen Kuhn, who carried it out, said this could provide a "hint" to a possible cause. continued at the Indepedant

Dr George Carlo, who headed a massive study by the US government and mobile phone industry of hazards from mobiles in the Nineties, said: "I am convinced the possibility is real."

Continued at The Independent.

Update number 2. Jun 15 2007

Maryland Bee Die-Offs Caused by Warmer than Normal Early Winter Weather, according a June 13, 2007 Associated Press story which notes that " ... Maryland beekeepers have lost 45 percent of their bees since last year ... An unusually warm November and December likely caused high fatalities in the state's 8,200 bee colonies, said Jerry Fischer, state apiary inspector. In a briefing to the state Agricultural Commission, Fischer said the warm early winter fooled bees into continuing reproduction - called "brood bearing." When temperatures dropped in January, Fischer said, the bees died ..."

Document Title: The title of the June 13, 2007 Associated Press Story is "Weather said to blame for bee die-off"

Organization: Associated Press

Summary: The following information is taken from the AP story:

Susan Hays, whose family runs Hays Apiaries in Frederick County, said weather was her problem in the last year. The warm December days led to brooding, then when the weather turned, the bees would remain sitting on the broods instead of getting food - even if the honey was just inches away.

"They just froze or starved to death," said Hays, who estimated she lost 10 percent to 15 percent of her 2,000 colonies last winter. Her family sends honeybees as far as California, carried by refrigerated trucks, to pollinate almond crops. The apiary also ships bees to mid-Atlantic area fields to pollinate cucumbers, watermelons and apples.

Maryland only has three large commercial beekeepers such as the Hays family. The majority of Maryland's 1,312 registered beekeepers are hobbyists with a colony or two in the backyard, and they're more susceptible to bad weather.

"I had about 80 percent losses over the winter," said Carl Kahkones, owner of 35 hives at South Mountain Apiaries in Boonsboro. Kahkones is a small-scale honey producer and sells to farmers' markets ...

Source: June 13, 2007 AP story on STLToday.com the internet publication of the St Louis Post Dispatch Newspaper.

Web site: The STLToday.com June 13, 2007 story is posted at
http://hosted.ap.org/dynamic/stories/H/HONEYBEE_DIE_OFF?SITE=MOSTP&SECTION=HOME&TEMPLATE=DEFAULT

Contact: Maryland State Apiary Inspector, Jerry Fischer, may be reached at 410 841 5920; e-mail: FischerJE@MdA.State.Md.us


Selected relevant papers on Bt insecticidal protein specificity:

Hofmann C, Vanderbruggen H, Hofte H, Van Rie J, Jansens S, Van Mellaert H.
Specificity of Bacillus thuringiensis delta-endotoxins is correlated with the presence of high-affinity binding sites in the brush border membrane of target insect midguts.
Proc Natl Acad Sci U S A. 1988 Nov;85(21):7844-8.
PMID: 2856194

Van Rie J, Jansens S, Hofte H, Degheele D, Van Mellaert H.
Specificity of Bacillus thuringiensis delta-endotoxins. Importance of specific receptors on the brush border membrane of the mid-gut of target insects.
Eur J Biochem. 1989 Dec 8;186(1-2):239-47.
PMID: 2557209

Garczynski SF, Crim JW, Adang MJ.
Identification of putative insect brush border membrane-binding molecules specific to Bacillus thuringiensis delta-endotoxin by protein blot analysis.
Appl Environ Microbiol. 1991 Oct;57(10):2816-20.
PMID: 1746942

Van Rie J, Jansens S, Hofte H, Degheele D, Van Mellaert H.
Receptors on the brush border membrane of the insect midgut as determinants of the specificity of Bacillus thuringiensis delta-endotoxins.
Appl Environ Microbiol. 1990 May;56(5):1378-85.
PMID: 2339890

Aranda E, Sanchez J, Peferoen M, Guereca L, Bravo A.
Interactions of Bacillus thuringiensis crystal proteins with the midgut epithelial cells of Spodoptera frugiperda (Lepidoptera: Noctuidae).
J Invertebr Pathol. 1996 Nov;68(3):203-12.
PMID: 8931361

Wolfersberger, M.G. Hofmann, C. Luthy, P.
Interaction of Bacillus thuringiensis delta-endotoxin with membrane vesicles isolated from Lepidopteran larval midgut.
Zentralblatt fur Bakteriologie, Mikrobiologie und Hygiene : 1 : Abt. : Supplemente. Zentralbl Bakteriol Mikrobiol Hyg 1 Abt Suppl 1986. (15)p. 237-238.

Update number 3.

A biologist visitor to this site provides further context. CCD may be good for bees!.


Update number 4. 21st July 2007

Asian Parasite Killing Western Bees - Scientist
Story by Julia Hayley

Story Date: 19/7/2007

MADRID - A parasite common in Asian bees has spread to Europe and the Americas and is behind the mass disappearance of honeybees in many countries, says a Spanish scientist who has been studying the phenomenon for years.

The culprit is a microscopic parasite called nosema ceranae said Mariano Higes, who leads a team of researchers at a government-funded apiculture centre in Guadalajara, the province east of Madrid that is the heartland of Spain's honey industry...

"We started in 2000 with the hypothesis that it was pesticides, but soon ruled it out," he told Reuters in an interview on Wednesday.

...Then he decided to sequence the parasite's DNA and discovered it was an Asian variant, nosema ceranae. Asian honeybees are less vulnerable to it, but it can kill European bees in a matter of days in laboratory conditions...



Update number 5. 21st July 2007 (using the classical even as segue)

Bees Dying: Is It a Crisis or a Phase?

By ANDREW C. REVKIN NY Times

Published: July 17, 2007


...An action plan released Friday by the Department of Agriculture used the phrase “CCD crisis” to describe the recent die-offs, even as it said it was “uncertain whether CCD is a new phenomenon” and described similar die-offs as long ago as 1898...

...What some scientists say is missing from the debate is historical context. “Every time there are these disappearances, the ills of the moment tend to be held accountable,” said May Berenbaum, who heads the entomology department at the University of Illinois Urbana-Champaign and led a National Academy of Sciences review of the status of North American bees and other pollinators that was published last year.

“In the ’60s it was synthetic organic insecticides,” Dr. Berenbaum said. “In the ’70s it was Africanized bee genes. In the 19th century, there is a wonderful report about this resulting from a lack of moral fiber. Weak character was why they weren’t returning to the hives.”...

Michael Burgett, a professor emeritus of entomology at Oregon State University, said the big honeybee losses in some regions could simply reflect unremarkable spikes above a common level of mortality of more than 20 percent in recent decades.

“In the late 1970s we had another scare similar to this,” Dr. Burgett said. “They called it ‘disappearing disease’ at the time. But we never found a specific cause for it, we continued to improve our bee management programs and ‘disappearing disease’ disappeared.”


Update with more links
Notes from PRRI
http://pubresreg.org/index.php?option=com_smf&Itemid=27&topic=4.0


There’s a number of different hypothesis as the cause of the CCD.
A Podcast for the public, from Pennsylvania State University http://podcasts.psu.edu/node/265

CCD has happened before but nobody has ever figured out why, see: http://www.orsba.org/htdocs/download/Dtew.htm

In France, the use of Imidacloprid was blamed for the cause of CCD and was therefore banned. http://en.wikipedia.org/wiki/Imidacloprid_effects_on_bee_population

We are not sure if it’s still used in the US some insects might have developed a resistance to this pesticide.
http://www.msstate.edu/entomology/v8n2/art06.html

A general overview can also be found on wikipedia: http://en.wikipedia.org/wiki/Imidacloprid_effects_on_bee_population#column-one#column-one