Commercially Reared Bumble Bs: Risks To Wild Pollinators
The risk of disease transference by commercially reared bumble bees to other bees, was highlighted in a study back in 2010, carried out by the Department of Entomology, The Pennsylvania State University by Singh et al:
“RNA Viruses in Hymenopteran Pollinators: Evidence of Inter-Taxa Virus Transmission via Pollen and Potential Impact on Non-Apis Hymenopteran Species”
The scientists obtained bumblebees that had been commercially reared in order to perform their experiments.
Commercially reared bumble bees that were meant to be disease free, had diseases.....
This study was actually devised to ascertain whether disease can be passed from honey bees to bumblebees via pollen.
Take into account that commercially reared bumblebees are fed pollen actually harvested from honey bee hives.
However, when the scientists examined the bumblebees, they
found that in some cases, they already had some of the viruses under
investigation!
In other words, some of these commercially reared bumblebees that the scientists had acquired, and that were meant to be free of disease for the purpose of the experiment, were actually already contaminated!
Selected quotes from the study are as follows (an explanation of the abbreviations is below), and there is a link to the actual study at the bottom of the page:
- "In our greenhouse study on the
interspecies transmission of viruses between honey bees and bumble bees, we
obtained bumble bee colonies from two different vendors in two different years....
During the first year trials, tests of bees from one vendor revealed that all six bumble bee colonies came already infected with IAPV, while the colonies from the other vendor were IAPV free."
- "In replicate trials the next year, colonies purchased from the previous year's IAPV-free vendor arrived infected with IAPV. Both companies reported that honey bee-collected pollen purchased from honey bee operations in the US and Canada was used in rearing the bumble bees. We surmise that this pollen was contaminated with IAPV and served as the vehicle for viral transmission into these colonies. More than 200 tons of honeybee-collected and preferably freshly-frozen pollen is used annually for bumble bee rearing worldwide [66]. This same concern may also extend over to honey bees, since many beekeepers purchase pollen to feed their bees."
- "In 2008, six commercial greenhouse bumble bee colonies (a queen and approx. 100
workers) were obtained each from two major commercial bumble bee rearing
facilities; Koppert Biological Systems (Romulus, Michigan, US) and Biobest
Biological Systems (Leamington, Ontario, Canada). Three honey bee colonies were
established along with three bumble bee colonies (Bombus impatiens) in each of
four rooms (16′×20′) in a greenhouse, with separate equipment used in each
room."
- All colonies of honey bees and bumble bees were tested for IAPV, DWV, BQCV, SBV, ABPV, CBPV and KBV when introduced into the greenhouse. For each bumble bee colony, five workers were tested upon arrival; for honey bee colonies, 20 workers and 10 egg samples were tested. All bumble bee colonies were found to have DWV and BQCV upon arrival; no KBV, SBV, ABPV or CBPV was detected. The Koppert bumble bees had no IAPV; however, the Biobest bees had the eastern strain of IAPV upon arrival. For the 2008 experiment, we focused only on Koppert bumble bees. The honey bee colonies had DWV, BQCV, and low prevalence of KBV; no IAPV was found in the honey bee colonies."
- "In our greenhouse study on the interspecies
transmission of viruses between honey bees and bumble bees, we obtained bumble
bee colonies from two different vendors in two different years. During the
first year trials, tests of bees from one vendor revealed that all six bumble
bee colonies came already infected with IAPV, while the colonies from the other
vendor were IAPV free. In replicate trials the next year, colonies purchased
from the previous year's IAPV-free vendor arrived infected with IAPV. Both
companies reported that honey bee-collected pollen purchased from honey bee
operations in the US and Canada was used in rearing the bumble bees. We surmise
that this pollen was contaminated with IAPV and served as the vehicle for viral
transmission into these colonies.
More than 200 tons of honeybee-collected and preferably freshly-frozen pollen is used annually for bumble bee rearing worldwide. This same concern may also extend over to honey bees, since many beekeepers purchase pollen to feed their bees.”
Abbreviations:
IAPV = Israeli Acute Paralysis virus
DWV = deformed wing virus
BQCV = Black queen cell virus
SBV = Sacbrood virus
ABPV = Acute bee paralysis virus
CBPV = Chronic bee paralysis virus
KBV = Kashmir bee virus
The whole study can be viewed here
(opens new window).
And yet the study also states that it is possible to treat the pollen (it can
be gamma irradiated without destroying nutritional and physical properties).
Before organisations offer commercially reared bumblebees for sale, shouldn't steps be taken to ensure pollen has been appropriately treated before it is sold and fed to other bees, and used in any breeding programmes?
US
conservation charity, Xerces, raises concerns about commercially reared bumble bees
That diseases could be spread from commercially reared to wild bee species, is a concern also raised by Xerces:
"Between 1992 and 1994, queens of B. occidentalis and B. impatiens were shipped to European rearing facilities, where colonies were produced then shipped back to the U.S. for commercial pollination. Bumble bee expert Robbin Thorp has hypothesized that these bumble bee colonies acquired a disease (probably a virulent strain of the microsporidian Nosema bombi) from a European bee that was in the same rearing facility, the buff-tailed bumble bee (Bombus terrestris). The North American bumble bees would have had no prior resistance to this pathogen. Dr. Thorp hypothesizes that the disease then spread to wild populations of B. occidentalis and B. franklini in the West (from exposure to infected populations of commercially reared B. occidentalis), and B. affinis and B. terricola in the East (from exposure to commercially reared B. impatiens). In the late 1990′s, biologists began to notice that B. affinis, B. occidentalis, B. terricola, and B. franklini were severely declining.”
Why does it take so long for us to learn from mistakes?
The need to reduce risk from disease transmission is sure common sense! It is astonishing that commercial breeders have not themselves taken measures to safeguard against this problem, even without regulation.
Nevertheless, perhaps regulation is required.
In the meantime, those who use commercially reared bumble bees need to take extra stringent measures to ensure they do not escape from poly tunnels into the wild.
In addition, the purchase of bumble bees for domestic use in gardens, should be stopped. Persons who wrongly think they are helping bees by such practice, need to be guided instead to provide pollution-free habitat.
Read more about research into the disease risks posed to wild bees via commercially reared bumblebees commercially reared bumble bees here.
Pssst ... spread the word!
