A Common Honey Bee Disease is Spread Through Flowers

PHYS.ORG By James Cook University August 7, 2019

Australian native stingless bees. Credit: Dr Peter Yeeles

Australian native stingless bees. Credit: Dr Peter Yeeles

James Cook University scientists have discovered a common honey bee disease can be deadly to native Australian wild bees and can be transmitted by flowers—the first time this link has been made.

JCU's Associate Professor Lori Lach oversaw the study investigating the susceptibility of Australian stingless or "sugar bag" bees to Nosema ceranae—a parasite that causes European honey bees to become less active, develop an increase in appetite, and die prematurely.

"Pathogen spillover from bees kept by bee keepers to wild bee populations is increasingly considered as a possible cause of wild pollinator decline. Spillover has been frequently documented, but not much is known about the pathogen's virulence in wild bees or how long pathogens can survive on a flower," said Terence Purkiss, the honors student who conducted the study.

The scientists found that just over two thirds of the wild bees exposed to the disease caught it, and those that did died at nearly three times the rate of those without it. Most European beehives have been found to contain the disease to some extent.

The scientists also found that flowers can transmit the disease.

"About two thirds of the flowers exposed to infected European honey bees were found to be carrying Nosema ceranae spores. In every case, at least one stingless bee that foraged on the flowers contracted the pathogen. What this means is that wild bees can be infected with the disease by sharing a flower with an infected European bee ," said Dr. Lach.

Five out of the six stingless bee hives the researchers monitored over five months tested positive for the pathogen at least once.

Dr. Lach said species' geographic distributions are changing rapidly due to habitat loss, climate change, and through new species being introduced by humans.

"This leads to novel combinations of interacting species that share no evolutionary history. Introduced species may bring with them their pathogens and parasites and provide an opportunity for these to spread to new species," Dr. Lach said.

Dr. Lach said more work had to be done outside the laboratory setting and within different seasons to get a clearer picture of how dangerous the pathogen is to wild bees.

"We know that new hosts will not have had the opportunity to develop defenses against new pathogens and may be particularly susceptible. For example, human immunodeficiency virus and severe acute respiratory syndrome jumped from chimpanzees and bats, respectively, to humans and have resulted in millions of deaths," she said.

Dr. Lach said it was the first study to find a spillover of the pathogen from European bees to Australia's stingless bees.

"Reducing risk of pathogen transmission from managed to wild bees presents multiple challenges and must involve the beekeeping community for any real change to occur. Development of rapid effective diagnostic tools and reliable means of preventing and treating infection will be important advances too," she said.

The work was published today in the Proceedings of the Royal Society B.


Accidental Discovery Could Save Bees From Their Greatest Threat

Real Clear Science     By Ross Pomeroy     January 15, 2018

Agricultural Research ServiceGerman scientists primarily based out of the University of Hohenheim have stumbled upon a simple solution that could deal a blow to honeybees' greatest threat. They've found that a tiny dose of the compound lithium chloride kills Varroa destructor mites without harming bees.

The scientists detailed their incredible findings in the January 12th publication of Scientific Reports.

V. destructor, more commonly known as the Varroa mite, is a scourge of honeybees across the globe. Upon infiltrating a colony, the mites latch on to bees, sucking their hemolymph (essentially blood) and spreading the diseases they carry. According to the USDA, 42 percent of commercial hives in the U.S. were infested in summer 2017, and 40 percent of beekeepers said the parasite seriously harmed their colonies. By comparison, only 13 percent reported harm from pesticides.

Chemical compounds exist to combat the parasites but they are outdated and growing increasingly ineffective, the researchers write, adding that no new active compounds have been registered in the last 25 years.

The dearth of options prompted scientists at The Hebrew University of Jerusalem to experiment with a technique called RNA interference. In their study, they fed bees double-stranded RNA via a sugar solution to knockout vital genes in Varroamites. The mites ingested the lethal RNA via bees' hemolymph and subsequently died.

Inspired by those results, the German researchers sought to replicate them by repeating the experiment with slightly tweaked methods. Indeed, mites infesting bees that were fed sugar water with the designed RNA rapidly died, but so did mites in a control group given another RNA that should have been ineffective. The astonishing results prompted the researchers to suspect that the lithium chlorideused to produce the RNA – and thus present in the sugar water – was actually killing the parasites. A battery of subsequent examinations confirmed their hypothesis.

The scientists then carried out numerous experiments testing lithium chloride against Varroa mites, including ones that approximated field studies. They found that feeding honeybees minuscule amounts of lithium chloride (at a concentration of no more than 25 millimolar) over 24 to 72 hours wiped out 90 to 100 percent of Varroa mites without significantly increasing bee mortality. (Below: The figure shows the surviving proportion of bees and mites fed lithium chloride compared to those not fed lithium chloride.) Ziegelmann et al. / Scientific Reports

According to the researchers, lithium chloride could be put to use very quickly as it is easily applied via feeding, will not accumulate in beeswax, has a low toxicity for mammals, and is reasonably priced. However, wider studies on free-flying colonies testing long-term side effects are required first, as well as analyses of potential residues in honey.

Francis Ratnieks, a Professor of Apiculture at the University of Sussex, expressed skepticism about the new finding.

"We can kill 97% of the Varroa in a brood less hive with a single application of oxalic acid, which takes five minutes to apply and is already registered and being used by beekeepers," he told RCScience via email. "I think it will be difficult in practice to apply lithium salts to colonies to kill varroa and get the same level of control... There are also the wider issues of registration and potential contamination of the honey with a product that would not normally be there."

It should be noted that studies have shown oxalic acid to be inconsistent at managing mites during the summer months as well as in colonies with capped broods

Regardless, the Hohenheim researchers are pressing forward. They're already speaking with companies to get a lithium chloride treatment refined, approved, and in the hands of beekeepers.

"Lithium chloride has potential as an effective and easy-to-apply treatment for artificial and natural swarms and particularly for the huge number of package bees used for pollination in the United States," they conclude.

Source: Bettina Ziegelmann, Elisabeth Abele, Stefan Hannus, Michaela Beitzinger, Stefan Berg & Peter Rosenkranz. "Lithium chloride effectively kills the honey bee parasite Varroa destructor by a systemic mode of action." Scientific Reports 8, Article number: 683 (2018) doi:10.1038/s41598-017-19137-5

*Article updated 1/15 to include Professor Ratnieks' statement and to include information about oxalic acid.

*An earlier version of this article mistakenly reported that the researchers are based out of the University of Hoffenheim. They are from the University of Hohenheim.


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Bees Rigged with RFID Trackers Show Consequences Of Parasites on Pollen Production

Clapway   By Chris   July 15, 2015

Whether they like it or not, bees are the center of attention in the world of scientific studies. This be may be due in part to fact that so many earthly ecosystems depend on their pollination to thrive, or because bee behavior is simply fascinating. Either way, this focus has led researchers to place trackers on honeybees in hives. The results reveal that some of these bees have actually completely lost their ability to pollinate, leading experts to panic about the future of bees and the ecosystems which depend so heavily on them.


The overworked honeybees just won’t get to work, it seems. According to the research executed by Dr. Lori Lach of James Cook University, those bees infected with the parasite Nosema Apis sharply decrease their pollination. This has devastating effects if the parasites become or have become widespread.

According to Dr. Lach’s research, “our finding that bees inoculated with a low dose of N. ap is carried less pollen on their body than non-inoculated bees is...

Read more at Clapway: http://clapway.com/2015/07/15/bees-rigged-with-rfid-trackers-show-consequences-of-parasites-on-bee-pollen-production-213/#ixzz3gSZfQxma