Fungicides are among the top contaminants of honey bee hives and can interfere with the bees’ ability to metabolize other pesticides. Credit: L. Brian Stauffer

 

When given the choice, honey bee foragers prefer to collect sugar syrup laced with the fungicide chlorothalonil over sugar syrup alone, researchers report in the journal Scientific Reports.

The puzzling finding comes on the heels of other studies linking fungicides to declines in honey bee and wild bee populations. One recent study, for example, found parallels between the use of chlorothalonil and the presence of Nosema bombi, a fungal parasite, in bumble bees. Greater chlorothalonil use also was linked to range contractions in four declining bumble bee species.

Other research has shown that European honey bees have a very limited repertoire of detoxifying enzymes and that exposure to one potentially toxic compound – including fungicides – can interfere with their ability to metabolize others.

“People assume that fungicides affect only fungi,” said University of Illinois entomology professor and department head May Berenbaum, who led the new research with postdoctoral researcher Ling-Hsiu Liao. “But fungi are much more closely related to animals than they are to plants. And toxins that disrupt physiological processes in fungi can also potentially affect them in animals, including insects.”

Some scientists have argued that bees may be less susceptible to agricultural chemicals than laboratory studies suggest because the bees might detect potentially toxic chemicals in the environment and avoid them. But a 2015 study found that European honey bees and at least one species of bumble bee actually prefer food laced with neonicotinoid pesticides.

To test whether foraging honey bees showed a preference for other chemicals they are likely to encounter in the wild, Liao set up two feeding stations in a large enclosure. Foraging honey bees could fly freely from one feeder to the other, choosing to collect either sugar syrup laced with a test chemical or sugar syrup mixed with a solvent as the control. Over the course of the study, she tested honey bee responses to nine naturally occurring chemicals, three fungicides and two herbicides at various concentrations.

The trials revealed that honey bees prefer the naturally occurring chemical quercetin over controls at all concentrations tested.

Entomology professor May Berenbaum, left, and postdoctoral researcher Ling-Hsiu Liao found that honey bees have a slight preference for food laced with the fungicide chlorothalonil at certain concentrations. Credit: L. Brian Stauffer

“That makes sense, because everything the honey bees eat has quercetin in it,” Berenbaum said. “There’s quercetin in nectar, there’s quercetin in pollen. Quercetin is in honey and beebread, and it’s a reliable cue that bees use to recognize food.”

To the researchers’ surprise, the bees also preferred sugar syrup laced with glyphosate – the active ingredient in Monsanto’s Roundup herbicide – at 10 parts per billion, but not at higher concentrations. And while the bees actively avoided syrup containing the fungicide prochloraz, they showed a mild preference for sugar syrup laced with chlorothalonil at 0.5 and 50 parts per billion, but not at 500 ppb.

“The bees are not only not avoiding this fungicide, they’re consuming more of it at certain concentrations,” Berenbaum said.
Fungicides are among the most prevalent contaminants of honey bee hives, and it is likely the bees themselves are bringing these pesticides into the colony through their food-collecting activities. While perplexing, bees’ preferences for some potentially toxic chemicals may be the result of their distinct evolutionary history, Berenbaum said.

“Honey bee foragers are gleaners,” she said. “They’re active from early spring until late fall, and no single floral source exists for them for that whole season. If they don’t have a drive to search out something new, that’s going to seriously compromise their ability to find the succession of flowers they need. Unnatural chemicals might be a signal for a new food.”

The new findings are worrisome in light of research showing that exposure to fungicides interferes with honey bees’ ability to metabolize the acaricides used by beekeepers to kill the parasitic varroa mites that infest their hives, the researchers said.

“The dose determines the poison,” Berenbaum said. “If your ability to metabolize poisons is compromised, then a therapeutic dose can become a toxic dose. And that seems to be what happens when honey bees encounter multiple pesticides.”

More information: Ling-Hsiu Liao et al, Behavioral responses of honey bees (Apis mellifera) to natural and synthetic xenobiotics in food, Scientific Reports (2017). DOI: 10.1038/s41598-017-15066-5

Tallow Under Threat:
Southern States May Lose
Major Nectar Source
Courtesy of Louisiana Beekeepers Association
To Whom It May Concern,

On behalf of the Louisiana Beekeepers Association, all beekeepers and pollinator supporters statewide and nationally, we strongly urge you to oppose any action to introduce the non-native flea beetle, Bikasha collaris, as a biological control for the Chinese tallow tree (Triadica sebifera). The introduction of this beetle and control of Chinese tallow would result in the loss of a major forage source for honey bees and other pollinator species. This would directly affect these important pollinators, exacerbate the already disastrous Colony Collapse Disorder (CCD), and lead to very serious economic impacts for beekeepers and farmers on a national scale.

The current and future status of honey bees and other pollinating insects has received increasing scientific and public concern in the last decade. Honey bees and beekeeping are now considered an essential part of our overall agricultural efforts, not just for the economic contribution of honey sales, but for their key pollination contributions to one-third of the food that Americans consume (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2701761/). According to economic research from the Cornell University, pollinators contribute 29 billion dollars to the agriculture sector. “More specifically, honeybees pollinated $12.4 billion worth of directly dependent crops and $6.8 billion worth of indirectly dependent crops in 2010.” (http://news.cornell.edu/stories/2012/05/insect-pollinators-contribute-29b-us-farm-income)

The Chinese tallow is now found in 12 states as noted in the BCIP Project Proposal (exhibit A). It provides a major (honey) market value in at least four of these states. Tallow can be found in all 64 parishes in Louisiana and also in 55 counties of Texas. Honey sales in Louisiana contribute over eight million dollars to the state agriculture sector (NASS). In 2016, Texas produced eight million pounds of honey, with a wholesale value of $11.5 million, seven million pounds of which are attributed in part to the Chinese tallow nectar flow. Nationally, honey sales contribute roughly 336 million dollars to the value of US agriculture commodities in 2016 (https://www.nass.usda.gov/Statistics_by_State/Louisiana/Publications/Livestock_Press_Releases/BeeHoney/2017/lahoney17.pdf). Even though this is a significant contribution to our economy, the US still remains the top national importer of foreign honey at 423 million dollars (http://agriexchange.apeda.gov.in/product_profile/Major_Imporing_Countries.aspx?categorycode=0408). The obvious conclusion is that beekeepers and honey producers in the United States need public support to preserve existing pollinator forage and nectar sources, particularly those so valuable as Chinese tallow. Hence the Pollinator Protection Act instituted federally in 2014.

There are over 4 million pounds of honey produced annually in Louisiana (NASS). Commercial beekeepers move thousands of colonies to Louisiana for the main purpose of capitalizing on the abundant forage here and particularly the nectar of the tallow tree. The Chinese tallow is a major nectar contributor to the amount of honey produced in Louisiana. In an article published in the American Bee Journal, Hayes (1979) states “(The Chinese tallow tree)… has become the most successful tree nectar source ever introduced into the United States.” Tallow trees have been around since the founding of the United States. “[Ben Franklin] sent tallow seeds to a farmer friend in Georgia in 1772 to be grown as a cash crop.” (http://blog.chron.com/houstongrows/ 2011/08/did-ben-franklin-bring-invasive-tallow-tree-to-texas/) Tallow trees have truly turned into a cash crop for beekeepers.

Steve Bernard, local commercial beekeeper and owner of Bernard Apiaries Inc., claims that loss of the tallow trees would result in a 1.25 million dollar annual loss for his business. A decrease in tallow population or even worse, the complete eradication of the tallow tree by the flea beetle would greatly damage the commercial beekeeping industry statewide and nationally.

Reiterating, hundreds of thousands of hives are moved through the gulf coast areas during the tallow season. These hives are used specifically in the migratory pollination process and depend on tallow trees for pollen and spring build up. The hives later go to other areas in the country for further honey production and pollination services. This is of greater economic value than the honey produced from tallow trees.

Colony Collapse Disorder has been linked to a number of problems, but notably from the disappearance of critical pollinator habitat. Federal government dollars are being set aside to fund the repopulation of areas for pollinators and to provide protection for existing habitat. In Louisiana and other southern states, the Chinese tallow provides a significant source of nectar as well as pollen. To control or reduce the population of this targeted species, as suggested in the BCIP Project Proposal, would be counter to the Presidential memorandum…“to ensure the sustainability of our food production systems, avoid additional economic impact on the agricultural sector, and protect the health of the environment.” Under “Sec. 3. Increasing and Improving Pollinator Habitat (e) The Departments of Agriculture and the Interior shall… develop best management practices for executive departments and agencies to enhance pollinator habitat on Federal lands.” There are many acres of Federal land that would be directly at risk in Louisiana should this beetle be introduced and not contained and/or non-target plants be affected (exhibit B). As in all biological control agents, there are no guaranteed ways to contain them.

This concern leads to others, such as the success record for introducing related biological species with or without appropriate trials and very careful research protocols. In the case of the purple loosestrife in Massachusetts a biological control was successfully introduced in eliminating this plant, but at the same time the honey crop was eliminated, as well as forage for all pollinators. A more aggressive invasive species, phragmites, replaced the loosestrife, and now, there is no known control of this plant. Another similar story of unsuccessful biological control is the case of the Asian Lady Beetle which continues to be problematic today. Many other failed biological controls can also be cited. Release of the Bikasha collaris into less than very carefully controlled settings could lead to disastrous consequences. The opportunity for the beetle to adapt and reproduce ina new environment is virtually unknown. In Biological Control: Measures of Success (editor G.Gurr, Steve Wratten), the authors report “only around 10 per cent of attempts are successful”and that the success rate has changed little for a century. They also note that “biological control can cause harm, for instance when the released agent attacks a non-target organism of conservation or economic value.”

We certainly recognize the research and claims that invasive Chinese tallow is leading to an economic loss of $300 million over a twenty year period in certain timber and forest regions of this state and others. Some of these industry researchers also believe that introducing the flea beetle could conceivably decrease the amount of chemicals used in that industry and other agricultural sectors to control the encroachment of the tallow tree on cleared land. Yet these industries have alternative methods of control whereas the beekeeping industry does not have an alternative forage source comparable to the Chinese tallow. As of today, the states that would be most affected by the proposed flea beetle gross an annual $76 million in value of production (USDA, 2016), much of which is attributed to the presence of the Chinese tallow. This particular honey is produced in such volumes that it merits its own classification. Tallow honey sales are differentiated from other honey crops harvested and can bring up to $1.60/lb (USDA Honey Report, November 2017) and in some areas of Louisiana over $2/lb. Tallow honey is also used to make unpalatable honeys “table grade” by blending it with other honey to improve flavor. There are other beneficial uses of the Chinese tallow. Studies have shown that the tallow can be a lucrative source for biofuel. The trees are also considered ornamental plants to some locals.

Nectar and pollen from the Chinese tallow are of substantial economic value to commercial beekeepers and the beekeeping industry. Protection of this pollinator habitat needs to be secured. For these reasons, we respectfully urge you to oppose the introduction of the non-native flea beetle for the control of the Chinese tallow tree. Further research and experimentation with such a potentially dangerous biological control species should be restricted, or at the very least, very closely scrutinized and carefully monitored, so as to not lead to irreversible damage to existing Chinese tallow and cause great harm to pollinator populations, the entire beekeeping industry and ultimately the entire agriculture sector.

Sincerely,

Randy Fair
President
Louisiana Beekeepers Association
Chair, Honey Commodity Committee
Louisiana Farm Bureau
Sideliner Beekeeper, Class A
Clear Lake Apiaries … + Associations
Commercial Migratory Beekeeper, Class A
Sunshine Honey Bees

Steve Bernard
P