# In-hive Pesticide Exposure: Assessing risks to migratory honey bees



## JWChesnut (Jul 31, 2013)

*In-hive Pesticide Exposure: Assessing risks to migratory honey bees from in-hive pesticide contamination in the Eastern United States
*
Though just published today, the study data dates to 2007 (which may explain presence of Apistan and other materials).
Full paper download at: http://www.nature.com/articles/srep33207.pdf

Too long, didn't read summary: Watch out for fungicides on Apples










Cite: Traynor, K. S. et al. In-hive Pesticide Exposome: Assessing risks to migratory honey
bees from in-hive pesticide contamination in the Eastern United States. Sci. Rep. 6, 33207; doi: 10.1038/
srep33207 (2016).

Abstract: 
This study measured part of the in-hive pesticide exposure by analyzing residues from live in-hive
bees, stored pollen, and wax in migratory colonies over time and compared exposure to colony health.
We summarized the pesticide burden using three different additive methods: (1) the hazard quotient
(HQ), an estimate of pesticide exposure risk, (2) the total number of pesticide residues, and (3) the
number of relevant residues. Despite being simplistic, these models attempt to summarize potential
risk from multiple contaminations in real-world contexts. Colonies performing pollination services
were subject to increased pesticide exposure compared to honey-production and holding yards. We
found clear links between an increase in the total number of products in wax and colony mortality. In
particular, we found that fungicides with particular modes of action increased disproportionally in wax
within colonies that died. The occurrence of queen events, a significant risk factor for colony health and
productivity, was positively associated with all three proxies of pesticide exposure. While our exposure
summation models do not fully capture the complexities of pesticide exposure, they nonetheless
help elucidate their risks to colony health. Implementing and improving such models can help identify
potential pesticide risks, permitting preventative actions to improve pollinator health.


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## BernhardHeuvel (Mar 13, 2013)

Concerning fungicides:


*The effects of fungicides on the diversity of microbes in stored pollen and the physiological repercussions on worker and queen honey bees*

Gloria DeGrandi-Hoffman, Kirk Anderson, Mark Carroll, Bruce Eckholm, and Diana
Sammataro, Carl Hayden Bee Research Center, USDA-ARS, 2000 East Allen Road, Tucson, AZ
85719
“Honey bee colonies harbor a wide range of microbes, many of which play vital roles in the
preservation and digestion of pollen. Bees store pollen in comb cells and it is there that the pollen is fermented through the action of microbes and converted into bee bread. There are numerous bacteria and fungi present in bee bread that pre-digest the pollen grains and make the nutrients inside more accessible to the bees. The microbes also supply essential nutrients through their metabolic processes. The action of symbiotic microbes might be compromised if they are exposed to pollen contaminated with fungicides. To test this, we collected pollen from colonies in almond orchards during pollination. In this pollen we detected >6000 ppb of Boscalid, 1700 ppb of Pyraclostrobin, >2800 ppb of Propiconazole, and >12500ppb of Iprodione. Bee bread sampled from colonies in the same orchard had >9000 ppb of Boscalid, >2000ppb of Pyraclostrobin, and 7700 ppb of Iprodione. Propiconazole was not detected in the bee bread samples. *From our pilot studies, we found that bee bread made from pollen contaminated with fungicides has a lower diversity of microbes compared with bee bread made from uncontaminated pollen.* In our current work, we are investigating the effects of the reduction in microbial diversity on the ability of bees to process pollen into worker jelly. Whether there are effects on the ability of the queen to lay eggs and generate volatile signals communicating her egg laying activity also is being determined.”

*Drug interactions between miticides and fungicides in honey bees (Apis mellifera)*
Reed M. Johnson, Department of Entomology, University of Nebraska-Lincoln, Lincoln, NE
68583
The ectoparasitic Varroa mite (Varroa destructor) is one of the most serious pests of honey bees today. Beekeepers often suppress Varroa infestations using pesticides applied at therapeutic doses as anti-parasitic drugs. Three commonly used synthetic miticidal drugs – coumaphos (Checkmite+TM), fenpyroximate (HivastanTM) and tau-fluvalinate (ApistanTM) – appear to be tolerated through cytochrome P450 (P450) mediated detoxification in bees. Just as metabolic interactions can occur between drugs in humans, drug interactions can also occur between miticides detoxified by P450s in bees. Simultaneous exposure to multiple miticides is likely to occur given the high levels of miticide contamination reported in beeswax. Bees are also likely to be be exposed to high doses of fungicides applied to bee-pollinated crops. Fungicides are generally considered safe for bees and there are few restrictions on their application during bloom. However, some fungicides may affect bees' ability to tolerate miticides. Chlorothalonil (BravoTM), a common fungicide found in pollen stores and wax, decreases bees' tolerance of mitides. Prochloraz, an inhibitor of cytochrome P450 activity in fungi, increases the toxicity of coumaphos, fenpyroximate, and greatly increased the toxicity of tau-fluvalinate. *Based on these findings it would be prudent for beekeepers to avoid repeated use of P450-interacting miticides and to avoid using these miticides when bees are likely to come into contact with these or other potentially interacting fungicides.*

P2.59 BRADY S. CHRISTENSEN1, TRAVIS J. CROXALL1, JAY A. YODER1, DIANA SAMMATARO2 AND GLORIA DeGRANDI-HOFFMAN2. Wittenberg University1, USDA-ARS, Carl Hayden Honey Bee Research Center2. *Spraying fungicides reduces symbiotic microbes necessary for bee bread production.*

Honey bee (Apis mellifera) development depends on fungal conversion of stored pollen into bee bread that is fed to larval bees. A combination field-mycological study was done surveying 21 hives in orchards representing various levels of fungicide treatment to determine the amount of fungi present and affected in bee bread. All bee bread samples are characterized by a regular mycoflora profile dominated by Aspergillus spp. and Penicillium spp. and to a lesser extent Cladosporium spp. and Rhizopus spp. Minor components were Alternaria spp., Aureobasidium spp., Bipolaris spp., Colletotrichum spp., Fusarium spp., Mucor spp., Paecilomyces spp., Scopulariopsis spp., Stigmella spp. and Trichoderma spp. (mixed composition), presumably reflective of habitat differences. Bee colonies in direct fungicide spraying resulted in an overall decrease of all fungal components, not a select group or single kind of fungus. This decline correlated with a 3-4 fold suppression in conidia production, 16 hours or 68 hours after spraying. Even if not sprayed with fungicide directly, colonies within 3.2km bee flight range of sprayed areas showed similar reductions in fungal loads as observed in bee bread from directly sprayed areas. Surprisingly, this included colonies from an organic orchard. *We conclude that direct and indirect fungicide exposure is disrupting the bee colony fungal community, with implications for death by production of nutritionally-poor food.* Beekeepers report increased incidence of chalkbrood disease after fungicide spraying that we now attribute to the pronounced reduction of Aspergillus spp. and Penicillium spp. that are inhibitory toward bee pathogens.


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