Fungicides Reduce Symbiotic Fungi in Bee Bread and the Beneficial Fungi in Colonies

Yoder, Jay A.; Heydinger, Derrick J.; Hedges, Brian Z.; Sammataro, Diana; Finley, Jennifer; DeGrandi-Hoffman, Gloria; Croxall, Travis J.; Christensen, Brady S.

doi:10.1201/b11318-17

Cited by 5 publications

(3 citation statements)

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“…was identified in bee bread and the nurse honeybee midgut as disease-preventing fungi [ 51 ]. Recently, lower numbers of Rhizopus have been reported to be present in honeybee bread [ 50 ] and in stingless bee Trigona collina collection [ 62 ]. There have been many cases where bees collect fungal spores in place of pollen for unknown reasons [ 63 , 64 ].…”

Section: Discussionmentioning

confidence: 99%

“…has been detected in honeybee bread, crop, midgut, and prepupae [ 47 , 48 ]. Some studies have defined it as a pollen provision contamination; it can spoil bee bread in the right conditions, resulting in a shortage of food supply and a population decline [ 49 ], while other studies considered it a natural defense against the pathogenic fungal disease of chalkbrood via microbe-microbe competition or by producing growth-inhibitory substances, but this is only speculation [ 50 , 51 ]. Rhizopus was found to be a primary cause of provision spoilage for some soil-nesting bees; Rhizopus stolonifer was isolated from the dead brood of the alkali bee and was considered to be the cause of death [ 48 ].…”

Section: Introductionmentioning

confidence: 99%

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A New Isolated Fungus and Its Pathogenicity for Apis mellifera Brood in China

Aynalem,

Meng,

Getachew

et al. 2024

Microorganisms

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In this article, we report the pathogenicity of a new strain of fungus, Rhizopus oryzae to honeybee larvae, isolated from the chalkbrood-diseased mummies of honeybee larvae and pupae collected from apiaries in China. Based on morphological observation and internal transcribed spacer (ITS) region analyses, the isolated pathogenic fungus was identified as R. oryzae. Koch’s postulates were performed to determine the cause-and-effect pathogenicity of this isolate fungus. The in vitro pathogenicity of this virulent fungus in honeybees was tested by artificially inoculating worker larvae in the lab. The pathogenicity of this new fungus for honeybee larvae was both conidial-concentration and exposure-time dependent; its highly infectious and virulent effect against the larvae was observed at 1 × 105 conidia/larva in vitro after 96 h of challenge. Using probit regression analysis, the LT50 value against the larvae was 26.8 h at a conidial concentration of 1 × 105 conidia/larva, and the LC50 was 6.2 × 103 conidia/larva. These results indicate that the new isolate of R. oryzae has considerable pathogenicity in honeybee larvae. Additionally, this report suggests that pathogenic phytofungi may harm their associated pollinators. We recommend further research to quantify the levels, mechanisms, and pathways of the pathogenicity of this novel isolated pathogen for honeybee larvae at the colony level.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A New Isolated Fungus and Its Pathogenicity for Apis mellifera Brood in China

Aynalem,

Meng,

Getachew

et al. 2024

Microorganisms

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“…Despite expectations of selectivity between fungi and animals, fungicides can have adverse effects on honeybees at the colony level, including malnutrition, poor brood-rearing, queen loss, reductions in beneficial fungi, increased titres of viral and microsporidial pathogens, and impaired foraging activities [10][11][12][13][14][15][16][17][18][19]. One such mixture routinely used in almond production is Pristine ® , a formulated fungicide that combines boscalid with pyraclostrobin, a strobilurin fungicide that also targets energy production pathways.…”

Section: Introductionmentioning

confidence: 99%

Fungicide suppression of flight performance in the honeybee ( Apis mellifera ) and its amelioration by quercetin

et al. 2019

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As a managed agricultural pollinator, the western honeybee Apis mellifera frequently encounters agrochemicals as contaminants of nectar and pollen. One such contaminant, the fungicide boscalid, is applied at bloom in orchards for fungal floral pathogen control. As an inhibitor of complex II in the mitochondrial electron transport chain of fungi, boscalid can potentially interfere with high energy-demanding activities of bees, including flight. We designed an indoor flight treadmill to evaluate impacts of ingesting boscalid and/or quercetin, a ubiquitous phytochemical in bee food that also affects mitochondrial respiration. Boscalid reduced the wingbeat frequencies of foragers during flight but did not alter the duration of flight. At the colony level, boscalid ingestion may thereby affect overall health by reducing forager efficiency. The consumption of quercetin, by contrast, led to higher adenosine triphosphate levels in flight muscles and a higher wingbeat frequency. Consuming the two compounds together increased wingbeat frequency, demonstrating a hitherto unrecognized mechanism by which dietary phytochemicals may act to ameliorate toxic effects of pesticides to promote honeybee health. In carrying out this work, we also introduce two methodological improvements for use in testing for pesticide effects on flight capacity—a ‘force-feeding’ to standardize flight fuel supply and a novel indoor flight treadmill.

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