title: The fungicide Pristine® inhibits mitochondrial function in vitro but not flight metabolic rates in honey bees.
abstract: Honey bees and other pollinators are exposed to fungicides that act by inhibiting fungal mitochondria. Here we test whether a common fungicide (Pristine®) inhibits the function of mitochondria of honeybees, and whether consumption of ecologically-realistic concentrations can cause negative effects on the mitochondria of flight muscles, or the capability for flight, as judged by CO2 emission rates and thorax temperatures during flight. Direct exposure of mitochondria to Pristine® levels above 5 ppm strongly inhibited mitochondrial oxidation rates in vitro. However, bees that consumed pollen containing Pristine® at ecologically-realistic concentrations (≈ 1 ppm) had normal flight CO2 emission rates and thorax temperatures. Mitochondria isolated from the flight muscles of the Pristine®-consuming bees had higher state 3 oxygen consumption rates than control bees, suggesting that possibly Pristine®-consumption caused compensatory changes in mitochondria. It is likely that the lack of a strong functional effect of Pristine®-consumption on flight performance and the in vitro function of flight muscle mitochondria results from maintenance of Pristine® levels in the flight muscles at much lower levels than occur in the food, probably due to metabolism and detoxification. As Pristine® has been shown to negatively affect feeding rates and protein digestion of honey bees, it is plausible that Pristine® consumption negatively affects gut wall function (where mitochondria may be exposed to higher concentrations of Pristine®).
authors.affiliation: School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA. Electronic address: Jacob.Campbell.1@asu.edu.
authors.forename: Jacob B
authors.initials: JB
authors.lastname: Campbell
authors.affiliation: School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA. Electronic address: rnath@asu.edu.
authors.forename: Rachna
authors.initials: R
authors.lastname: Nath
authors.affiliation: School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA. Electronic address: Juergen.Gadau@asu.edu.
authors.forename: Juergen
authors.initials: J
authors.lastname: Gadau
authors.affiliation: School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA. Electronic address: tpfox1@asu.edu.
authors.forename: Trevor
authors.initials: T
authors.lastname: Fox
authors.affiliation: USDA, ARS, Honey Bee Research, 2000 East Allen Road, Tucson, AZ 85719, USA. Electronic address: Gloria.Hoffman@ars.usda.gov.
authors.forename: Gloria
authors.initials: G
authors.lastname: DeGrandi-Hoffman
authors.affiliation: School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA. Electronic address: j.harrison@asu.edu.
authors.forename: Jon F
authors.initials: JF
authors.lastname: Harrison
mesh_terms: D000367:Age Factors; D000818:Animals; D001516:Bees / Q000187:drug effects*; D001713:Biphenyl Compounds / Q000633:toxicity*; D001831:Body Temperature / Q000187:drug effects; D002219:Carbamates / Q000633:toxicity*; D019069:Cell Respiration / Q000187:drug effects; D005260:Female; D005426:Flight, Animal / Q000187:drug effects*; D008928:Mitochondria / Q000187:drug effects*; D009536:Niacinamide / Q000031:analogs & derivatives* / Q000633:toxicity; D011720:Pyrazoles / Q000633:toxicity*
chemical_list: D001713:Biphenyl Compounds; D002219:Carbamates; C000608450:Pristine (fungicide); D011720:Pyrazoles; D009536:Niacinamide
keywords: Flight; Fungicide; Honey bee; Mitochondria; Pristine®