Chronic sublethal pesticide exposure affects brood production, morphology and endosymbionts, but not immunity in the ant, Cardiocondyla obscurior

Sublethal concentrations of clothianidin affect honey bee colony growth and hive CO2 concentration

Scientific Reports ◽

10.1038/s41598-021-83958-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

William G. Meikle ◽

John J. Adamczyk ◽

Milagra Weiss ◽

Janie Ross ◽

Chris Werle ◽

...

Keyword(s):

Honey Bee ◽

Pesticide Exposure ◽

Co2 Concentration ◽

Colony Growth ◽

Control Group ◽

Brood Production ◽

Weight Losses ◽

Bee Colony ◽

The Impact ◽

Bee Colonies

AbstractThe effects of agricultural pesticide exposure upon honey bee colonies is of increasing interest to beekeepers and researchers, and the impact of neonicotinoid pesticides in particular has come under intense scrutiny. To explore potential colony-level effects of a neonicotinoid pesticide at field-relevant concentrations, honey bee colonies were fed 5- and 20-ppb concentrations of clothianidin in sugar syrup while control colonies were fed unadulterated syrup. Two experiments were conducted in successive years at the same site in southern Arizona, and one in the high rainfall environment of Mississippi. Across all three experiments, adult bee masses were about 21% lower among colonies fed 20-ppb clothianidin than the untreated control group, but no effects of treatment on brood production were observed. Average daily hive weight losses per day in the 5-ppb clothianidin colonies were about 39% lower post-treatment than in the 20-ppb clothianidin colonies, indicating lower consumption and/or better foraging, but the dry weights of newly-emerged adult bees were on average 6–7% lower in the 5-ppb group compared to the other groups, suggesting a nutritional problem in the 5-ppb group. Internal hive CO2 concentration was higher on average in colonies fed 20-ppb clothianidin, which could have resulted from greater CO2 production and/or reduced ventilating activity. Hive temperature average and daily variability were not affected by clothianidin exposure but did differ significantly among trials. Clothianidin was found to be, like imidacloprid, highly stable in honey in the hive environment over several months.

Download Full-text

Effects of neonicotinoid insecticide exposure and monofloral diet on nest-founding bumblebee queens

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2018.0761 ◽

2018 ◽

Vol 285 (1880) ◽

pp. 20180761 ◽

Cited By ~ 18

Author(s):

Mar Leza ◽

Kristal M. Watrous ◽

Jade Bratu ◽

S. Hollis Woodard

Keyword(s):

Pesticide Exposure ◽

Activity Levels ◽

Pollination Services ◽

Brood Production ◽

Initiation Phase ◽

Colony Cycle ◽

Neonicotinoid Insecticide ◽

Monofloral Pollen ◽

Bumblebee Pollination ◽

Nest Initiation

Bumblebees are among the world's most important groups of pollinating insects in natural and agricultural ecosystems. Each spring, queen bumblebees emerge from overwintering and initiate new nests, which ultimately give rise to workers and new reproductives later in the season. Nest initiation and survival are thus key drivers of both bumblebee pollination services and population dynamics. We performed the first laboratory experiment with the model bumblebee species Bombus impatiens that explores how early nesting success is impacted by the effects of temporary or more sustained exposure to sublethal levels of a neonicotinoid-type insecticide (imidacloprid at 5 ppb in nectar) and by reliance on a monofloral pollen diet, two factors that have been previously implicated in bumblebee decline. We found that queens exhibited increased mortality and dramatically reduced activity levels when exposed to imidacloprid, as well as delayed nest initiation and lower brood numbers in the nest, but partially recovered from these effects when they only received early, temporary exposure. The effects of pollen diet on individual queen- and colony-level responses were overshadowed by effects of the insecticide, although a monofloral pollen diet alone was sufficient to negatively impact brood production. These findings speak to the sensitivity of queen bumblebees during the nest initiation phase of the colony cycle, with implications for how queens and their young nests are uniquely impacted by exposure to threats such as pesticide exposure and foraging habitat unsuitability.

Download Full-text

Initial Exposure of Wax Foundation to Agrochemicals Causes Negligible Effects on the Growth and Winter Survival of Incipient Honey Bee (Apis mellifera) Colonies

Insects ◽

10.3390/insects10010019 ◽

2019 ◽

Vol 10 (1) ◽

pp. 19 ◽

Cited By ~ 4

Author(s):

Alexandria N. Payne ◽

Elizabeth M. Walsh ◽

Juliana Rangel

Keyword(s):

Honey Bee ◽

Pesticide Exposure ◽

Synergistic Effects ◽

Colony Growth ◽

Winter Survival ◽

Food Storage ◽

Brood Production ◽

Initial Exposure ◽

Growth And Survival ◽

Overwintering Survival

Widespread use of agrochemicals in the U.S. has led to nearly universal contamination of beeswax in honey bee hives. The most commonly found agrochemicals in wax include beekeeper-applied miticides containing tau-fluvalinate, coumaphos, or amitraz, and field-applied pesticides containing chlorothalonil or chlorpyrifos. Wax contaminated with these pesticides negatively affects the reproductive quality of queens and drones. However, the synergistic effects of these pesticides on the growth and survival of incipient colonies remain understudied. We established new colonies using frames with wax foundation that was pesticide free or contaminated with field-relevant concentrations of amitraz alone, a combination of tau-fluvalinate and coumaphos, or a combination of chlorothalonil and chlorpyrifos. Colony growth was assessed by estimating comb and brood production, food storage, and adult bee population during a colony’s first season. We also measured colony overwintering survival. We found no significant differences in colony growth or survivorship between colonies established on pesticide-free vs. pesticide-laden wax foundation. However, colonies that had Varroa destructor levels above 3% in the fall were more likely to die over winter than those with levels below this threshold, indicating that high Varroa infestation in the fall played a more important role than initial pesticide exposure of wax foundation in the winter survival of newly established colonies.

Download Full-text