2nd Place: Fungicide exposure reduces learning performance and homing ability in honey bees (Apis mellifera)

Monday, November 14, 2022

9:00 AM – 9:12 AM PT

Location: Vancouver Convention Centre, Meeting Room 213

Presenting Author(s)

Nicole S. DesJardins

PhD Candidate
Arizona State University
Tempe, Arizona

Co-Author(s)

Adrian L. Fisher II, II

Postdoctoral Research Associate
Arizona State University
Tempe, Arizona
Jon F. Harrison

Professor
Arizona State University
Tempe, Arizona
BS

Brian H. Smith

Geospatial Academies Co-Facilitator
Arizona State University
Tempe, Arizona

Pollinator populations globally have declined at concerning rates in recent years, which is problematic given that at least 35 percent of all food production depends on them. Managed honey bee colony losses in particular have alarmed beekeepers and scientists, especially in the United States. Widespread agrochemical use has been implicated as one of the major causes of these colony losses. While the lethal effects of agrochemicals are the primary basis for judging their safety to arthropods, sublethal behavioral effects can occur at much lower doses and substantially weaken colonies. In this experiment, we fed honey bee (Apis mellifera) colonies pollen containing a field-realistic concentration of the fungicide Pristine^® (active ingredients: 25.2% boscalid, 12.8% pyraclostrobin). Bees reared during the period of Pristine^® consumption showed impaired olfactory associative learning performance in a proboscis extension reflex (PER) assay; only about 20 percent of Pristine^®-exposed bees successfully learned the association between odor and reward. Bees reared during the exposure period also had reduced homing ability, tested by an experiment in which we released foragers in the field at set distances away from their hives. Bees exposed to Pristine^® took longer than controls to return home. Together, these behavioral impairments may reduce foraging capabilities and cause some foragers to become lost and unable to return to their hive. We conclude that normal agricultural use of this approved fungicide can have significant negative effects on honey bee behavioral performance, with potential fitness effects on the colony. This research was partially supported by USDA 2017-68004-26322.