Impacts of pesticide-contaminated pollen food stores on the larvae of solitary bee Osmia cornifrons

On-Demand

Presenting Author(s)

Ngoc T. Phan (she/her/hers)

Postdoctoral Fellow
University of Arkansas
Fayetteville, Arkansas

Co-Author(s)

NJ

Neelendra K. Joshi

Entomologist
University of Arkansas
Fayetteville, Arkansas
Margarita López-Uribe (she/her/hers)

Associate Professor
Pennsylvania State University
University Park, Pennsylvania
FZ

Fang Zhu

Professor
Pennsylvania State University
State College, Pennsylvania
KP

Kari A. Peter

Pennsylvania State University
Biglerville, Pennsylvania
ER

Edwin G. Rajotte

Pennsylvania State University
University Park, Pennsylvania
DB

David J. Biddinger

Research Professor
Pennsylvania State University
Biglerville, Pennsylvania

Solitary bees are often exposed to various pesticides applied for pest control on farmland while providing pollination services to food crops. Increasing evidence suggests that sublethal toxicity of agricultural pesticides affects solitary bees differently than the social bees used to determine regulatory thresholds like honey bees and bumblebees. Studies on solitary bees are challenging because of the difficulties in obtaining large numbers of eggs or young larvae for bioassays. Here we show the toxic and sublethal developmental effects of four widely used plant systemic pesticides on the Japanese orchard bee (Osmia cornifrons). Pollen food stores of this solitary bee were treated with different concentrations of three insecticides (acetamiprid, flonicamid, and sulfoxaflor) and a fungicide (dodine). Eggs were transplanted to the treated pollen and larvae were allowed to feed on the pollen stores after egg hatch. The effects of chronic ingestion of contaminated pollen were measured until adult eclosion. This year-long study revealed that chronic exposure to all tested pesticides delayed larval development and lowered larval and adult body weights. Additionally, exposure to the systemic fungicide resulted in abnormal larval defecation and increased mortality at the pupal stage, indicating potential risk to bees from fungicide exposure. These findings demonstrate potential threats to solitary bees from systemic insecticides and fungicides and will help making policy decisions for mitigating these effects.