Slowing Pollinator Declines (Research)

Better indicators of toxicity for pollinators can help to focus conservation efforts

Credit: Bigstock

Problem

How can we better understand and mitigate the role of insecticides in the decline of pollinators and other nontarget insects in recent years?

Widespread declines in pollinator populations and other beneﬁcial insects threaten production of pollinator-dependent food crops, wild plants, and natural ecosystems.
The use of insecticides in agriculture and other settings is believed to play a part in this decline.

Findings

Integrating federal data on insecticide use, toxicity, and crop acreage, a team led by Penn State researchers generated county-level annual estimates of honey bee “toxic load" from 1997 to 2012.

The total toxic load of insecticides applied to U.S. agricultural landscapes has become signiﬁcantly more toxic—over 120-fold in some Midwestern states—to honey bees when ingested.
This increase is largely due to rising use of neonicotinoid seed treatments in corn and soybean.

Impact

The study is the ﬁrst to identify geographic patterns of insecticide toxicity to bees and reveal speciﬁc areas of the country where mitigation and conservation efforts could be focused. The indicator used—bee-toxic load—can serve as an alternative to the commonly used measure of “pounds of insecticide applied" in cases where impacts to bees and other nontarget insects are a concern.

Related Research Areas: Integrated Health Solutions, Environmental Resilience

Research Credit

Team

Christina Grozinger, Maggie Douglas, Douglas Sponsler, Eric Lonsdorf

Participating Departments

Entomology

Partners

Dickinson College, University of Minnesota

Competitive Funding

USDA NIFA (Agriculture and Food Research Initiative), Foundation for Food and Agricultural Research, National Science Foundation/National Socio-Environmental Synthesis Center, USDA Economic Research Service

Federal and State Appropriations

USDA NIFA Hatch Multistate Project PEN04716, Accession #1020527

Emerging Discoveries

Insecticides becoming more toxic to honey bees

January 21, 2020

During the past 20 years, insecticides applied to U.S. agricultural landscapes have become significantly more toxic — over 120-fold in some midwestern states — to honey bees when ingested, according to a team of researchers, who identified rising neonicotinoid seed treatments in corn and soy as the primary driver of this change. The study is the first to characterize the geographic patterns of insecticide toxicity to bees and reveal specific areas of the country where mitigation and conservation efforts could be focused.