Great New Paper Out: Effects of Pesticides on Bees

Continuing with the pollination theme, here’s a new paper out on the topic:

Crop Pollination Exposes Honey Bees to Pesticides Which Alters Their Susceptibility to the Gut Pathogen Nosema ceranae


Recent declines in honey bee populations and increasing demand for insect-pollinated crops raise concerns about pollinator shortages. Pesticide exposure and pathogens may interact to have strong negative effects on managed honey bee colonies. Such findings are of great concern given the large numbers and high levels of pesticides found in honey bee colonies. Thus it is crucial to determine how field-relevant combinations and loads of pesticides affect bee health. We collected pollen from bee hives in seven major crops to determine 1) what types of pesticides bees are exposed to when rented for pollination of various crops and 2) how field-relevant pesticide blends affect bees’ susceptibility to the gut parasite Nosema ceranae. Our samples represent pollen collected by foragers for use by the colony, and do not necessarily indicate foragers’ roles as pollinators. In blueberry, cranberry, cucumber, pumpkin and watermelon bees collected pollen almost exclusively from weeds and wildflowers during our sampling. Thus more attention must be paid to how honey bees are exposed to pesticides outside of the field in which they are placed. We detected 35 different pesticides in the sampled pollen, and found high fungicide loads. The insecticides esfenvalerate and phosmet were at a concentration higher than their median lethal dose in at least one pollen sample. While fungicides are typically seen as fairly safe for honey bees, we found an increased probability of Nosema infection in bees that consumed pollen with a higher fungicide load. Our results highlight a need for research on sub-lethal effects of fungicides and other chemicals that bees placed in an agricultural setting are exposed to.

Pettis, J.S., E.L. Lichtenberg, M. Andree, et al. July 2013.  PLOS ONE, 8:7 Article Number: e70182   DOI: 10.1371/journal.pone.0070182

Cranberry Pollination Research at the University of Wisconsin

In the spring and summer of 2012, Hannah Gaines, a PhD student in the Entomology Department at the University of Wisconsin, did experiments in the field and in the greenhouse to better understand what non-bee factors may be influencing cranberry pollination.

Hannah's cages

Monitoring one of my pollination treatment cages in the field.

Hannah's greenhouse experiment

Hand pollinating cranberry plants in the greenhouse.

Hannah's greenhouse experiment

Hand pollinating cranberry plants in the greenhouse.

To learn more about her work on native pollinators, see this article.

Are you interested in learning about pollinators and the services that they provide?

This week’s Entomology seminar, on Friday April 20, will be given by Dr. Eric Lonsdorf, of the Chicago Botanic Garden, and is entitled “Modeling Pollination Services Across Agricultural Services.” For more information, click here.

Also, next week, the Entomology Department will be hosting another pollinator seminar by Dr. Sai Suryanarayanan of UW-Madison’s Department of Community and Environmental Sociology, entitled “Finding Sustainable Solutions to Honey Bee and Pollinator Health.”

–Liz Bosak