[Pollinator] A Second Pollinator Release to Consider Sharing on Listserver (Urban Environments Boost Pathogen Press on Honey Bees)

[Puckett, Catherine]

Hi there -- here is a second release we'd like to ask you to consider
sharing. The research was supported by the USGS National Climate and
Wildlife Science Center/the Interior Department's Southeast Climate Science
Center.


https://news.ncsu.edu/2015/11/tarpy-frank-2015/


Urban Environments Boost Pathogen Pressure on Honey Bees

Photo credit: Elsa Youngsteadt.
For Immediate Release

November 4, 2015

Elsa Youngsteadt <ekyoungs at ncsu.edu>

Steve Frank <steven_frank at ncsu.edu>  |  919.515.8880

David Tarpy <david_tarpy at ncsu.edu>  |  919.515.1660

Matt Shipman <matt_shipman at ncsu.edu>  |  919.515.6386

Researchers from North Carolina State University have found that urban
environments increase pathogen abundance in honey bees (*Apis mellifera*)
and reduce honey bee survival. The finding raises significant questions as
urban areas continue to grow at the expense of rural environments, and
urban beekeeping becomes more popular.

“We wanted to determine if the increased temperatures and impervious
surface areas associated with urban environments have an effect on the
number of pathogens bees are exposed to, and to the bees’ immune
responses,” says Steve Frank, an associate professor of entomology at NC
State and co-author of a paper on the work.

“We also wanted to look at both managed honey bee colonies and ‘wild’ ones,
to see if that made a difference – and it did,” says David Tarpy, a
professor of entomology at NC State and corresponding author on the paper.

Working with volunteers, the researchers identified 15 feral colonies,
living in trees or buildings without human management, and 24 colonies
managed by beekeepers in urban, suburban, and rural areas within an hour’s
drive of Raleigh, N.C. The researchers collected worker bees from all of
the colonies, and analyzed them to assess the bees’ immune responses and
their overall “pathogen pressure.” Pathogen pressure accounts for both the
types of pathogen species present and the abundance of those pathogens.

The research team found that colonies closer to urban areas and those
managed by bee keepers had higher pathogen pressure.

“Overall, we found that the probability of worker [bee] survival in
laboratory experiments declined three-fold in bees collected from urban
environments, as compared to those collected in rural environments,” Frank
says.

However, the researchers also found that immune response was not affected
by urbanization.

“Since immune response is the same across environments, we think the higher
pathogen pressure in urban areas is due to increased rates of
transmission,” Tarpy says. “This might be because bee colonies have fewer
feeding sites to choose from in urban areas, so they are interacting with
more bees from other colonies. It may also be caused by higher temperatures
in urban areas affecting pathogen viability or transmission somehow.”

“Feral bees expressed some immune genes at nearly twice the levels of
managed bees following an immune challenge,” Frank says. The finding
suggests that further study of feral bee colonies may give researchers
insights that could improve honey bee management.

“Honey bees are important pollinators and play a significant role in our
ecosystems and our economy,” Tarpy says. “This work is really only a
starting point. Now that we know what’s happening, the next step is to
begin work on understanding why it is happening and if the same negative
effects of urbanization are hurting solitary, native bee species that are
presumably more sensitive to their local environment.”

The paper, “Urbanization Increases Pathogen Pressure on Feral and Managed
Honey Bees <http://dx.plos.org/10.1371/journal.pone.0142031>,” was
published Nov. 4 in the journal *PLOS ONE*. The co-lead authors of the
paper are Elsa Youngsteadt, an entomology research associate at NC State,
and Holden Appler, a former graduate student at NC State. The paper was
co-authored by Margarita López-Uribe, a postdoctoral researcher at NC State.

The work was supported by Agriculture and Food Research Initiative grant
number 2013-02476 from the U.S. Department of Agriculture’s National
Institute of Food and Agriculture; the North Carolina Department of
Agriculture and Consumer Services; a Dean’s Enrichment Grant from the NC
State College of Agriculture and Life Sciences; a gift from the North
Carolina State Beekeepers Association; and by the Department of the
Interior’s Southeast Climate Science Center, under cooperative agreement
numbers G11AC20471 and G13AC00405. The center is based at NC State and
provides scientific information to help land managers respond effectively
to climate change.

-shipman-

*Note to Editors:* The study abstract follows.

*“Urbanization Increases Pathogen Pressure on Feral and Managed Honey Bees”*

*Authors*: Elsa Youngsteadt, R. Holden Appler, Margarita M. López-Uribe,
David R. Tarpy and Steven D. Frank, North Carolina State University

*Published*: Nov. 4, *PLOS ONE*

*DOI*: 10.1371/journal.pone.0142031

*Abstract:* Given the role of infectious disease in global pollinator
decline, there is a need to understand factors that shape pathogen
susceptibility and transmission in bees. Here we ask how urbanization
affects the immune response and pathogen load of feral and managed colonies
of honey bees (*Apis mellifera* Linnaeus), the predominant economically
important pollinator worldwide. Using quantitative real-time PCR, we
measured expression of 4 immune genes and relative abundance of 10 honey
bee pathogens. We also measured worker survival in a laboratory bioassay.
We found that pathogen pressure on honey bees increased with urbanization
and management, and the probability of worker survival declined 3-fold
along our urbanization gradient. The effect of management on pathogens
appears to be mediated by immunity, with feral bees expressing immune genes
at nearly twice the levels of managed bees following an immune challenge.
The effect of urbanization, however, was not linked with immunity; instead,
urbanization may favor viability and transmission of some disease agents.
Feral colonies, with lower disease burdens and stronger immune responses,
may illuminate ways to improve honey bee management. The previously
unexamined effects of urbanization on honey-bee disease are concerning,
suggesting that urban areas may favor problematic diseases of pollinators.
-------------------------------------------------------
 🐝Catherine Puckett
Deputy Public Affairs Officer
USGS Office of Communications
352-377-2469 (O)  352-278-0165 (cell)
cpuckett at usgs.gov
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