Intensively cultivated landscape and <i>Varroa</i> mite infestation are associated with reduced honey bee nutritional state

Biblio

Publication Type:

Journal Article

Source:

PLoS ONE, Volume 11, p.e0153531 (2016)

Keywords:

honey bee, Varroa mite

Abstract:

<p>As key pollinators, honey bees are crucial to many natural and agricultural ecosystems. An<br />
important factor in the health of honey bees is the availability of diverse floral resources. However,<br />
inmany parts of the world, high-intensity agriculture could result in a reduction in honey<br />
bee forage. Previous studies have investigated how the landscape surrounding honey bee<br />
hives affects some aspects of honey bee health, but to our knowledge there have been no<br />
investigations of the effects of intensively cultivated landscapes on indicators of individual<br />
bee health such as nutritional physiology and pathogen loads. Furthermore, agricultural landscapes<br />
in different regions vary greatly in forage and land management, indicating a need for<br />
additional information on the relationship between honey bee health and landscape cultivation.<br />
Here, we add to this growing body of information by investigating differences in nutritional<br />
physiology between honey bees kept in areas of comparatively low and high cultivation in an<br />
area generally high agricultural intensity in the Midwestern United States.We focused on<br />
bees collected directly before winter, because overwintering stress poses one of the most<br />
serious problems for honey bees in temperate climates.We found that honey bees kept in<br />
areas of lower cultivation exhibited higher lipid levels than those kept in areas of high cultivation,<br />
but this effect was observed only in colonies that were free of Varroa mites. Furthermore,<br />
we found that the presence of mites was associated with lower lipid levels and higher titers of<br />
deformed wing virus (DWV), as well as a non-significant trend towards higher overwinter<br />
losses. Overall, these results show that mite infestation interacts with landscape, obscuring<br />
the effects of landscape alone and suggesting that the benefits of improved foraging landscape<br />
could be lost without adequate control of mite infestations.</p>