[font face=Serif]April 2, 2013
[font size=5]Total Buzz Kill: Metals in Flowers May Play Role in Bumblebee Decline[/font]
[font size=4]Pitt study finds that bees are at risk of ingesting toxic amounts of aluminum and nickel found in flowers growing in polluted soil[/font]
[font size=3]PITTSBURGHBeekeepers and researchers nationally are reporting growing evidence that
a powerful new class of pesticides may be killing off bumblebees. Now, research at the University of Pittsburgh points toward another potential cause: metal pollution from aluminum and nickel.
Published in the journal
Environmental Pollution, the Pitt study finds that bumblebees are at risk of ingesting toxic amounts of metals like aluminum and nickel found in flowers growing in soil that has been contaminated by exhaust from vehicles, industrial machinery, and farming equipment. The Pitt study finds that bumblebees have the ability to tasteand later ignorecertain metals such as nickel, but can do so only after they visit a contaminated flower. Therefore, the insects are exposed to toxins before they even sense the presence of metals.
Although many metals are required by living organisms in small amounts, they can be toxic to both plants and animals when found in moderate to high concentrations, said Tia-Lynn Ashman, principal investigator of the study and professor and associate chair in Pitts Department of Biological Sciences in the Kenneth P. Dietrich School of Arts and Sciences. Beyond leading to mortality, these metals can interfere with insect taste perception, agility, and working memoryall necessary attributes for busy bumblebee workers.
To determine whether nickel and aluminum in the flowers nectar influenced bumblebee behavior, Ashman and Meindl used two groups of uncontaminated flowers, one group of flowers contaminated by nickel, and another contaminated by aluminum. When a bumblebee visited a flower in an array, the entire visitation was recorded as well as the time spent (in seconds) foraging on each individual flower. This included monitoring whether the bee moved from a contaminated to a noncontaminated flower, whether the bee moved to the same group it had just sampled, or whether the bee left the flower group without visiting other individual blooms. Following each observed visit, all flowers in the array were replaced with new flowers, to ensure accurate results.
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