By: Michelle L. Hladik, Mark Vandever, Kelly L. Smalling.

Extract

The awareness of insects as pollinators and indicators of environmental
quality has grown in recent years, partially
in response to declines in honey bee (Apis mellifera) populations. While
most pesticide research has focused on
honey bees, there has been less work on native bee populations. To determine
the exposure of native bees to pesticides,
bees were collected from an existing research area in northeastern Colorado
in both grasslands (2013-
2014) and wheat fields (2014). Traps were deployed bi-monthly during the
summer at each land cover type
and all bees, regardless of species,were composited aswhole samples and
analyzed for 136 current-use pesticides
and degradates. This reconnaissance approach provides a sampling of all
species and represents overall pesticide
exposure (internal and external). Nineteen pesticides and degradateswere
detected in 54 composite samples collected.
Compounds detected in N2% of the samples included: insecticides thiamethoxam
(46%), bifenthrin (28%),
clothianidin (24%), chlorpyrifos (17%), imidacloprid (13%), fipronil
desulfinyl (7%; degradate); fungicides
azoxystrobin (17%), pyraclostrobin (11%), fluxapyroxad (9%), and
propiconazole (9%); herbicides atrazine (19%)
andmetolachlor (9%). Concentrations ranged from1 to 310 ng/g for individual
pesticides. Pesticideswere detected
in samples collected from both grasslands and wheat fields; the location of
the sample and the surrounding land
cover at the 1000 m radius influenced the pesticides detected but because of
a small number of temporally comparable
samples, correlations between pesticide concentration and land cover were
not significant. The results
show native bees collected in an agricultural landscape are exposed
tomultiple pesticides, these results can direct
future research on routes/timing of pesticide exposure and the design of
future conservation efforts for pollinators.


Free available via:
http://www.apinews.com/en/component/k2/item/29617.

Kind regards,

Ghislain De Roeck,
Belgium.

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