As per combining of corn, bees collecting dust. The bees don't need to be
anywhere near the combines.
Based on years of using bees as environmental sentinels, chemical samplers
- we know that the body of each flying bee is electrostatically charged.
Under a microscope, one can see dust particles, spores, bacteria adsorbed
(and yes, I meant to say adsorb rather than absorb) to the cuticle. We've
even modeled uptake based on particle size and charge.
For any chemical that adheres to dust, the route of exposure for bees is
not simply pollen, nectar. The dust itself (soils, re-entrained soil dust,
plumes from factories) may be as important in terms of exposure levels or
even more so than exposures from pollen or nectar.
That's certainly the case near industrial sources that emit plumes
containing heavy metals. In exclusion trials, we found that the majority of the
exposure of bees to materials like arsenic, cadmium, zinc, copper was from
the dusts that sorbed on their bodies. The next highest route of exposure,
but still trivial compared to the direct dust exposure, was pollen. Nectar
was a distant 3rd.
Also, even inert dusts can be hazardous to bees. The spiracle aren't well
designed to shield the bee from dust, smothering. And the materials may
act as dessicants and abrasives. Mt St Helen's ash was mostly inert, but it
caused brood breaks and some adult bee losses.
Jerry
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