> What infective agent could cause foragers to not return to hives?

I have been writing about this for months. Fifty years ago, Bailey showed
that sacbrood virus in the brains of bees can cause premature foraging.
Jasna Kralj wrote in the ABJ about the "suicide hypothesis" which posits
sick bees may deliberately fly off and not return, or at the very least --
engage in risky behavior. 

Pesticides can cause bees to become disoriented but the researchers have
repeatedly placed this factor at the bottom of the list. It is much more
plausible (to me, anyway) that an accumulation of toxins, chiefly viral, in
the brains of the bees is triggering an early shift to foraging behavior,
and possibly combined with neurological damage, their foraging period (which
is short in any case) is drastically reduced.

pb 

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