> >But, of course, public health professionals would laugh at
> such a study because regardless of any adverse health effects,
> pigeons thrive in downtown Los Angeles and Mexico City.


Paul makes an excellent point.  Another example is that there was a recent
paper suggesting that the amygdalin in almond nectar is toxic to bees.
However, the practical experience of beekeepers who eagerly place their bees
on that bloom for buildup flies in the face of that finding.

An instructive review of the significance of sublethal effects testing can
be found in Thompson and Maus (2007) Perspective:  The relevance of
sublethal effects in honey bee testing for pesticide risk assessment.  Pest
Manag Sci 63:1058–1061

"It is also an open question whether the results of
tests on sublethal effects other than under field (or
semi-field) conditions, especially when only effects on
individuals are measured, can really be extrapolated
to a realistic field situation with bee colonies. For
instance, a behavioural effect seen in individuals will
not necessarily have a potential to cause harm at the
colony level."

"If the protection goal for honey
bees is considered to be to prevent significant colony
losses and thus economic and ecological damage, then
the same protection goal should be applied to both
mortality-based and sublethal effects. Therefore, the
link between the sublethal effect under evaluation and
colony damage must be demonstrated if such effects
are to be given the same weight as mortality in risk
assessment."

"In regulatory ecotoxicological testing there is a hierar-
chical tiered study system that includes the fundamen-
tal principle that lower-tier studies are overridden by
the results of higher-tier (more realistic) studies. This
means for bee testing that, where appropriate higher-
tier studies (tunnel, field) are available, the conduct of
specific laboratory-based sublethal studies is unneces-
sary, and higher-tier data should override the results
of possible sublethal studies. Sublethal effects, if they
occur and are ecologically relevant, should also be
apparent under appropriately designed field or tunnel
conditions, otherwise they can be considered artefacts
of laboratory conditions and thus not relevant for the
final risk assessment. Whether a semi-field or a field
design is more appropriate to address a certain type of
effect will depend on the specific nature of the effect
under consideration. So far there is no indication that
sublethal effects that might be relevant could not be
covered by semi-field or field study designs"

The bottom line is, despite the results of lab tests, does a pesticide
actually cause measurable harm to a colony in actual field conditions?

Randy Oliver

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